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Research Article
Phylogenetic and morphological classification of Ophiocordyceps species on termites from Thailand
expand article infoKanoksri Tasanathai, Wasana Noisripoom, Thanyarat Chaitika, Artit Khonsanit, Sasitorn Hasin§, Jennifer Luangsa-ard
‡ Bioscience and Biotechnology for Agriculture, Pathum Thani, Thailand
§ Valaya Alongkorn Rajabhat University under the Royal Patronage, Pathum Thani, Thailand
Open Access

Abstract

Seven new species occurring on termites are added to OphiocordycepsO. asiatica, O. brunneirubra, O. khokpasiensis, O. mosingtoensis, O. pseudocommunis, O. pseudorhizoidea and O. termiticola, based on morphological and molecular phylogenetic evidence. O. brunneirubra possesses orange to reddish-brown immersed perithecia on cylindrical to clavate stromata. O. khokpasiensis, O. mosingtoensis and O. termiticola have pseudo-immersed perithecia while O. asiatica, O. pseudocommunis and O. pseudorhizoidea all possess superficial perithecia, reminiscent of O. communis and O. rhizoidea. Phylogenetic analyses based on a combined dataset comprising the internal transcribed spacer regions (ITS) and the largest subunit (LSU) of the ribosomal DNA, partial regions of the elongation factor 1-α (TEF) and the largest and second largest subunits for the RNA polymerase genes (RPB1, RPB2) strongly support the placement of these seven new species in Ophiocordyceps.

Keywords

Entomopathogenic fungi, Hypocreales, Isoptera, Ophiocordycipitaceae, Taxonomy

Introduction

The entomopathogenic genus Ophiocordyceps was established by Petch in 1931. His description was based on four specimens including O. blattae Petch, the type species, occurring on a cockroach collected from Sri Lanka, O. unilateralis (Tul. & C. Tul.) Petch on ants, O. peltata (Wakef.) Petch on Coleoptera larva (Cryptorhynchus sp.) and O. rhizoidea (Höhn.) Petch on Coleoptera larva. The distinction of the genus from Cordyceps Fr. was made due the presence of clavate asci that gradually narrowed to a thickened apex, as opposed to the cylindrical asci in many Cordyceps species. The ascospores in Ophiocordyceps sensu Petch are elongated fusoid, multi-septate that remain whole after discharge. Sung et al. (2007) emended the definition of Ophiocordyceps to contain the anamorphic genera Hirsutella Pat., Hymenostilbe Petch, Paraisaria Samson & Brady and Syngliocladium Petch, with the stromata or subiculum of the teleomorphs mostly darkly pigmented [e.g. O. acicularis (Ravenel) Petch, O. heteropoda (Kobayasi) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora, O. entomorrhiza (Dicks.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora, O. unilateralis species complex] and sometimes brightly coloured [e.g. O. irangiensis (Moureau) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora, O. nutans (Pat.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora, O. sphecocephala (Klotzsch ex Berk.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora]. The ascospores are usually cylindrical, multi-septate that could either dissociate into part-spores (O. sphecocephala, O. nutans) or remain whole ascospores (O. unilateralis). To date, Ophiocordyceps is the most speciose genus in Ophiocordycipitaceae with 235 names of accepted species (Spatafora et al. 2015; Khonsanit et al. 2018; Luangsa-ard et al. 2018). Most Asian species of Ophiocordyceps have fibrous, hard and pliant to wiry, dark coloured stromata with superficial to immersed perithecia (Kobayasi 1941; Kobmoo et al. 2012, 2015; Luangsa-ard et al. 2018).

Only a few species of entomopathogenic fungi have been reported from termites. Currently accepted species include Ophiocordyceps bispora (Stifler) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora on Macrotermes from Tanzania, O. koningsbergeri (Penz. & Sacc.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora, known only from the type locality (Java, Indonesia) (Kobayasi 1941), C. termitophila Kobayasi & Shimizu known from Japan and Taiwan (Kobayasi and Shimizu 1978) and O. octospora (M. Blackw. & Gilb.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora on Tenuirostritermes from Mexico (Blackwell and Gilbertson 1981). Penzig and Saccardo (1904) found O. koningsbergeri to be similar to O. myrmecophila (Ces., in Rabenshorst 1858) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora in that it had a terminal, globose head with immersed perithecia.

Termites (Isoptera) are one of the eusocial and soil insects that have successfully evolved since the Cretaceous Period and are classified into 7 families, 14 subfamilies, 280 genera and 2,500 species (Pearce 1999). They occur throughout tropic and subtropic regions and can also be found in many temperate areas and semi-arid environments of the world (Eggleton et al. 2000). Termites are abundant in Thailand and are found in natural forests as well as urban areas, mostly considered as serious pests of wooden constructions. Current records of termite species from Thailand have been 199 species, 39 genera, 10 subfamilies and 4 families (Sornnuwat et al. 2004). Relationships between termites and fungi are classified into two categories. Firstly, termites cultivate fungi (Termitomyces spp.) in their fungus gardens within the subterranean nest or mound of fungus-growing termites (subfamily Macrotermitinae). Secondly, a parasitic interaction, in which fungi infect and consume termites as food for its nutrient value (Abe et al. 2000). Some species of fungi are known as pathogens of termites and they can be used as potential agents of biological control for each of the host’s (i.e. termites) specificities (Rath 2000).

In surveys of entomopathogenic fungi in national parks and community forests collections of termite pathogens, most with superficial perithecia and rarely with immersed perithecia were found. The phenotypic characters of the collections in having wiry and pliant, darkly pigmented stromata identifies them primarily to be members of the Ophiocordycipitaceae, mostly as Ophiocordyceps communis. The aims of this study are (1) to clarify the relationships of these collections to known members of the Ophiocordycipitaceae, (2) to uncover hidden species in O. communis species complex and (3) to describe new taxa to accommodate species diversity in Ophiocordyceps.

Material and methods

Collection and isolation

Species occurring on termites (Isoptera) were found in the ground. The specimens were excavated carefully so as not to lose the host, which could be buried as deep as 15 cm under the ground and were placed in small plastics boxes before returning to the laboratory for isolation. The materials were examined under a stereomicroscope (OLYMPUS SZ61, Olympus Corporation, Japan). The fertile heads of the specimens containing mature perithecia were carefully placed over the Potato Dextrose Agar plate (PDA; fresh diced potato 200 g, dextrose 20 g, agar 15 g, in 1 litre distilled water). These were placed in a plastic box with moist tissue paper overnight to create a humid chamber. The following morning plates were examined with a stereomicroscope to check the discharged ascospores. Discharged ascospores were examined daily for germination and also for fungal contaminants.

Morphological study

The newly collected specimens were noted and photographed in the field using a digital Nikon D5100 camera and were taken to the laboratory and photographed using an Olympus SZX12 before they were placed in a moist chamber to facilitate ascospore discharge. The colour of the freshly collected specimens and cultures were characterised with the colour standard of the Online Auction Colour Chart. One to two perithecia were removed from the stroma and mounted on a glass slide using lactophenol cotton blue to measure their sizes and shapes, as well as the sizes and shapes of the asci and ascospores. Cultures on PDA, Potato Sucrose Agar plate (PSA: potato 200 g/l, sucrose 20 g/l, calcium carbonate 5g/l, agar 20g/l) and quarter strength Sabouraud Dextrose Yeast Agar (SDYA/4; Difco) were observed using light microscopy (Olympus SZ60, CX 30) daily to check for germination and contamination for 2–3 wks. Colony growth rates and characteristics (colour, texture, pigmentation) under dark/light condition (L:D = 14:10) were recorded and photos were taken using the Nikon D5100 camera.

For micro-morphological description, microscope slide cultures were prepared from a block of media (PDA, PSA and SDYA/4, ca. 5 × 5 mm2) inoculated with the fungus and overlaid by a glass coverslip. The cultures were incubated at 25 °C. Observations, measurements of the conidiogenous cells and conidia of the asexual morphs and photographs were taken with an Olympus DP11 microscope.

