Research Article |
Corresponding author: Jian-Kui Liu ( ljiankui@gmail.com ) Academic editor: George Mugambi
© 2019 Sheng-Nan Zhang, Kevin D. Hyde, E.B. Gareth Jones, Rajesh Jeewon, Ratchadawan Cheewangkoon, Jian-Kui Liu.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Zhang S-N, Hyde KD, Jones EBG, Jeewon R, Cheewangkoon R, Liu J-K (2019) Striatiguttulaceae, a new pleosporalean family to accommodate Longicorpus and Striatiguttula gen. nov. from palms. MycoKeys 49: 99-129. https://doi.org/10.3897/mycokeys.49.30886
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Palms represent the most morphological diverse monocotyledonous plants and support a vast array of fungi. Recent examinations of palmicolous fungi in Thailand led to the discovery of a group of morphologically similar and interesting taxa. A polyphasic approach based on morphology, multi-gene phylogenetic analyses and divergence time estimates supports the establishment of a novel pleosporalean family Striatiguttulaceae, which diversified approximately 39 (20–63) MYA (crown age) and 60 (35–91) MYA (stem age). Striatiguttulaceae is characterized by stromata or ascomata with a short to long neck, trabeculate pseudoparaphyses and fusiform to ellipsoidal, 1–3-septate ascospores, with longitudinal striations and paler end cells, surrounded by a mucilaginous sheath. Multi-gene phylogenetic analysis showed that taxa of Striatiguttulaceae form a well-supported and distinct monophyletic clade in Pleosporales, and related to Ligninsphaeriaceae and Pseudoastrosphaeriellaceae. However, these families can be morphologically demarcated by the slit-like ascomata and extremely large ascospores in Ligninsphaeriaceae and the rather narrow fusiform ascospores in Pseudoastrosphaeriellaceae. Eight strains of Striatiguttulaceae formed two monophyletic sub-clades, which can be recognized as Longicorpus gen. nov. and Striatiguttula gen. nov. Morphologically, the genus Longicorpus can be differentiated from Striatiguttula by its elongated immersed ascomata and fusiform ascospores with relatively larger middle cells and paler end cells. Two new species Striatiguttula nypae and S. phoenicis, and one new combination, Longicorpus striataspora are introduced with morphological details, and phylogenetic relationships are discussed based on DNA sequence data.
6 new taxa, divergence times, Dothideomycetes, epitype, sexual morphs
Fungi associated with palms have been intensively investigated by Hyde and his co-workers (
Ascomycetes from palms are a very diverse assemblage and the best represented family is Xylariaceae (Xylariales, Sordariomycetes), with three commonly recorded genera Anthostomella (Xylariaceae), Linocarpon (Linocarpaceae) and Oxydothis (Oxydothidaceae) (
Nypa fruticans is an ancient palm that grows in brackish water, while Phoenix paludosa is found in the upper parts of mangroves and tolerates salt water, with both occurring in Thailand mangrove sites. In an ongoing study on the taxonomy of fungi occurring on palms, we collected fungi colonizing these two palm hosts from different mangrove sites in Thailand. Interestingly, a group of ascomycetes recovered appears to be new to science based on morphology and multi-gene phylogenetic evidence. The aim of this study was to characterize the novel taxa and investigate their phylogenetic relationships in the order Pleosporales, as well as apply the divergence times as additional evidence, especially in higher taxa ranking, for the establishment of new family Striatiguttulaceae.
Decayed rachides or petioles of Nypa fruticans and Phoenix paludosa were collected from Chanthaburi, Krabi and Ranong provinces in Thailand. The collected specimens were washed under running water and examined via laboratory procedures as outlined by
Fungal genomic DNA was extracted from fresh mycelia scraped from the margin of a colony on PDA that was incubated at 25 °C–28 °C for 30 days, followed by the Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech (Shanghai) Co., Ltd, China) following the manufacturer’s instructions. Two partial rDNA genes and two protein coding genes were used in this study: the large subunit of the nuclear ribosomal RNA genes (LSU), the small subunit of the nuclear ribosomal RNA (SSU), the translation elongation factor 1-alpha (TEF1α) and the second largest subunit of RNA polymerase II (RPB2). The primers used were LR0R and LR5 for LSU (
A concatenated data set of LSU, SSU, TEF1α and RPB2 sequences was used for phylogenetic analyses with the inclusion of reference taxa from GenBank (Table
Taxa used in this study and their GenBank accession numbers. The type species of each genus are marked with superscript T and ex-type strains are in bold.