Host identification

Dead termite hosts were identified, based on morphological characteristics, such as mandibulate mouthparts, antennae, shape of head and thoraxes. The identification of dead insects was conducted after pure cultures were acquired. Termites were identified by using the extant families of Isoptera after Sornnuwat et al. (2004) and Krishna et al. (2013).

DNA extraction, PCR amplification and sequencing

Cultivation of fungi for molecular work. – Pure cultures were grown on PDA. After approximately 2 wks, the plates were checked for contaminants and small agar blocks were inoculated into sterile Erlenmeyer flasks containing 50 ml Sabouraud Dextrose Broth (Difco) and incubated for 1–2 wks at 25 °C without shaking. Mycelium was then harvested by filtration and washed several times with sterile distilled water. Filtered mycelium was lyophilised. The material was extracted from mycelium by a modified CTAB method as previously described (Luangsa-ard et al. 2004, 2005).

PCR amplification. – Five nuclear loci including the nuc rDNA region encompassing the internal transcribed spacers 1 and 2, along with the 5.8S rDNA (ITS), nuc 28S rDNA (LSU), the translation elongation factor 1-α gene (TEF) and the genes for RNA polymerase II largest (RPB1) and second largest (RPB2) subunits were sequenced. PCR primers used to amplify the gene regions for this study were: ITS5, ITS4 for ITS, LROR and LR7 for LSU (White et al. 1990), 983F and 2218R for TEF, CRPB1 and RPB1Cr for RPB1, RPB2-5F2 and RPB2-7Cr for RPB2 (Castlebury et al. 2004). The PCR reaction mixture consisted of 1× PCR buffer, 200 μM of each of the four dNTPs, 2.5 mM MgCl2, 0.4 M Betaine, 1 U Taq DNA Polymerase, recombinant (Thermo Scientific, US) and 0.2 μM of each primer in a total volume of 50 μl. PCR cycle conditions were as previously described in Sung et al. (2007). PCR amplicons were visualised by ethidium bromide staining after gel electrophoresis of 4 µl of the product in 0.8% agarose gel. Quantification of the PCR products was performed using a standard DNA marker of known size and weight. PCR products were purified using Qiagen columns (QIAquick PCR Purification Kit). Purified PCR products were sequenced with the PCR amplification primers.

Sequencing alignment and phylogenetic analyses

The DNA sequences, generated in this study, were examined for ambiguous bases using BioEdit 7.2.5 (Hall 2004) and then submitted to GenBank (Table 1). The dataset of taxa in Cordycipitaceae was assembled from previously published studies (Sung et al. 2007; Kepler et al. 2017) and were downloaded from GenBank for the construction of the phylogenetic tree (Table 1). Alignments were performed using MUSCLE 3.6 software with default settings (Edgar 2004). Sequences of Cordyceps kyusyuensis and Cordyceps militaris in the Cordycipitaceae were used as the outgroup.

Maximum Likelihood (ML) analyses was performed with RAxML-HPC2 on XSEDE v8.2.10 (Stamatakis 2014) with the use of GAMMA Model parameters. The reliability of ML internal branches was assessed using a non-parametric bootstrap method with 1000 replicates. Bayesian (BI) phylogenetic inference was performed with MrBayes on XSEDE v3.2.6 (Ronquist and Huelsenbeck 2003) using the GTR+I+G model as selected by MrModeltest v2.2 (Nylander 2004). The chain length of the Bayesian analyses was 5,000,000 generations, sampled every 1000 generations and a burn-in of 10% of the total run. Maximum parsimony analysis was conducted on the combined dataset using PAUP 4.0b10 (Swofford 2002).

Table 1.

List of species and GenBank accession numbers of sequences used in this study.

Species Strain nr. Host/Substratum GenBank accession no.
ITS rDNA LSU TEF RPB1 RPB2
Cordyceps kyusyuensis EFCC 5886 Lepidoptera EF4688131 EF4687541 EF4688631 EF4689171
Cordyceps militaris OSC 93623 Lepidoptera JN0498251 AY1849661 DQ5223321 DQ5223771 AY5457321
Drechmeria gunnii OSC 76404 Lepidoptera (pupa) AF3395222 AY4896162 AY4896502 DQ5224262
Drechmeria sinensis CBS 567.95 Nematoda AJ2924172 AF3395452 DQ5223432 DQ5223892 DQ5224432
Hirsutella cf. haptospora ARSEF 2228 Diptera: Itonididae KM6521663 KM6521183 KM6520013 KM6520413
Hirsutella citriformis ARSEF 1446 Hemiptera; Cixiidae KM6521543 KM6521063 KM6519903 KM6520313
ARSEF 1035 Hemiptera; Cixiidae KM6521533 KM6521053 KM6519893 KM6520303
Hirsutella cryptosclerotium ARSEF 4517 Hemiptera; Pseudococcidae KM6521573 KM6521093 KM6519923 KM6520323
Hirsutella fusiformis ARSEF 5474 Coleoptera: Curculionidae KM6521103 KM6519933 KM6520333
Hirsutella gigantea ARSEF 30 Hymenoptera: Pamphiliidae JX5669803 KM6520343
Hirsutella haptospora ARSEF 2226 Acari: Uropodina KM6521593 KM6519953 KM6520363
Hirsutella illustris ARSEF 5539 Hemiptera: Aphididae KM6521603 KM6521123 KM6519963 KM6520373
Hirsutella lecaniicola ARSEF 8888 Hemiptera: Coccidae KM6521623 KM6521143 KM6519983 KM6520383
Hirsutella liboensis ARSEF 9603 Lepidoptera: Cossidae KM6521633 KM6521153
Hirsutella necatrix ARSEF 5549 Acari KM6521643 KM6521163 KM6519993 KM6520393
Hirsutella nodulosa ARSEF 5473 Lepidoptera; Pyralidae KM6521653 KM6521173 KM6520003 KM6520403
Hirsutella radiata ARSEF 1369 Diptera KM6521193 KM6520023 KM6520423
Hirsutella repens nom. inval. ARSEF 2348 Hemiptera: Delphacidae KM6521673 KM6521203 KM6520033
Hirsutella rhossiliensis ARSEF 2931 Tylenchida: Heteroderidae KM6521683 KM6521213 KM6520043 KM6520433
Hirsutella satumaensis ARSEF 996 Lepidoptera: Pyralidae KM6521723 KM6521253 KM6520083 KM6520473
Hirsutella sp. ARSEF 8378 Hemiptera: Cixiidae KM6521273 KM6520103 KM6520493
Hirsutella strigosa ARSEF 2197 Hemiptera: Cicadellidae KM6521753 KM6521293 KM6520123 KM6520503
ARSEF 2044 Hemiptera: Delphacidae KM6521743 KM6521283 KM6520113
Hirsutella subulata ARSEF 2227 Lepidoptera: Microlepidoptea KM6521763 KM6521303 KM6520133 KM6520513
Hirsutella thompsonii ARSEF 257 Acari; Eriophyidae KM6521823 KM6521363 KM6520193 KM6520543
ARSEF 414 Acari; Eriophyidae KM6521843 KM6521393 KM6520213 KM6520563
ARSEF 3323 Acari: Tenuipalpidae KM6521883 KM6521433 KM6520243 KM6520593
ARSEF 3482 KM6521893 KM6521443 KM6520253 KM6520603
ARSEF 253 Acari: Eriophyidae KM6521793 KM6521333 KM6520163
ARSEF 256 Acari: Eriophyidae KM6521813 KM6521353 KM6520183 KM6520533
ARSEF 258 Acari: Eriophyidae KM6521373 KM6520203 KM6520553
ARSEF 2800 Acari KM6521873 KM6521423 KM6520233 KM6520583
Hirsutella thompsonii “var. synnematosa ARSEF 1947 Acari: Tarsonemidae KM6521913 KM6521463 KM6520263
ARSEF 5412 Acari: Tetranychidae KM6521933 KM6521483
Hirsutella thompsonii var. vinacea ARSEF 254 Acari: Eriophyidae KM6521943 KM6521493 KM6520283 KM6520623
Hirsutella versicolor ARSEF 1037 Hemiptera: Membracidae KM6521503 KM6520293 KM6520633
Ophiocordyceps acicularis OSC 110988 Coleoptera (larva) EF4688042 EF4687452 EF4688532
OSC 110987 Coleoptera (larva) EF4688052 EF4687442 EF4688522
Ophiocordyceps agriotidis ARSEF 5692 Coleoptera (larva) JN0498192 DQ5187542 DQ5223222 DQ5223682 DQ5224182
Ophiocordyceps aphodii ARSEF 5498 Coleoptera DQ5187552 DQ5223232 DQ5224192
Ophiocordyceps appendiculata NBRC 106960 Coleoptera (larva) JN9433262 JN9414132 JN9924622
Ophiocordyceps asiatica BCC 30516 Termitidae (adult termite) MH754722 MH753675 MK284263 MK214105 MK214091
BCC 86435 Termitidae (adult termite) MH754723 MH753676 MK214106 MK214092
Ophiocordyceps communis BCC 1842 Termitidae (adult termite) MH754726 MH753680 MK284266 MK214110 MK214096
BCC 1874 Termitidae (adult termite) MH754725 MH753679 MK284267 MK214109 MK214095
BCC 2754 Termitidae (adult termite) MH754727 MH753681 MK284268 MK214111 MK214097
Ophiocordyceps brunneipunctata OSC 128576 Coleoptera (Elateridae larva) DQ5187562 DQ5223242 DQ5223692 DQ5224202
Ophiocordyceps brunneirubra BCC 14384 Termitidae (adult termite) MH754736 MH753690 GU797121 MK751465 MK751468
BCC 14478 Termitidae (adult termite) MH754734 MH753688 GU797122 MK751466 MK214102
BCC 14477 Termitidae (adult termite) MH754735 MH753689 GU797123 MK751467 MK214103
Ophiocordyceps dipterigena OSC 151911 Diptera (adult fly) KJ8788864 KJ878966 4 KJ8790004
Ophiocordyceps elongata OSC 110989 Lepidoptera (larva) EF4688082 EF4687482 EF4688562
Ophiocordyceps gracilioides HUA 186095 Coleoptera (Elateridae larva) KM4119942 KP2129142
HUA 186092 Coleoptera (Elateridae larva) KJ1309922 KP2129152
Ophiocordyceps gracilis EFCC 8572 Lepidoptera (larva) JN0498512 EF4688112 EF4687512 EF4688592 EF4689122
EFCC 3101 Lepidoptera (larva) EF4688102 EF4687502 EF4688582 EF4689132
Ophiocordyceps granospora BCC 82255 Hymenoptera (Polyrhachis sp.) MH0281434 MH0281564 MH0281834 MH028164 MH028174
Ophiocordyceps heteropoda EFCC 10125 Hemiptera (cicada nymph) JN0498522 EF4688122 EF4687522 EF4688602 EF4689142
Ophiocordyceps irangiensis BCC 82793 Hymenoptera (Polyrhachis illaudata) MH0281414 MH0281854 MH0281634 MH028174
BCC 82795 Hymenoptera (Polyrhachis sp.) MH0281424 MH0281864 MH0281644 MH028174
Ophiocordyceps khaoyaiensis BCC 82796 Hymenoptera (Polyrhachis armata) MH0281504 MH0281534 MH0281874 MH0281654 MH028174
BCC 82797 Hymenoptera (Polyrhachis armata) MH0281514 MH0281544 MH0281884 MH0281664 MH028174
Ophiocordyceps khokpasiensis BCC 48071 Termitidae (adult termite) MH754728 MH753682 MK284269 MK214112
BCC 48072 Termitidae (adult termite) MH754729 MH753683 MK284270 MK214113
BCC 1764 Termitidae (adult termite) MH754730 MH753684 MK284271 MK214114 MK214098
Ophiocordyceps konnoana EFCC 7315 Coleoptera (larva) EF4687532 EF4688612 EF4689162
Ophiocordyceps longissima NBRC 108989 Hemiptera (cicada nymph) AB9684071 AB9684211 AB9685851
EFCC 6814 Hemiptera (cicada nymph) EF4688172 EF4687572 EF4688652
Ophiocordyceps mosingtoensis BCC 30904 Termitidae (adult termite) MH754732 MH753686 MK284273 MK214115 MK214100
BCC 36921 Termitidae (adult termite) MH754731 MH753685 MK284272 MK214116 MK214099
Ophiocordyceps myrmecophila CEM 1710 Hymenoptera (Adult ant) KJ8788944 KJ8789744 KJ8790084
Ophiocordyceps myrmicarum ARSEF 11864 Hymenoptera: Formicidae JX5669733 KJ6801513
Ophiocordyceps nigrella EFCC 9247 Lepidoptera (larva) JN0498532 EF4688182 EF4687582 EF4688662 EF4689202
Ophiocordyceps pseudocommunis BCC 16757 Termitidae (adult termite) MH754733 MH753687 MK284274 MK214117 MK214101
Ophiocordyceps pseudocommunis NHJ 12581 Termitidae (adult termite) EF4688313 EF4687753 EF4689303
NHJ 12582 Termitidae (adult termite) EF4688303 EF4687713 EF4689263
Ophiocordyceps pseudorhizoidea BCC 48879 Termitidae (adult termite) MH754720 MH753673 MK284261 MK214104 MK214089
BCC 86431 Termitidae (adult termite) MH754721 MH753674 MK284262 MK751469 MK214090
NHJ 12522 Termitidae (adult termite) JN0498572 EF4688252 EF4687642 EF4688732 EF4689232
NHJ 12529 Termitidae (adult termite) EF4688242 EF4687652 EF4688722 EF4689222
Ophiocordyceps pulvinata TNS-F-30044 Hymenoptera GU9042095 GU9042105
Ophiocordyceps ravenelii OSC 110995 Coleoptera (larva) DQ5187642 DQ5223342 DQ5223792
Ophiocordyceps robertsii KEW 27083 Lepidoptera (Hepialidae larva) EF4688262 EF4687662
Ophiocordyceps satoi J7 Hymenoptera (Polyrhachis lamellidens) KX7135995 KX7136835 KX7137115
J19 Hymenoptera (Polyrhachis lamellidens) KX7136015 KX7136845 KX7137105
Ophiocordyceps sinensis ARSEF 6282 Lepidoptera; Hepialidae KM6521733 KM6521263 KM6520093 KM6520483
EFCC 7287 Lepidoptera; Hepialidae (larva) JN0498542 EF4688272 EF4687672 EF4688742 EF4689252
Ophiocordyceps sobolifera KEW 78842 Hemiptera (cicada nymph) JN0498552 EF4688282 EF4688752 DQ5224322
Ophiocordyceps spataforae NHJ 12525 Hemiptera EF4690786 EF4690636 EF4690926 EF4691116
OSC 128575 Hemiptera EF4690796 EF4690646 EF4690936 EF4691106
Ophiocordyceps sphecoceplala NBRC 101416 Hymenoptera (adult wasp) JN9414434 JN9924324
Ophiocordyceps stylophora OSC 111000 Coleoptera; Elateridae (larva) JN0498282 DQ5187662 DQ5223372 DQ5223822
Ophiocordyceps termiticola BCC 1920 Termitidae (adult termite) MH754724 MH753678 MK284265 MK214108 MK214094
BCC 1770 Termitidae (adult termite) GU723780 MH753677 MK284264 MK214107 MK214093
Ophiocordyceps unilateralis OSC 128574 Hymenoptera DQ5187682 DQ5223392 DQ5223852 DQ5224362
Ophiocordyceps xuefengensis GZUHHN 13 Lepidoptera; Phassus nodus (larva) KC6318042 KC6317902 KC6317952
Ophiocordyceps yakusimensis HMAS 199604 Hemiptera; (cicada nymph) KJ8789022 KJ8790182 KJ8789532
Purpureocillium lilacinum CBS 284.36 Soil AY6241892 EF4687922 EF4688982 EF4689412
CBS 431.87 Nematoda AY6241882 EF4688442 EF4687912 EF4688972 EF4689402

Results

Phylogenetic analysis

We obtained 96 new sequences from 20 specimens (Table 1). The combined dataset of five genes consisted of 4013 bp (ITS 527 bp, LSU 824 bp, TEF 901 bp, RPB1 874 bp, RPB2 854 bp) and 99 taxa were analysed.