Taxa | Strain / Culture | GenBank Accession numbers | |||
---|---|---|---|---|---|
LSU | SSU | TEF1α | RPB2 | ||
Acrocordiopsis patilii | BCC28167 | GU479773 | GU479737 | – | GU479812 |
Acrocordiopsis patilii T | BCC28166 | GU479772 | GU479736 | – | GU479811 |
Acuminatispora palmarum | MFLUCC 18-0460 | MH390438 | MH390402 | MH399249 | MH399252 |
Acuminatispora palmarum T | MFLUCC 18-0264 | MH390437 | MH390401 | MH399248 | – |
Aigialus grandis T | BCC18419 | GU479774 | GU479738 | GU479838 | GU479813 |
Aigialus mangrovei | BCC33563 | GU479776 | GU479741 | GU479840 | GU479815 |
Aigialus parvus | BCC 18403 | GU479778 | GU479744 | GU479842 | GU479817 |
Aigialus rhizophorae | BCC 33572 | GU479780 | GU479745 | GU479844 | GU479819 |
Alternaria alternata | CBS 916.96 | DQ678082 | DQ678031 | DQ677927 | DQ677980 |
Amniculicola lignicola T | Ying01 | EF493861 | EF493863 | – | EF493862 |
Anteaglonium abbreviatum T | ANM 925a | GQ221877 | – | GQ221924 | – |
Anteaglonium globosum | ANM 925.2 | GQ221879 | – | GQ221925 | – |
Antealophiotrema brunneosporum T | CBS 123095 | LC194340 | – | LC194382 | LC194419 |
Aquasubmersa japonica | KT 2862 | LC061587 | LC061582 | – | LC194421 |
Aquasubmersa mircensis T | MFLUCC 11-0401 | JX276955 | JX276956 | – | – |
Arthonia dispersa | UPSC2583 | AY571381 | AY571379 | – | – |
Ascocratera manglicola T | BCC 09270 | GU479782 | GU479747 | GU479846 | GU479821 |
Astrosphaeriella fusispora T | MFLUCC 10-0555 | KT955462 | – | – | KT955413 |
Astrosphaeriella neofusispora | MFLUCC 11-0161 | KT955463 | KT955444 | – | KT955418 |
Astrosphaeriella stellata | KT998 | AB524592 | AB524451 | – | – |
Astrosphaeriellopsis bakeriana | MFLUCC 11-0027 | JN846730 | – | – | – |
Astrosphaeriellopsis bakeriana T | CBS 115556 | GU301801 | – | GU349015 | – |
Bimuria novae-zelandiae T | CBS 107.79 | AY016356 | AY016338 | DQ471087 | DQ470917 |
Botryosphaeria dothidea | CMW 8000 | KF766319 | KF766233 | – | – |
Byssothecium circinans T | CBS 675.92 | AY016357 | – | GU349061 | DQ767646 |
Capnodium coffeae | CBS 147.52 | DQ247800 | DQ247808 | DQ471089 | DQ247788 |
Caryospora minima | – | EU196550 | EU196551 | – | – |
Caryospora aquatica | MFLUCC 11-0008 | MH057847 | MH057850 | – | – |
Cladosporium herbarum | CBS 399.80 | DQ678074 | DQ678022 | DQ677918 | DQ677971 |
Cryptocoryneum condensatum | CBS 122629 | LC194351 | LC194309 | LC096139 | LC194433 |
Cryptocoryneum pseudorilstonei | CBS 113641 | LC194364 | LC194322 | LC096152 | LC194446 |
Delitschia chaetomioides | SMH 3253.2 | GU390656 | – | – | – |
Delitschia didyma | UME 31411 | DQ384090 | AF242264 | – | – |
Delitschia winteri | CBS 225.62 | DQ678077 | – | – | DQ677975 |
Dendrographa decolorans | Ertz 5003 (BR) | NG_027622 | AY548809 | – | – |
Didymella exigua T | CBS 183.55 | EU754155 | EU754056 | – | – |
Didymosphaeria rubi-ulmifolii | MFLUCC 14-0023 | KJ436586 | KJ436588 | – | – |
Dissoconium aciculare | CBS 204.89 | GU214419 | GU214523 | – | – |
Dothidotthia aspera | CPC 12933 | EU673276 | EU673228 | – | – |
Dothidotthia symphoricarpi T | CPC 12929 | EU673273 | EU673224 | – | – |
Extremus antarcticus | CCFEE 5312 | KF310020 | – | – | KF310086 |
Fissuroma bambusae | MFLUCC 11-0160 | KT955468 | KT955448 | KT955430 | KT955417 |
Halotthia posidoniae T | BBH 22481 | GU479786 | – | – | – |
Hermatomyces iriomotensis | MAFF 245730 | LC194367 | – | LC194394 | LC194449 |
Hypsostroma caimitalense | GKM 1165 | GU385180 | – | – | – |
Hypsostroma saxicola T | SMH 5005 | GU385181 | – | – | – |
Hysterium angustatum | CBS 236.34 | FJ161180 | GU397359 | FJ161096 | – |
Hysterobrevium smilacis | CBS 114601 | FJ161174 | FJ161135 | FJ161091 | – |
Latorua caligans T | CBS 576.65 | KR873266 | – | – | – |
Latorua grootfonteinensis | CBS 369.72 | KR873267 | – | – | – |
Lecanactis abietina | Ertz 5068 (BR) | AY548812 | AY548805 | – | – |
Longicorpus striataspora T | MFLUCC 18-0267 | MK035988 | MK035973 | MK034428 | MK034436 |
Longicorpus striataspora | MFLUCC 18-0268 | MK035989 | MK035974 | MK034429 | MK034437 |
Longicorpus striataspora | MFLUCC 17-2515 | MK035990 | MK035975 | MK034430 | MK034438 |