The ML and BI analyses displayed similar topologies resolving seven new species in Ophiocordyceps (Fig. 1). The final ML optimisation likelihood = -51972.210615 and tree length = 5.567057. The parameters included base frequencies—A = 0.227576, C = 0.299408, G = 0.284488, T = 0.188528 and the rate matrix for the substitution model: [AC] = 1.240734, [A-G] = 2.882814, [A-T] = 0.983408, [C-G] = 1.338444, [C-T] = 5.445401, [G-T] = 1. 000000. In the BI analyses, the model selected was GTR+I+G, -lnL = 52578.1641. The parameters used included base frequencies—freqA = 0.1918, freqC = 0.3427, freqG = 0.2769, freqT = 0.1886 and the rate matrix for the substitution model: [AC] = 1.2356, [A-G] = 3.1814, [A-T] = 1.1029, [C-G] = 1.1220, [C-T] = 4.7720, [G-T] = 1.0000. The MP analyses resulted in 32 equally most parsimonious trees with 4013 characters, 1912 of which are constant, 355 are variable and parsimony-uninformative, while 1746 are parsimony-informative and tree length has 10669 steps (CI, 0.348; RI, 0.689; RC, 0.240; HI, 0.652).

Figure 1. 

Phylogenetic tree based on combined data set of ITS, LSU, TEF, RPB1 and RPB2 sequences showing the relationship of seven new species on termites from Thailand with other species of Ophiocordyceps. Numbers above lines at significant nodes represent Maximum Likelihood bootstrap values, Bayesian posterior probabilities and MP bootstrap values. Bold lines mean support for the tree analyses were 100%.

Taxonomy

Ophiocordyceps asiatica Tasanathai, Noisripoom & Luangsa-ard, sp. nov.

MycoBank No: MycoBank MB 831297
Figure 2

Typification

THAILAND. Nakhon Ratchasima Province, Khao Yai National Park; 14°711'N, 101°421'E; on termite; 21 May 2008; K. Tasanathai, S. Mongkolsamrit, B. Thongnuch, P. Srikitikulchai, R. Ridkaew, A. Khonsanit (holotype BBH 38718 dried culture; ex-type living culture, BCC 30516). GenBank: ITS = MH754722, LSU = MH753675, TEF = MK284263, RPB1 = MK214105, RPB2 = MK214091

Figure 2. 

Ophiocordyceps asiatica (BBH38718, BCC30516) A stroma of fungus emerging from termite B phialide on specimen C part of stroma showing perithecia D perithecium E asci F ascospores G colony on PDA at 20 d obverse and reverse H, I phialides with conidia on PDA J, K conidium L colony on PSA at 20 d obverse and reverse M, N phialides with conidia on PSA O conidium P colony on SDYA/4 at 20 d obverse and reverse Q, R phialides with conidia S conidia T–X scanning electron micrographs of phialides with conidia on PDA. Scale bars: 10 mm (A, G, L, P); 5 μm (B); 1 mm (C); 8 μm (D); 15 μm (E); 10 μm (F, I); 3 μm (H, J, K, M, N, S, T, V); 2 μm (O, Q, R, U, W, X).

Etymology

asiatica’ referring to Asia.

Description

Stroma solitary, simple, filiform, up to 15 cm long, 1 mm wide, orange-brown (oac48-50), ca. 10 cm emerging above leaf litter, 5 cm buried in the soil. Asexual state (Hirsutella) produced at the terminal part of the stroma, ca. 2 cm long, light brown to grey. Perithecia superficial covering middle part of stroma, globose to subglobose, (240–)261.5–302(–320) × (180–)205–240.5(–260) µm. Asci 8-spored, filiform, (92.5–)104–143.5(–175) × 5–6.5 µm with cap, 2 × 2 µm. Ascospores whole, filiform, (80–)100–122.5(–132.5) × 1–2 µm, with septate. Asexual state Hirsutella, phialides arising singly or laterally from the hyphae along the terminal part of the stroma, (9–)9.5–13(–15) × (3–)3.5–4.8(–5) µm, conidia hyaline, fusiform, 4–5×2–3 µm.

Culture characteristics

Colonies on PDA, attaining a diam. of 27 mm after 20 d at 25 °C, mycelium sparse to abundant, grey in the middle to pale brown. Conidiogenous cells developing directly on the aerial mycelium, swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin warty neck (1 µm), monophialidic or rarely polyphialidic 15–18.5(–20) × 2–3 µm µm. Conidia aseptate, hyaline, smooth, arising from phialides at the apex of each neck, fusiform, (7–)7.6–9 × 2–3 µm, with a mucous sheath.

Colonies on PSA, attaining a diam. of 25 mm after 20 d at 25 °C, Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic, (15–)17–21(–23) × 3–4 µm. Conidia aseptate, hyaline, smooth, arising from phialides at the apex of each neck, fusiform, (6–)6.5–8.5(–10) × 2–3 µm, with a mucous sheath.

Colonies on SDYA/4, slow-growing, attaining a diam. of 30 mm after 20 d at 25 °C. Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic or polyphialidic, (10–)12–15(–17) × (2–)2.5–3 µm. Conidia aseptate, hyaline, smooth, arising from phialides at the apex of each neck, fusiform, (7–)8.5–11.5(–13) × 2–3 µm, with a mucous sheath.

Distribution

Thailand, only known from Khao Yai National Park.

Ecology

Parasitic on a pair of termites from a reproductive caste (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae) and these specimens were buried in the soil. The fungus emerged from the segment between the prothorax and mesothorax of one of the termite pairs.

Additional specimens examined

THAILAND. Saraburi Province, Khao Yai National Park; 14°586'N, 100°998'E; on termite; 4 June 2017; S. Mongkolsamrit, U. Pinruan, P. Srikitikulchai, R. Promharn, S. Sommai (BBH45363, BBC86435).

Notes

Four species, O. asiatica, O. communis, O. pseudocommunis and O. pseudorhizoidea look morphologically similar in having superficial perithecia and long wiry, pliant stroma emerging from the ground. In O. asiatica and O. communis, the stroma is dark brown, while in O. pseudocommunis and O. pseudorhizoidea it is cream to light brown. The perithecia in O. communis, O. pseudocommunis and O. pseudorhizoidea are larger than O. asiatica, but its ascospores are larger than in O. pseudorhizoidea.

Ophiocordyceps brunneirubra Tasanathai, Noisripoom, Luangsa-ard & Hywel Jones, sp. nov.

MycoBank No: MycoBank MB 831289
Figure 3

Typification

THAILAND. Uthai Thani Province, Huai Kha Khaeng Wildlife Sanctuary; 15°605'N, 99°330'E; on termite; 28 August 2003; N.L. Hywel-Jones (holotype BBH 9008 dried culture; ex-type living culture: BCC14478). GenBank: ITS = MH754734, LSU = MH753688, TEF = GU797122, RPB1 = MK751466, RPB2 = MK214102

Figure 3. 

Ophiocordyceps brunneirubra (BBH 9008, BCC14478) A, B fungus on termite C part of stroma showing perithecia D immersed perithecia E asci F ascospore G, H colony on PDA at 20 d (G) colony obverse (H) colony reverse I, J, K phialides with conidia on PDA L, M conidia on PDA N, P, O sclerotia formed in culture Q, R, S scanning electron micrographs of phialides with conidia T, U colony on PSA at 20 d (T) colony obverse (U) colony reverse V, W, X phialides with conidia on PSA Y conidia on PSA. Scale bars: 25 mm (A); 15 mm (B, G, H, T, U); 1 mm (C); 130 μm (D); 10 μm (I, Q, W); 15 μm (J); 3 μm (K, R); 5 μm (L); 4 μm (M, S, Y); 6 μm (V); 7 μm (X).

Etymology

brunneirubra’ referring to the reddish-brown appearance of the fertile head.

Description

Stroma solitary, simple or branched, narrowly clavate, slender and wiry, up to 9.5 cm long, 0.5 mm wide. Fertile head cylindric, orange brown (oac642) to red brown (oac635), up to 8 mm long, 1 mm wide. Perithecia immersed, ovoid, ordinal in arrangement, (300–)334.5–400(–403) × (130–)138.5–178(–200) µm. Asci 8-spored, cylindrical, (155–)176–214.5(–225) × 4.5–7(–8) µm. Ascospores whole, filiform, 156.5–197.5 × 2–3 µm, with septa.

Culture characteristics

Colonies on PDA, attaining a diam. of 25 mm within 20 d at 25 °C, orange (oac651) to orange brown (oac639). Conidiogenous cells monophialidic, arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck, (32–)35.5–43.5(–50) µm long, (2–)2.5–3µm wide at the base, 1–1.5 µm wide at tip with warty surface. Conidia hyaline, one-celled, with a distinct gold cap covering the tip of the conidia, fusiform, (12–)13.5–15.5(–17) × 2–3 (–4) µm. Sclerotia formed in culture after 1 month, dark brown (oac635).

Colonies on PSA, attaining a diam. of 25 mm within 20 d at 25 °C, orange brown (oac716) to brown (oac721), reverse orange brown (oac721). Conidiogenous cells monophialidic, arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck, (30–)32.5–39.5(–41) µm long, (2–)2.5–3.5(–4) µm wide at the base, 1–1.5 µm wide at tip with warty surface. Conidia hyaline, one-celled, arising from phialides, with a distinct gold cap covering the tip of the conidia, fusiform, (13–)14–16(–17) × 2–3 µm.

Colonies on SDYA/4, attaining a diam. of 25 mm within 20 d at 25 °C, dark brown (oac733), reverse orange brown (oac728). Conidiogenous cells monophialidic, arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck, 25–40 µm long, 2–4 µm wide at the base, 1 µm wide at tip with warty surface. Conidia hyaline, one-celled, arising from phialides, with a distinct gold cap covering the tip of the conidia, fusiform, 12–15 × 2–3 µm.

Distribution

Thailand, only known from Huai Kha Kaeng Wildlife Sanctuary.

Ecology

Parasitic on a subterranean termite (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae), collected from the soil. These termites belong to the reproductive caste (king or queen alates). The fungus emerged from between head and thoraxes of termite alates.

Additional specimens examined

THAILAND. Uthai Thani Province, Huai Kha Khaeng Wildlife Sanctuary; at 15°605'N, 99°330'E; on termites; 28 Aug 2003; N.L. Hywel-Jones (BBH9009, BCC14477), (BBH9005, BCC14384).

Notes

This species differs from other species on termites collected in Thailand in being singly infected by fungus instead of termite pairs and having immersed perithecia and red brown fertile terminal stroma. The species is not commonly found since it could easily be mistaken as a plant material sprouting from the ground. It is reminiscent of O. brunneipunctata but only on a different host. The shape of the conidia, like a banana with a hat or a cap, has never been seen in any kind of fungal spore morphology before.

Ophiocordyceps khokpasiensis Tasanathai, Noisripoom & Luangsa-ard, sp. nov.

MycoBank No: MycoBank MB 831290
Figure 4

Typification

THAILAND. Kalasin Province, Phu Si Than Wildlife Sanctuary, Khok Pa Si Community Forest; 16°562'N, 104°103'E; on termite; 14 June 2011; K. Tasanathai, P. Srikitikulchai, A. Khonsanit, K. Sansatchanon, W. Noisripoom (holotype BBH32173 dried culture; ex-type living culture: BCC48071). GenBank: ITS = MH754728, LSU = MH753682, TEF = MK284269, RPB1 = MK214112

Figure 4. 

Ophiocordyceps khokpasiensis (BBH32173, BCC48071) A fungus on termite B part of stroma showing perithecia C pseudo-immersed perithecia D asci E ascospore F phialides with conidia from synnema G conidia from synnema H colony on PDA at 20 d colony obverse and reverse I, J phialides with conidia on PDA K, L conidium M, N, O scanning electron micrographs of phialides with conidia on PDA P colony on PSA at 20 d obverse and reverse Q, R, S phialides with conidia on PDA T, U conidium V colony on SDYA/4 at 20 d obverse and reverse W, X, Y phialides with conidia Z conidium. Scale bars: 2.5 cm (A); 1 mm (B); 100 µm (C); 5 µm (D, G, I, J, K, L); 20 µm (E); 6 µm (F); 7 mm (H, P, V); 3 µm (M, N, O, Q, R, S, T, U); 4 µm (W, X, Y); 2 µm (Z).

Etymology

khokpasiensis’ referring to Khok Pa Si community forest, site of collection of type species.

Description

Stroma solitary, simple, cylindrical, 16 cm long, 1 mm wide, brown (oac48-50), ca. 5.5 cm emerging above the leaf litter, ca. 10.5 cm buried in the soil. Asexual state (Hirsutella) produced ca. 1.5 cm at the terminal part of the stroma, light brown to grey. Perithecia pseudo-immersed, subglobose to broadly ellipsoidal, covering middle part of stroma, (200–)214–248.5(–250) × (120–)140–186(–200) µm. Asci 8-spored, filiform, (62.5–)86–115(–125) × 4–5 µm. Ascospores whole, filiform, (46–)51–74(–90) × 2–3 µm. Asexual state Hirsutella, phialides arising singly or laterally from the hyphae along the terminal part of the stroma, (8–)9–11(–12) × 3–4 µm. Conidia, hyaline, oval, 5–6.5(–7) × 2–3 µm.

Culture characteristics

Colonies on PDA, attaining a diam. of 25.5 mm within 20 d at 25 °C, cream (oac900) to grey (oac893). Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic or polyphialidic, (15–)16.5–23(–28) × 3–4.5(–5) µm. Conidia arising from phialides at the apex of each neck, globose to oval, one-celled (4–)4.5–5.5(–6) × 2.5–4 µm, embedded in a mucous sheath.

Colonies on PSA, attaining a diam. of 24 mm within 20 d at 25 °C, white to grey (oac843). Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic or polyphialidic, (14–)15.5–22.5(–28) × 3–4.5(–5) µm. Conidia arising from phialides at the apex of each neck, globose to oval, one-celled 4–5(–6) × (2–)2.5–3.5(–5) µm, embedded in a mucous sheath.

Colonies on SDYA/4, attaining a diam. of 25 mm within 20 d at 25 °C, grey to brown (oac473). Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic or polyphialidic, (9–)11.5–15.5(–19) × (2–)3–3.5(–4) µm. Conidia arising from phialides at the apex of each neck, globose to oval, one celled 3.5–4.5(–5) × 2.5–3 (–3.5) µm, embedded in a mucous sheath.

Distribution

North-eastern Thailand.

Ecology

Parasitic on a pair of termites from a reproductive caste (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae) and these specimens were buried in the soil. The fungus emerged from the segment between the prothorax and mesothorax of one of the termite pairs.

Additional specimens examined

THAILAND. Saraburi Province, Namtok Samlan National Park (Phra Buddha Chai); 14°526'N, 100°9'E; on termite; 15 June 1996; Hywel-Jones, NL (BBH5116, BCC1764). Kalasin Province: Phu Si Than Wildlife Sanctuary, Khok Pa Si Community Forest; 16°562'N, 104°103'E; on termite; 14 June 2011; K. Tasanathai, P. Srikitikulchai, A. Khonsanit, K. Sansatchanon, W. Noisripoom (BBH32173, BCC48072).

Notes

Other Ophiocordyceps species reported on termites with pseudo-immersed perithecia are O. mosingtoensis and O. termiticola. O. khokpasiensis and O. termiticola shares similarity in the colour of the perithecia but in O. termiticola, the perithecia are denser while it is loosely arranged in O. khokpasiensis. O. mosingtoensis produces a more robust stroma compared to O. khokpasiensis and O. termiticola. The gross morphology of O. khokpasiensis is similar to O. asiatica, O. communis, O. pseudocommunis and O. pseudorhizoidea. However, all these other species produce superficial perithecia.