Longicorpus striataspora | MFLUCC 17-2516 | MK035991 | MK035976 | MK034431 | MK034439 |
Lepidosphaeria nicotiae | CBS 101341 | DQ678067 | – | – | DQ677963 |
Leptosphaeria doliolum T | CBS 505.75 | GU301827 | GU296159 | GU349069 | – |
Leptoxyphium fumago | CBS 123.26 | GU301831 | GU214535 | GU349051 | GU371741 |
Ligninsphaeria jonesii | GZCC 15-0080 | KU221038 | – | – | – |
Ligninsphaeria jonesii T | MFLUCC 15-0641 | KU221037 | – | – | – |
Lindgomyces cinctosporae | R56-1 | AB522431 | AB522430 | – | – |
Lindgomyces ingoldianus T | ATCC 200398 | AB521736 | AB521719 | – | – |
Lindgomyces rotundatus | KT1096 | AB521740 | AB521723 | – | – |
Lophiostoma macrostomoides | GKM1033 | GU385190 | – | – | – |
‘Lophiotrema’ boreale | CBS 114422 | LC194375 | – | LC194402 | LC194457 |
Lophiotrema lignicola | CBS 122364 | GU301836 | GU296166 | GU349072 | – |
Lophiotrema nucula T | CBS 627.86 | GU301837 | GU296167 | GU349073 | GU371792 |
Macrodiplodiopsis desmazieri T | CPC 24971 | KR873272 | – | – | – |
Massaria anomia | CBS 591.78 | GU301839 | GU296169 | – | GU371769 |
Massaria gigantispora | M26 | HQ599397 | HQ599447 | HQ599337 | – |
Massaria inquinans T | M19 | HQ599402 | HQ599444 | HQ599342 | HQ599460 |
Massarina eburnea T | CBS 473.64 | GU301840 | GU296170 | GU349040 | GU371732 |
Mauritiana rhizophorae T | BCC 28866 | GU371824 | – | GU371817 | GU371796 |
Melanomma pulvis-pyrius T | CBS 124080 | GU456323 | GU456302 | GU456265 | GU456350 |
Murispora rubicunda T | IFRD 2017 | FJ795507 | GU456308 | – | – |
Mycosphaerella graminicola | CBS 292.38 | DQ678084 | DQ678033 | – | DQ677982 |
Neoastrosphaeriella krabiensis T | MFLUCC 11-0025 | JN846729 | JN846739 | – | – |
Neodeightonia palmicola | MFLUCC10-0822 | HQ199222 | HQ199223 | – | – |
Neotestudina rosatii | CBS 690.82 | DQ384107 | DQ384069 | – | – |
Nigrograna mackinnonii T | CBS 674.75 | GQ387613 | – | – | KF015703 |
Nigrograna marina | CY 1228 | GQ925848 | – | – | GU479823 |
Phaeosphaeria oryzae T | CBS 110110 | GQ387591 | GQ387530 | – | KF252193 |
Phoma herbarum T | CBS 276.37 | DQ678066 | DQ678014 | DQ677909 | DQ677962 |
Piedraia hortae var. hortae | CBS 480.64 | GU214466 | AY016349 | – | DQ677990 |
Pleomassaria siparia T | CBS 279.74 | DQ678078 | DQ678027 | – | DQ677976 |
Pleospora herbarum T | CBS 191.86 | DQ247804 | DQ247812 | DQ471090 | DQ247794 |
Polyplosphaeria fusca T | KT 1616 | AB524604 | AB524463 | – | – |
Preussia funiculata T | CBS 659.74 | GU301864 | – | – | – |
Prosthemium orientale | KT1669 | AB553748 | AB553641 | – | – |
Pseudoastrosphaeriella africana | MFLUCC 11-0176 | KT955474 | KT955454 | KT955436 | KT955421 |
Pseudoastrosphaeriella bambusae | MFLUCC 11-0205 | KT955475 | – | KT955437 | KT955414 |
Pseudoastrosphaeriella longicolla | MFLUCC 11-0171 | KT955476 | – | KT955438 | KT955420 |
Pseudoastrosphaeriella thailandensis T | MFLUCC 11-0144 | KT955478 | KT955457 | KT955440 | KT955416 |
Pseudotetraploa curviappendiculata T | HC 4930 | AB524608 | AB524467 | – | – |
Quadricrura septentrionalis T | HC 4984 | AB524616 | AB524475 | – | – |
Racodium rupestre | L346 | EU048583 | EU048575 | – | – |
Roccella fuciformis | Tehler 8171 | FJ638979 | – | – | – |
Roussoella nitidula T | MFLUCC 11-0182 | KJ474843 | – | KJ474852 | KJ474859 |
Roussoellopsis macrospora | MFLUCC 12-0005 | KJ474847 | – | KJ474855 | KJ474862 |
Salsuginea ramicola | KT2597.2 | GU479801 | GU479768 | GU479862 | GU479834 |
Salsuginea ramicola T | KT 2597.1 | GU479800 | GU479767 | GU479861 | GU479833 |
Striatiguttula nypae T | MFLUCC 18-0265 | MK035992 | MK035977 | MK034432 | MK034440 |
Striatiguttula nypae | MFLUCC 17-2517 | MK035993 | MK035978 | MK034433 | MK034441 |
Striatiguttula nypae | MFLUCC 17-2518 | MK035994 | MK035979 | MK034434 | – |
Striatiguttula phoenicis T | MFLUCC 18-0266 | MK035995 | MK035980 | MK034435 | MK034442 |
Tetraplosphaeria sasicola T | KT563 | AB524631 | AB524490 | – | |
Trematosphaeria pertusa T | CBS 122371 | FJ201992 | – | – | GU371801 |
Triplosphaeria maxima T | KT 870 | AB524637 | AB524496 | – | – |
Ulospora bilgramii T | CBS 101364 | DQ678076 | DQ678025 | DQ677921 | DQ677974 |
Verruculina enalia T | BCC 18401 | GU479802 | – | GU479863 | GU479835 |
Wicklowia aquatica | AF289-1 | GU045446 | – | – | – |
Wicklowia aquatica T | F76-2 | GU045445 | GU266232 | – | – |
Zopfia rhizophila T | CBS 207.26 | DQ384104 | – | – | – |
Maximum parsimony (MP) analyses were performed using the heuristic search option with 1000 random taxa additions and tree bisection and reconnection (TBR) as the branch-swapping algorithm. All characters were unordered and of equally weight; gaps were treated as missing data. Maxtrees setting was 1000, and zero-length branches were collapsed, and all parsimonious trees were saved. Clade stability was assessed using a bootstrap (BT) analysis with 1000 replicates, each with 10 replicates of random stepwise addition of taxa (
The Bayesian analysis was performed using PAUP v.4.0b10 (
One secondary data and two fungal fossil calibrations were used in this study. The split between Arthoniomycetes and Dothideomycetes was selected as a secondary calibration point referring to previous evolutionary molecular studies (
The multi-gene dataset comprised 113 taxa and 4113 characters after alignment (LSU: 919 bp; SSU: 1245 bp; TEF1α: 929 bp; RPB2: 1020 bp) including gaps. RAxML, MP and Bayesian analyses were conducted and resulted in generally congruent topologies, and the familial assignments are similar to previous work (
RAxML tree of Pleosporales based on analysis of combined LSU, SSU, TEF1α and RPB2 sequence data. Bootstrap values for ML and MP equal to or greater than 75% are placed above and below the branches respectively. Branches with Bayesian posterior probabilities (PP) from MCMC analysis equal or greater than 0.95 are in bold. Newly generated sequences are indicated in red.
The eight newly generated strains clustered together and positioned outside the two suborders (Massarineae and Pleosporineae) of Pleosporales, and formed a well-supported monophyletic clade and represented as a new linage of Pleosporales. The phylogeny also revealed that this clade is close to Ligninsphaeriaceae, Pseudoastrosphaeriellaceae, Testudinaceae and Tetraplosphaeriaceae, and can be recognized as a novel family (Striatiguttulaceae). Furthermore, the eight strains formed two well-supported monophyletic sub-clades, which can be identified as two new genera (Longicorpus and Striatiguttula) with three species (Longicorpus striataspora, Striatiguttula nypae and S. phoenicis).
The maximum clade credibility (MCC) tree with divergence estimates (Figure
Maximum clade credibility (MCC) tree with divergence times estimates for Pleosporales and selected groups in Dothideomycetes, obtained from a Bayesian approach (BEAST) using one secondary and two fossil calibrations. Numbers at nodes indicate posterior probabilities (pp) for node support; bars correspond to the 95% highest posterior density (HPD) intervals. Numbers inside green circles indicate nodes used for calibrations: 1) the split of Arthoniomycetes and Dothideomycetes; 2) Metacapnodiaceae; 3) Margaretbarromyces dictyosporus.
Divergence time estimates of Pleosporales and selected lineages of Dothideomycetes obtained from a Bayesian approach (BEAST) on basis of three calibrations. For each divergence, the median and the 95% highest posterior density (HPD) are provided. Divergence times are provided in millions of years (MYA).
Nodes | Crown group | Divergence times | ||||
This study |
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Crown age | Stem age | Crown age | ||||
1 | Arthoniomycetes-Dothideomycetes | 312 (220–413) | – | 317 | – | 310~320 |
2 | Capnodiales | 195 (131–266) | 269 (196–347) | 147 | 216/ (151–283) | ~120 |
3 | Aigialus | 41 (35–56) | 64 (44–91) | 39 | – | ~50 |
4 | Dothideomycetes | 286 (210–369) | 312 (220–413) | 293 ~(210–370) | 341 (257–425) | 255 (166–344) |
5 | Pleosporales | 206 (148–274) | 221 (158–292) | 211 ~(140–270) | 204 (148–260) | 195 (124–271) |
6 | Striatiguttulaceae | 39 20–63) | 60 (35–91) | – | – | – |
Name refers to the name of the type genus.