Ophiocordyceps mosingtoensis Tasanathai, Noisripoom & Luangsa-ard, sp. nov.

MycoBank No: MycoBank MB 831291
Figure 5

Typification

THAILAND. Nakhon Ratchasima Province, Khao Yai National Park; 14°711'N, 101°421'E; on termite; 17 June 2009; K. Tasanathai, P. Srikitikulchai, S. Mongkolsamrit, T. Chohmee, R. Ridkaew, N.L. Hywel-Jones (holotype BBH26809 dried culture; ex-type living culture, BCC36921). GenBank: ITS = MH754731, LSU = MH753685, TEF = MK284272, RPB1 = MK214116, RPB2 = MK214099

Figure 5. 

Ophiocordyceps mosingtoensis (BBH26809, BCC36921) A stroma of fungus emerging from termite B part of stroma showing perithecia C pseudo-immersed perithecia D, E ascus F ascospore G, L, Q, V scanning electron micrographs of phialides with conidia on PDA H colony on PDA at 20 d obverse and reverse I, J phialides with conidia K conidium M colony on PSA at 20 d obverse and reverse N, O phialides with conidia P conidium R colony on SDYA/4 at 20 d obverse and reverse S, T phialides with conidia U conidium. Scale bars: 10 mm (A); 1 mm (B); 150 µm (C); 25 µm (D); 4 µm (E); 30 µm (F); 10 µm (G); 8 mm (H, M, R); 3 µm (I, J, N, O, S, T); 2 µm (K, L, P, Q, U); 1 µm (V).

Etymology

mosingtoensis’ referring to name after the type locality.

Description

Stroma solitary, simple, cylindrical, up to 11 cm long, 1 mm wide, brown (oac 48-50), ca. 8.5 cm emerging above the leaf litter, ca. 2.5 cm buried in the soil. Asexual state (Hirsutella) produced ca. 1 cm at the terminal part of the stroma, light brown to grey. Perithecia pseudo-immersed, broadly ovoid covering middle part of stroma, (400–)414–469 (–500) × (200–)208–263(–300) µm. Asci 8-spored, filiform, (187.5–) 217–265(–287.5) × 4.5–6.5(–7.5) µm with cap, 2 µm. Ascospores whole, filiform, (230–)240–291(–315) × 1.5–3 µm, with septa.

Culture characteristics

Colonies on PDA, attaining a diam. of 16 mm within 20 d at 25 °C, cream (oac872) to grey (oac909). Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic, (10–)12.5–16 (–17) × (2–) 2.5–3 µm. Conidia arising from phialides at the apex of each neck, oval, 3–4.5(–5) × 2–2.5(–3) µm.

Colonies on PSA, attaining a diam. of 17 mm within 20 d at 25 °C, white to grey (oac872). Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic, (10–)11.5–15(–17) × (2–)2.5–3.5(–4) µm. Conidia arising from phialides at the apex of each neck, oval, (3–)3.5–5(–5.5) × 2–3 µm.

Colonies on SDYA/4, attaining a diam. of 17 mm within 20 d at 25 °C, white to grey (oac802). Conidiogenous cells swollen towards the base, hyaline, smooth, tapering gradually towards the apex, which often forms a thin neck, monophialidic or polyphialidic, (9–)10.5–14.5(–17) × (2–)2.5–3 µm. Conidia arising from phialides at the apex of each neck, oval, (3–)3.5–4.5(–5) × 2–3 µm.

Distribution

Thailand, only known from Khao Yai National Park.

Ecology

Parasitic on a pair of termites from a reproductive caste (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae) and these specimens were buried in the soil. The fungus emerged from the segment between the prothorax and mesothorax of one of the termite pairs.

Additional specimens examined

THAILAND. Nakhon Ratchasima Province, Khao Yai National Park; 14°711'N, 101°421'E; on termite; 18 June 2008; J.J. Luangsa-ard, K. Tasanathai, S. Mongkolsamrit, B. Thongnuch, P. Srikitikulchai, R. Ridkaew (BBH 23860, BCC 30904).

Note

O. mosingtoensis has a sturdier, robust stroma compared with O. termiticola and O. khokpasiensis which also produce pseudo-immersed perithecia.

Ophiocordyceps pseudocommunis Tasanathai, Noisripoom & Luangsa-ard, sp. nov.

MycoBank No: MycoBank MB 831351
Figure 6

Typification

THAILAND. Nakhon Nayok Province, Khao Yai National Park; 14°163'N, 101°268'E; on termite; 13 July 2004; S. Sivichai, K. Tasanathai, N. Boonyuen, P. Puyngain (holotype BBH10001 dried culture; ex-type living culture, BCC16757). GenBank: ITS = MH754733, LSU = MH753687, TEF = MK284274, RPB1 = MK214117, RPB2 = MK214101

Figure 6. 

Ophiocordyceps pseudocommunis (BBH10001, BCC16757) A stroma of fungus emerging from termite B part of stroma showing superficial perithecia C perithecium D ascospore E phialides with conidia from synnema F conidia from synnema G, L, M, N, O, P scanning electron micrographs of phialides with conidia on PDA H colony on PDA at 20 d obverse and reverse I, J phialides with conidia on PDA K conidium Q colony on PDA at 20 d obverse and reverse R phialides with conidia on PSA S conidium T colony on SDYA/4 at 20 d obverse and reverse U phialides with conidia V conidium. Scale bars: 10 mm (A); 0.5 mm (B); 150 µm(C); 6 µm (D); 7 µm (E); 2 µm (F); 4 µm (G); 8 mm (H, Q, T); 8 µm (I); 5 µm (J, K, U, V); 3 µm (R, S).

Etymology

pseudocommunis’ referring to close affinity to Ophiocordyceps communis.

Description

Stroma solitary, simple, cylindrical, 21.5 cm long, 0.5 mm wide, brown (oac48-50), ca. 12 cm emerging above the leaf litter, ca. 9 cm buried in the soil. Asexual state (Hymenostilbe-like) produced ca. 5 cm at the terminal part of the stroma, light brown to brown. Perithecia superficial, subglobose, covering middle part of the stroma, (520–)536.5–596.5(–600) × (360–)373.5–425 (–440) µm. Asci, 8-spored, filiform, 160–164.5(–165) × 14–17 µm. Ascospores whole, filiform, (107.5–)120.5–138 (–147.5) × (6–)6.5–7 (7.5) µm, with 7–8 septa. Asexual state Hymenostilbe-like, conidiogenous cells forming a compact hymenium-like layer and had two to four denticles at their apices, cylindrical to clavate, (17–)18.5–21(–22) × (2–)2.5–7.5(–8) µm. Conidia, hyaline, fusiform, (6–)6.5–7.5(–8) × 2–3 µm.

Culture characteristics

Colonies on PDA, attaining a diam. of 26.5 mm within 20 d at 25 °C, white (oac909) to grey (oac851). Conidiogenous cells arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck. Conidia hyaline, septate (2–3), arising from phialides at the apex of each neck, fusiform, (13–)14.5–20.5(–27) × (3–)3.5–5 µm.

Colonies on PSA, attaining a diam. of 15 mm within 20 d at 25 °C, white (oac909) to grey (oac851). Conidiogenous cells arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck. Conidia hyaline, septate (1–4), arising from phialides at the apex of each neck, fusiform, (7–)9–15.5(–20) × (2–)2.5–4 µm.

Colonies on SDYA/4, attaining a diam. of 19 mm within 20 d at 25 °C, cream (oac816) to brown (oac781). Conidiogenous cells arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck. Conidia hyaline, septate, arising from phialides at the apex of each neck, fusiform, (7–)9–18.5(–27) × (3–)3.5–6(–8) µm.

Distribution

Only reported from Khao Yai National Park.

Ecology

Parasitic on a pair of termites from a reproductive caste (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae) and these specimens were buried in the soil. The fungus emerged from the segment between the prothorax and mesothorax of one of the termite pairs.