Saprobic on palms distributed in mangrove habitats. Sexual morph: Stromata black, scattered to gregarious, immersed beneath host epidermis, and erumpent to superficial, with a papilla or a short to long neck, ampulliform, subglobose or conical, uni-loculate or bi-loculate, coriaceous to carbonaceous, ostiolate, periphysate, papillate, clypeate or not clear, glabrous or somewhat interwoven pale brown hyphae or setae. Peridium composed of several brown to hyaline cell layers. Hamathecium of trabeculate pseudoparaphyses. Asci 8-spored, bitunicate, cylindric-clavate, pedicellate. Ascospores hyaline to brown, uniseriate to biseriate or triseriate, fusiform or ellipsoidal, 1–3-septate, striate, guttulate, with paler end cells and surrounded by a mucilaginous sheath. Asexual morph: Undetermined.
Striatiguttula S.N.Zhang, K.D.Hyde & J.K.Liu.
The family Striatiguttulaceae is introduced to accommodate two new genera Longicorpus and Striatiguttula, characterized by the immersed, and erumpent to superficial stromata, with a papilla or a short to long neck, trabeculate pseudoparaphyses, bitunicate asci, and hyaline to brown, fusiform to ellipsoidal, striate, guttulate, 1–3-septate ascospores, with paler end cells and surrounded by a mucilaginous sheath. Members of Striatiguttulaceae are morphologically similar to the genera Leptosphaeria and Trematosphaeria, but they are phylogenetically distinct and also differ in ascospores characteristics and the latter two have coriaceous, heavily pigmented thick-walled peridium. Multi-gene phylogenetic analyses revealed a close relationship of Striatiguttulaceae to Ligninsphaeriaceae and Pseudoastrosphaeriellaceae. However, Striatiguttulaceae differs from Pseudoastrosphaeriellaceae as the latter has 1–3-septate or 2–5-septate ascospores, which are narrowly fusiform with acute ends and all cells are concolorous. The slit-like ascomata and broad fusiform, 1-septate, rather large ascospores (79–121 × 14–23 µm) in Ligninsphaeriaceae (
Name refers to the striate and guttulate ascospores.
Saprobic on palms which are distributed in mangrove habitats. Sexual morph: Stromata black, scattered to gregarious, immersed beneath host epidermis, and erumpent to superficial, with a papilla or a short to long neck, ampulliform, subglobose or conical, uni-loculate or bi-loculate, coriaceous to carbonaceous, ostiolate, periphysate, papillate, clypeate or not, glabrous or somewhat interwoven pale brown hyphae or setae, lying at apex of the neck. Peridium thin, composed of several pale brown to hyaline angular cells. Wall of the neck having elongated angular cells. Hamathecium filament thin, trabeculate pseudoparaphyses, septate, branched, anastomosing, embedded in a gelatinous matrix. Asci 8-spored, bitunicate, cylindric-clavate, pedicellate, apically rounded, with an ocular chamber. Ascospores hyaline to brown, uniseriate to biseriate or triseriate, fusiform to ellipsoidal, 1–3-septate, constrict, the middle cells slightly swollen towards the central septa, striate, guttulate, end cells slightly paler or not, surrounded by a mucilaginous sheath. Asexual morph: Undetermined.
Striatiguttula nypae S.N.Zhang, K.D.Hyde & J.K.Liu.
The epithet reflects the genus name of the host plant Nypa fruticans, from which the specimens were collected.
THAILAND. Ranong: Ranong, on decayed rachis of Nypa fruticans Wurmb (Arecaceae), 3 December 2016, S.N.Zhang, SNT44 (holotype: MFLU 18–1576; isotype: HKAS 97480; ex-type living culture MFLUCC 18–0265 = GZCC 18–0005).
Saprobic on mangrove palm Nypa fruticans. Sexual morph: Stromata in vertical section 240–380 µm high, 195–385 µm diameter, (x̄ = 318.2 × 289.0 µm, n = 15), black, scattered, gregarious, immersed beneath host epidermis, and erumpent to superficial, with a papilla or short to long neck up to 550 µm, subglobose or conical, uni-loculate or bi-loculate, coriaceous to carbonaceous, ostiolate, periphysate, papillate and clypeate, glabrous or somewhat interwoven pale brown hyphae or with setae, lying at apex of the neck. Peridium 9–16 µm thin, composed of several pale brown to hyaline angular cells, compressed and pallid inwardly. Wall of the clypeus composed of brown cells of textura epidermoidea and dark brown host tissue. Wall of the neck with thicker and elongated angular cells. Hamathecium 1–2 µm wide, trabeculate pseudoparaphyses, septate, branched, filamentous, anastomosing, embedded in a gelatinous matrix. Asci 64–145 × 8–17 µm, (x̄= 106.3 × 13.8 µm, n = 30), 8-spored, bitunicate, fissitunicate, cylindric-clavate, pedicellate, apically rounded, with an ocular chamber. Ascospores 18–26 × 4–6 µm, (x̄ = 22.2 × 5.3 µm, n = 50), hyaline to brown, uniseriate to biseriate or triseriate, fusiform, 1–3-septate, constricted at the central septum, the upper middle cell slightly swollen towards the central septum, straight or slightly curved, striate, guttulate, end cells slightly paler, surrounded by a mucilaginous sheath. Asexual morph: Undetermined.
Striatiguttula nypae (holotype MFLU 18–1576, paratype MFLU 18–1578). a–c Appearance of stromata on host surface d–f vertical section through a stroma g structure of peridium h structure of clypeus near the ostiole, composed of epidermoidea cells and host tissue i ostiole with periphyses j pseudoparaphyses k apex of the neck, with somewhat interwoven pale brown hyphae or setae l–o ascus p–s ascospores t ascospore in India ink and presenting a clear mucilaginous sheath u germinating ascospore v colony on PDA. Scale bars: 500 μm (a), 200 μm (b, c), 100 μm (d–f), 10 μm (g, p–s, u), 20 μm (h, i, l–o, t), 50 μm (k).
Colonies on PDA attaining 15 mm diam. within 21 days at 25 °C under natural light, velvety, centrally raised, greenish grey or greyish olivaceous, reverse dull green or grey olivaceous, with a margin of translucent, milky white to hyaline mycelia.
Thailand. Krabi: near Pali, Mueang Krabi District, on submerged decaying rachis of Nypa fruticans Wurmb (Arecaceae), 30 August 2017, S.N.Zhang, SNT207 (paratype: MFLU 18–1577; living culture MFLUCC 17–2517 = GZCC 18–0006); Thailand. Krabi: near Pali, Mueang Krabi District, on submerged decaying rachis of Nypa fruticans Wurmb (Arecaceae), 30 August 2017, S.N.Zhang, SNT208 (paratype: MFLU 18–1578; living culture MFLUCC 17–2518 = GZCC 18–0007).
Inhabiting Thai mangrove forests, Andaman sea (west) coastline, Thailand.
Striatiguttula nypae varies in ascomatal appearance, mostly immersed beneath the plant surface, sometimes visible as a papilla or dome-shaped area on the plant surface, and becomes erumpent to superficial, with a papilla or a short to long neck. The typical morphological characters of S. nypae are the appearance of stromata, with interwoven pale brown hyphae or setae at the apex of the neck, and the hyaline to brown, 1–3-septate, fusiform ascospores, striate, guttulate, with slightly paler end cells and a mucilaginous sheath. We have compared Striatiguttula nypae to previously encountered species on Nypa fruticans, and several morphologically similar mangrove fungal species. However, the striation of ascospores can be a reliable morphological character to distinguish Striatiguttula nypae from Astrosphaeriella nipicola (
Morphological comparison of three new species to Trematosphaeria lineolatispora, T. mangrovis and T. striataspora.
Taxa | Ascomata | Peridium (µm) | Pseudoparaphyses (µm) | Asci (µm) | Ascospores | References | ||
---|---|---|---|---|---|---|---|---|
Ascomata morphology | (high × diam. μm) | Ascospores morphology | Ascospores size (µm) | |||||
Longicorpus striataspora | Immersed, erumpent, ampulliform, subglobose or conical, CA | 300–500 × 230–560 | 11–15 | 1.5 | 85–160 × 10–17 | Fusiform, 1–3-septate, CC | 24–45 × 7–8.8 | This study |
Striatiguttula nypae | Immersed and erumpent to superficial, subglobose or conical, uni-loculate or bi-loculate, CA | 240–380 × 195–385 | 9–16 | 1–2 | 64–145 × 8–17 | Fusiform, 1–3-septate, CC | 18–26 × 4–6 | This study |
Striatiguttula phoenicis | Immersed, erumpent, ampulliform, subglobose, uni-loculate, CB | 195–580 × 135–390 | 10–24 | 1–2 | 89–141 × 12–18 | Fusiform to ellipsoidal, 1–3-septate, CC but nearly concolorous | 20–29 × 6–10 | This study |
Trematosphaeria lineolatispora K.D. Hyde | Immersed with a flattened base, conical to subglobose, clypeate, ostiolate, papillate | 90–180 × 216–360 | up to 25 | 2–4 | 120–204 × 14–18 | Fusiform, mostly 5-septate; CC | 34–48 × 7–10 |
|
Trematosphaeria mangrovis Kohlm. | Semi-immersed, conical or subglobose, papillate | 380–750 × 450–800 | 64–88 | 1.6–2.2 | 190–220 × 20–22 | Broad fusiform or ellipsoidal, 3-septate, CC but no striations | 30–35.6–41 × 10–11.8–13 (–16.5) |
|
Trematosphaeria striataspora K.D. Hyde | Developing amongst the host cortical cells beneath the host epidermis, ampulliform, subglobose or conical, CA | 176–355 × 352–528 | 42–57 (clypeus), thin-walled | 0.8–2.1 | 99–173 × 11–23 | Fusiform, 3(–6)- septate, CC | 31–38 × 6–9 |
|
The epithet referring to the host on which the fungus was collected.