Additional specimens examined

THAILAND. Nakhon Ratchasima Province, Khao Yai National Park; 14°711'N, 101°421'E; on termite; 22 July 2003; R. Nasit, N.L. Hywel-Jones, J.W. Spatafora (NHJ12581, NHJ12582).

Ophiocordyceps pseudorhizoidea Tasanathai, Noisripoom & Luangsa-ard, sp. nov.

MycoBank No: MycoBank MB 830982
Figure 7

Typification

THAILAND. Khonkaen Province, Phu Wiang National Park; 16°799'N, 102°279'E; on termite; 17 July 2017; K. Tasanathai, S. Mongkolsamrit, W. Noisripoom (holotype BBH45361 dried culture; ex-type living culture, BCC86431). GenBank: ITS = MH754721, LSU = MH753674, TEF = MK284262, RPB1 = MK751469, RPB2 = MK214090

Figure 7. 

Ophiocordyceps pseudorhizoidea (BBH45361, BCC86431) A stroma of fungus emerging from termite B part of stroma showing perithecia C perithecia D, E ascus F ascospore G, H phialides with conidia from synnema I colony on PDA at 20 d obverse and reverse J, K, L phialides with conidia on PDA M, N, O conidium P colony on PSA at 20 d obverse and reverse Q, R, S phialides with conidia on PSA T, U conidia with mucous sheath. Scale bars: 15 mm (A); 1 mm (B); 120 μm (C); 8 μm (D, E); 10 μm (F, G); 3 μm (H, R); 6 mm (I, P); 5 μm (J, K, L, Q); 2 μm (M, N, O, T, U); 4 μm (S).

Etymology

pseudorhizoidea’ referring to close affinity to what was called Ophiocordyceps rhizoidea on termites by NHJ.

Description

Stroma solitary, simple, filiform, up to 21 cm long, 1 mm wide, light-brown (oac675), ca. 15 cm emerging above leaf litter, 5.5 cm buried in the soil. Asexual state (Hirsutella) produced at the terminal part of the stroma, ca. 6 cm long, light brown to grey. Perithecia superficial, ovoid, covering the middle part of stroma, (280–) 287.5–315.5 (–390) × (160–) 177–209.5 (–220) µm. Asci 8-spored, cylindrical, 120–150 × 5–7 µm with cap, 3–4 × 4–5 µm. Ascospores whole, filiform, (65–) 69.5–78.5 (–82.5) × 2–2.8 (–3) µm, with septate. Asexual state Hirsutella. Phialides (10–)15.5–23.5(–26) × 3–4(–5) µm, conidia hyaline, fusiform, (5–)5.5–6.5(–7) × 3–4 µm.

Culture characteristics

Colonies on PDA, attaining a diam. of 10 mm within 20 d at 25 °C, cream to grey (oac844), reverse oac772 to oac815. Conidiogenous cells monophialidic, arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck, (9–)10.5–17.5(–21) µm long, 2–3.2(–4) µm wide at the base, 1–1.5 µm wide at tip with warty surface. Conidia hyaline, one-celled, fusiform, (5–)6.5–8.5(–10) × 1–2 µm. with mucous sheath.

Colonies on PSA, attaining a diam. of 10 mm within 20 d at 25 °C, (oac841) to (oac843), reverse (oac868). Conidiogenous cells monophialidic cells arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck, (10–)12–16.5(–19) µm long, 2–3 µm wide at the base, 1–1.5 µm wide at tip with warty surface. Conidia hyaline, one-celled, arising from phialides, fusiform, (6–)6.5–8(–8.5) × 1.5–2.5(–3) µm with mucous sheath.

Colonies on SDYA/4, attaining a diam. of 10 mm within 20 d at 25 °C, oac844, reverse oac722 in middle to oac815. Conidiogenous cells monophialidic cells arising from hyphae laterally or terminally, hyaline, tapering gradually or abruptly into a long slender neck, (13–)17–25.5(–30) µm long, (3–)3.5–4 µm wide at the base, 1 µm wide at tip with warty surface. Conidia hyaline, one-celled, arising from phialides, fusiform, (6–)7.5–9(–10) × 1–2 µm with mucous sheath.

Distribution

Thailand.

Ecology

Parasitic on a pair of termites from a reproductive caste (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae) and these specimens were buried in the soil. The fungus emerged from the segment between the prothorax and mesothorax of one of the termite pairs.

Additional specimens examined

THAILAND. Chanthaburi Province, Khao Soi Dao Wildlife Sanctuary; 13°136'N, 102°218'E; on termite; 8 June 2011; K. Tasanathai, P. Srikitikulchai, S. Mongkolsamrit, A. Khonsanit, K. Sansatchanon (BBH31259, BCC 48879).

Notes

Like O. communis and O. pseudocommunis, this species shows similarity to O. rhizoidea. However, von Hohnel’s description of the host in O. rhizoidea was a Coleoptera larva. O. rhizoidea has longer and wider asci and ascospores than O. pseudorhizoidea, while in O. communis and O. pseudocommunis, they are distinctly longer (Table 2).

Table 2.

Morphological comparisons of closely related Ophiocordyceps species used in this study

Species Host Stromata (cm) Perithecia (µm) Asci (µm) Ascospores (µm) Reference
Ophiocordyceps asiatica Termites solitary, simple, filiform, up to 15 long orange brown superficial, globose to subglobose 240–320 × 180–260 filiform 92.5–175 × 5–6.3 whole with septate 90–132.5 × 1–2 This study
Ophiocordyceps brunneirubra Termites solitary, simple or branched, narrowly clavate, slender and wiry, 9.5 cm long, orange brown to red brown Immersed, ovoid, 300–400 × 130–200 cylindrical, 155–225 × 4.5–8 filiform, whole with septate, 156.5–197.5 × 2–3 This study
Ophiocordyceps khokpasiensis Termites solitary, simple cylindrical, 16 cm long, brown pseudo-immersed, subglobose 200–250 × 120–200 filiform, 62.5–125 × 4–5 filiform, whole, 46–90 × 2–3 This study
Ophiocordyceps mosingtoensis Termites solitary simple cylindrical, 11 cm long, brown to grey pseudo-immersed, ovoid 400–500 × 200–300 filiform, 187.5–287.5 × 4.5–7.5 whole with septate, 230–315 × 1.5–3 This study
Ophiocordyceps pseudocommunis Termites solitary simple cylindrical , 21 cm long, brown superficial, subglobose 520–600 × 360–440 filiform, 160–165 × 14–17 whole with 7–8 septa, 107.5–147.5 × 6–7.5 This study
Ophiocordyceps communis Termites solitary simple filiform, 5-13 cm long, yellow brown superficial 285-675 × 195-390 filiform, 215-250 × 15 filiform, whole, 100–180 × 5–6 Sung et al. 2007
Ophiocordyceps pseudorhizoidea Termites solitary, simple, filiform, up to 21 cm long, light brown superficial, ovoid 280–390 × 160–220 cylindrical, 120–150 × 5–7 whole with septate 65–82.5 × 2–3 This study
Ophiocordyceps rhizoidea Coleoptera larva simple, solitary, 7–8 cm long, 0.5-1 mm superficial 360 × 300 160-210 × 13-16 ca 80 × 5-7 von Höhnel, 1909
Ophiocordyceps termiticola Termites solitary, simple, filiform, up to 14 cm long yellow brown pseudo-immersed, globose to subglobose 200–280 × 150–250 filiform 62.5–110 × 4–6 filiform, whole, 85 × 2 This study

Ophiocordyceps termiticola Tasanathai, Noisripoom & Luangsa-ard, sp. nov.

MycoBank No: MycoBank MB 831296
Figure 8

Typification

THAILAND. Kanchanaburi Province, Khao Laem National Park; 14°746'N, 98°625'E; on termite; 20 June 1995; N.L. Hywel-Jones, R. Nasit, S. Sivichai (holotype BBH5634 dried culture; ex-type living culture, BCC 1920). GenBank: ITS = MH754724, LSU = MH753678, TEF = MK284265, RPB1 = MK214108, RPB2 = MK214094

Figure 8. 