THAILAND. Ranong: Amphoe Mueang Ranong, Tambon Ngao, on decayed rachis of Phoenix paludosa Roxb. (Arecaceae), 6 December 2016, S.N.Zhang, SNT51 (holotype: MFLU 18–1579; isotype: HKAS 97481; ex-type culture MFLUCC 18–0266 = GZCC 18–0008).
Saprobic on mangrove date palm Phoenix paludosa. Sexual morph: Ascomata in vertical section 195–580 µm high, 135–390 µm diameter, (x̄ = 396.0 × 230.3 µm, n = 15), black, scattered, rarely gregarious, immersed, and erumpent through host epidermis by a papilla or a short neck, ampulliform, subglobose, uni-loculate, coriaceous to carbonaceous, ostiolate, periphysate, papillate, glabrous or somewhat interwoven pale brown hyphae or setae, lying around apex of the neck. Peridium 10–24 µm thin, composed of several pale brown to hyaline cells of textura angularis, compressed and pallid inwardly. Wall of the neck composed thick and elongated angular pale brown to brown cells with hyaline inner layers. Hamathecium of 1–2 µm wide, septate, branched, filamentous, anastomosing, trabeculate pseudoparaphyses, embedded in a gelatinous matrix. Asci 89–141 × 12–18 µm, (x̄ = 120.5 × 15.4 µm, n = 20), 8-spored, bitunicate, fissitunicate, cylindric-clavate, pedicellate, apically rounded, with an ocular chamber. Ascospores 20–29 × 6–10 µm, (x̄ = 24.5 × 7.8 µm, n = 40), hyaline to brown (all cells nearly concolorous), uniseriate to biseriate, fusiform to ellipsoidal, 1–3-septate, constricted at the central septum, the upper middle cell slightly swollen and larger, straight or slightly curved, striate, guttulate, surrounded by an irregular mucilaginous sheath. Asexual morph: Undetermined.
Striatiguttula phoenicis (holotype MFLU 18–1579). a–c Appearance of ascoma on host surface d, e vertical section through an ascoma f ostiole g apex of the neck, with somewhat interwoven pale brown hyphae or setae h structure of peridium i, j pseudoparaphyses k–n asci o–t ascospores u ascospore in India ink and presenting a clear mucilaginous sheath v germinating ascospore w colony on PDA. Scale bars: 500 μm (a), 100 μm (b, c), 200 μm (d, e), 50 μm (f, g), 20 μm (h, k–n), 10 μm (i, j, o–v).
Colonies on PDA attaining 14 mm diam within 21 days at 25 °C under natural light, velvety, centrally raised, greenish grey or greyish olivaceous, reverse dull olivaceous or grey, with a margin of translucent, milky white to hyaline mycelium.
Inhabiting Thai mangrove forests, Andaman sea (west) coastline, Thailand.
The fusiform to ellipsoidal, 1–3-septate ascospores of Striatiguttula phoenicis is similar to those of Trematosphaeria mangrovis, associated with submerged roots of mangrove trees. However, Striatiguttula phoenicis differs from T. mangrovis (
Name refers to the elongated ascomata and ascospores.
Saprobic on mangrove palms. Sexual morph: Ascomata black, scattered to gregarious, immersed, and erumpent through host epidermis by a papilla or a short to long neck, sometimes visible as a slightly raised, dome-shaped area, with a clypeus comprises host tissue and fungal hyphae, ampulliform, subglobose or conical, uni-loculate, coriaceous to carbonaceous, ostiolate, periphysate, papillate, glabrous or somewhat interwoven pale brown hyphae or setae. Peridium composing of pale brown or brown angular cells. Hamathecium of septate, branched, thin, anastomosing trabeculate pseudoparaphyses, embedded in a gelatinous matrix. Asci 8-spored, bitunicate, cylindric-clavate, pedicellate, apically rounded, with an ocular chamber. Ascospores uniseriate to biseriate, hyaline to brown, fusiform, 1–3-septate, the upper middle cell slightly swollen towards the central septum, and the end cells paler and smaller, striate, guttulate, surrounded by a mucilaginous sheath. Asexual morph: Undetermined.
Longicorpus striataspora (K.D.Hyde) S.N.Zhang, K.D.Hyde & J.K.Liu.
Longicorpus differs from Striatiguttula in having elongate, fusiform ascospores with relatively larger middle cells and paler end cells (Figures
Trematosphaeria striataspora K.D.Hyde, Botanical Journal of the Linnean Society 98(2): 142. 1988.
Astrosphaeriella striataspora (K.D.Hyde) K.D.Hyde, Botanical Journal of the Linnean Society 110(2): 97. 1992. Type: North Sumatra. K.D.Hyde (holotype: IMI 312390).
THAILAND. Ranong: Ranong, on decayed rachis of Nypa fruticans Wurmb (Arecaceae), 6 December 2016, S.N. Zhang, SNT93 (epitype designated here: MFLU 18–1580; epi-isotype designated here: HKAS 97479; ex-epitype living culture MFLUCC 18–0267 = GZCC 18–0009).
Saprobic on mangrove palms. Sexual morph: Ascomata in vertical section (including short papilla) 300–500 µm high, 230–560 µm diameter, (x̄ = 405.3 × 376.6 µm, n = 15), long neck up to 1285 µm, black, scattered to gregarious, immersed, and erumpent through host epidermis by a papilla or a short to long neck, sometimes visible as a slightly raised, dome-shaped area, with a clypeus comprises host tissue and fungal hyphae, ampulliform, subglobose or conical, uni-loculate, coriaceous to carbonaceous, ostiolate, periphysate, papillate, glabrous or somewhat interwoven pale brown hyphae or setae, lying at apex of the neck. Peridium 11–15 µm wide, composing of brown to pale brown angular cells, thicker at the rim towards the apex. Hamathecium comprising up to 1.5 µm wide, septate, branched, filamentous, trabeculate, anastomosing pseudoparaphyses, embedded in a gelatinous matrix. Asci 85–160 × 10–17 µm (x̄ = 122.7 × 13.7 µm, n = 22), 8-spored, bitunicate, cylindric-clavate, pedicellate, apically rounded, with an ocular chamber. Ascospores 24–45 × 7–8.8 µm, (x̄ = 34.2 × 7 µm, n = 40), uniseriate to biseriate, hyaline to brown, fusiform, 1–3-septate, the upper middle cell slightly swollen towards the central septate, middle cells larger and longer, end cells paler and smaller, straight or slightly curved, striate, guttulate, surrounded by a mucilaginous sheath. Asexual morph: Undetermined.
Longicorpus striataspora (epitype MFLU 18–1580, epi-paratype MFLU 18–1582). a, b Appearance of ascoma on host surface c–e vertical section through an ascoma, with a clypeus near the ostiole f ostiole with periphyses g apex of the neck, with somewhat interwoven pale brown hyphae or setae h–k ascus l peridium in vertical section m vertical section of the neck, with thicker angular cells n pseudoparaphyses o–r ascospores s ascospore in India ink and presenting a clear mucilaginous sheath t germinating ascospore u, v Colony on PDA. Scale bars: 500 μm (a), 200 μm (b), 100 μm (c–e), 10 μm (f, l, n–t), 50 μm (g), 20 μm (h–k, m).
Colonies on PDA attaining 12 mm diameter within 21 days at 25 °C under natural light, velvety, centrally raised, irregular to circular in shape, greenish grey and mixed with milky white mycelium at the edge of a colony, the reverse dull green or grey olivaceous.
Thailand. Chanthaburi, 12°26'43"N, 102°15'47"E, on rachis of Phoenix paludosa Roxb. (Arecaceae), immersed mangrove mud and water, 25 April 2017, S.N.Zhang, SNT130 (epi-paratype MFLU 18–1581; living culture MFLUCC 18–0268 = GZCC 18–0010); Thailand. Krabi, near Pali, on decayed rachis of Nypa fruticans Wurmb (Arecaceae), immersed mangrove mud and water, 30 August 2017, S.N.Zhang, SNT195 (epi-paratype MFLU 18–1582; living culture MFLUCC 17–2515 = GZCC 18–0011; MFLUCC 17–2516 = GZCC 18–0012).
Inhabiting in Thai mangrove forests, the Andaman sea (west) coastline and the Gulf of Thailand (east).
Longicorpus striataspora was found on two mangrove palm species, Nypa fruticans and Phoenix paludosa. The typical characteristics of L. striataspora are the deeply immersed, carbonaceous ascomata with a long neck, and the striate, guttulate, fusiform, 1–3-septate ascospores, with larger middle cells and relatively smaller and paler end cells, surrounded by a mucilaginous sheath. However, such characteristics are similar to Trematosphaeria spp. (Table
A novel pleosporalean family, Striatiguttulaceae is introduced herein, which has been compared to several morphologically similar genera and species recovered from mangroves. This study introduces three novel species including an epitypification. The use of divergence times as an additional evidence for ranking taxa (especially in higher taxa ranking) has become possible and several studies have been carried out across different fungal groups (
The nature of the pseudoparaphyses (sensu
Considering the ecology of these Striatiguttulaceae species in relation to the mangrove ecosystem, salinity may be an important contributor to their presence.
We are grateful to the grant the Thailand Research Fund for supporting collection and research facilities (Grant No. RSA5980068). Jian-Kui Liu thanks the National Natural Science Foundation of China (NSFC 31600032) and Science and Technology Foundation of Guizhou Province (LH [2015]7061). Kevin D. Hyde would like to thank the Thailand Research Grants (No. RDG6130001 and No. 60201000201). The authors would like to thank the staff of Ngao Mangrove Forest Research Center for their assistance in the sample’s collection. We are also grateful to Dr. Shaun Pennycook (Manaaki Whenua Landcare Research, New Zealand) for advising on fungal nomenclature. Ning-Guo Liu is acknowledged for assisting in molecular experiments. We also thank the University of Mauritius for its support.
Phylogenetic analysis