Ophiocordyceps termiticola (BBH5634, BCC 1920) A stroma of fungus emerging from termite B part of stroma showing perithecia C perithecia D ascus E ascospore F phialides with conidia on synnema G conidium H colony on PDA at 20 d obverse and reverse I phialides with conidia on PDA J conidium K–O scanning electron micrographs of phialides with conidia on PDA P colony on PSA at 20 d obverse and reverse Q phialides with conidia on PSA R colony on SDYA/4 at 20 d obverse and reverse S phialides with conidia. Scale bars: 2 cm (A); 1 μm (B, K, O); 100 μm (C); 15 μm (D); 8 μm (E); 5 μm (F, G); 7 mm (H, P, R); 3 μm (I, J, L, M, N, Q, S).

Etymology

termiticola’ referring to the host family, Termitidae.

Description

Stroma solitary, simple, filiform, up to 14 cm long, 1 mm wide, yellow-brown, ca. 6 cm emerging above the leaf litter, ca. 8 cm buried in the soil. Asexual state (Hymenostilbe-like) produced ca. 1 cm at the terminal part of the stroma, grey. Perithecia pseudo-immersed, globose to subglobose, produced on one-third of the terminal part of the stroma ending near the apex, (200–)225–261(–280) × (150–)178–229(–250) µm. Asci 8-spored, filiform, (62.5–)76.5–100.5(–110) × (4–)4.5–5.5(–6) µm. Ascospores whole, filiform, 85 × 2 µm, Asexual state Hymenostilbe-like, conidiogenous cells formed a compact hymenium-like layer and had from two to four denticles at their apices, cylindrical to clavate, (10–)11.5–16(–17) × 3–5(–6) µm. Conidia, hyaline, fusiform 7 × 3 µm.

Culture characteristics

Colonies on PDA, attaining a diam. of 28 mm within 20 d at 25 °C, grey (oac781) to pale grey (oac851). Conidiogenous cells monophialidic to polyphialidic, arising from hyphae laterally, with an inflated base (7–)7.5–10(–11) × (2.5–) 3–3.5(–4) µm. Conidia hyaline, globose, 2.5–3 (–3.5) µm, one-celled with warty surface.

Colonies on PSA, attaining a diam. of 22 mm within 20 d at 25 °C, white to pale grey, cotton-like. Conidiogenous cells monophialidic to polyphialidic, hyaline, smooth, with an inflated base (7–)8–10.5(–13) × 3–4 (–5) µm. Conidia hyaline, globose, (2–)2.7–3.4(–4) µm, one celled with warty surface.

Colonies on SDYA/4, attaining a diam. of 29 mm within 20 d at 25 °C, grey to pale grey (oac851). Conidiogenous cells monophialidic to polyphialidic, hyaline, smooth, with an inflated base (7–)8–10.5(–13) × 3–4 µm. Conidia hyaline, globose, 3–3.5(–4) µm, one-celled with warty surface.

Distribution

Thailand.

Ecology

Parasitic on a pair of termites from a reproductive caste (Order Isoptera: Family Termitidae, Subfamily Macrotermitinae) and these specimens were buried in the soil. The fungus emerged from the segment between the prothorax and mesothorax of one of the termite pairs.

Additional specimens examined

THAILAND. Chanthaburi Province, Khao Soi Dao Wildlife Reserve; 13°136'N, 102°218'E; on termite; 20 June 1996; R. Nasit, S. Sivichai, K. Tasanathai (BBH5179, BCC1770).

Notes

Both O. termiticola and O. khokpasiensis produce pseudo-immersed reddish perithecia on a stroma. In O. termiticola, the perithecia are tightly packed, while in O. khokpasiensis, they are loosely aggregated and the length of the anamorphic layer at the end of the fertile part is longer in the latter.

Discussion

Out of the 230+ species of Ophiocordyceps worldwide, less than 10 species occur on termites. The majority of these species produce cylindrical, wiry to pliant, mostly simple, seldom multiple, stromata. Species found in Africa and Mexico, O. bispora (Cordycepioideus bisporus) and O. octospora (Cordycepioideus octosporus), produce thick-walled, multiseptate ascospores, suggesting an adaptation to the harsh environmental conditions in these countries (Ochiel et al. 1997; Blackwell and Gilbertson 1981, 1984). All termite pathogenic species in Thailand including O. asiatica, O. brunneirubra, O. communis, O. khokpasiensis, O. mosingtoensis, O. pseudocommunis, O. pseudorhizoidea and O. termiticola produce filiform, multiseptate, whole ascospores on predominantly superficial and pseudo-immersed perithecia. The dark to pallidly coloured stroma of these species are cylindrical, wiry and pliant and the anamorph is produced at the terminal part of the stroma, after the fertile part.

Interestingly, our results clearly present Ophiocordyceps species occurring on reproductive castes of termites, especially subterranean termite species in the Family Termitidae, Subfamily Macrotermitinae. All species of subterranean termites construct their nests below ground or build mounds above ground and excavate their foraging tunnel in several ways (Eggleton 2010; Ahmad et al. 2018). Usually, the reproductive caste of termites, i.e. flying termites, includes male and female swarms during mating season at the start of the rainy season. The winged queen emerges from the colony for her nuptial flight or the mating flight, releasing pheromones to attract the males to mate. When the male finds the queen, they do a tandem run that lasts for as long as the pair finds a suitable place to start a new colony, during which they shed their wings. In termites, both male and female are the same size (Howard and Thorne 2010; Ahmad et al. 2018). Specimens of termites might have been infected by Ophiocordyceps species after their nuptial flight, when they bury themselves in the ground to establish a nesting area for starting a new colony.

Fungi represent a silent threat to the termite community. Termites have many predators, such as other amphibians (toads), birds, reptiles (lizards, gecko, snakes), small mammals, rodents and even humans. The percentage of the infection to these reproductive castes may be low in comparison to the individuals in a termite swarm, however, only few survive or evade the imminent threat of arthropods and other animals. Eventually, the number of infections caused by Ophiocordyceps becomes significant when only a few can actually survive to start a new colony.

The number of available morphological characters needed to delimit species in fungi are so limited and this may be an important reason why cryptic species are abundant in Kingdom Fungi, i.e. morphologically indistinguishable biological/phylogenetic units present within taxonomic species (Balasundaram et al. 2015) or, as Bickford et al. (2007) put it: ‘two or more distinct species that are erroneously classified (and hidden) under one species name’. Many species of entomopathogenic fungi in Ophiocordycipitceae belong to species complexes or are cryptic species. Zombie ant pathogens in Ophiocordyceps have all been classified as Ophiocordyceps unilateralis sensu lato until morphological and molecular studies, including host identification, were completed (Araujo et al. 2015, 2018; Luangsa-ard et al. 2010; Kobmoo et al. 2012, 2015). The use of DNA-based molecular analyses has subsequently uncovered several new species in the genus (Khonsanit et al. 2018; Luangsa-ard et al. 2018). In culture, the conidiogenous cells of these termite pathogens produce phialides that are either monophialidic or have several lateral necks. The anamorphs of these species do not always form Hirsutella asexual states but more of an intermediate between Hirsutella and Hymenostilbe. This could either be a transition into a different genus or forming a diverging lineage in Ophiocordyceps – in the process of a speciation event or that the production of these anamorphs are so plastic that they cannot be used in taxonomy.

The knowledge that Ophiocordyceps species infect reproductive castes of termites can be used as basic information to study the biological control of subterranean termite pests and to better implement them. All specimens of termites collected are subterranean termites and produce relatively fast growing synnemata with numerous infectious propagules (ascopores) which can be developed further for biological control strategies.

Acknowledgements

The authors are grateful to Platform Technology Management Section, National Center for Genetic Engineering and Biotechnology (BIOTEC), Grant No. P19-50231 and CPMO Grant No. P15-51452 for their support of the biodiversity studies of invertebrate-pathogenic fungi in Thailand. We thank the Department of National Parks for their kind support and permission to collect fungi in the national parks. We also thank Suchada Mongkolsamrit for her help in collecting fungi. This study was supported by National Science and Technology Development Agency (NSTDA). We are grateful to the reviewers whose comments and suggestions helped improve our manuscript.

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