Research Article |
Corresponding author: Zefen Yu ( zfyu2021@163.com ) Academic editor: Dominik Begerow
© 2018 Min Qiao, Wenjun Li, Ying Huang, Jianping Xu, Li Zhang, Zefen Yu.
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:
Qiao M, Li W, Huang Y, Xu J, Zhang L, Yu Z (2018) Classicula sinensis, a new species of basidiomycetous aquatic hyphomycetes from southwest China. MycoKeys 40: 1-12. https://doi.org/10.3897/mycokeys.40.23828
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Classicula sinensis, isolated from decaying leaves from Mozigou, Chongqing Municipality, China, is described as a new species. The new species is a member of basidiomycetous aquatic hyphomycetes which represent a small proportion of all aquatic hyphomycetes. This species falls within the genus Classicula (Classiculaceae, Pucciniomycotina) and is closely related to C. fluitans, based on multiple gene sequence analyses. Morphologically, it is characterised by the apical, hyaline, obclavate or navicular conidia with several hair-like lateral appendages and by its holoblastic and monoblastic conidiogenesis, with a flat un-thickened conidiogenous locus. Clamp connections and haustorial branches were often observed in culture.
fresh water fungi, mycoparasites, Pucciniomycotina , taxonomy
Aquatic hyphomycetes constitute a dominant mycoflora on submerged decaying plant debris, both in lotic and lentic systems (
There are more than 8000 known species in the Pucciniomycotina (previously Urediniomycetes) and these comprise about one-third of all described basidiomycetes (
During a study of aquatic hyphomycetes on submerged decaying leaves collected from a stream in south-western China, we encountered two fungi which resembled species in the genus Classicula. Combining the morphological and phylogenetic analyses, we identified that the fungi belonged to Classicula. In this paper, we describe these specimens as a new species and discuss its phylogenetic placement based on the combined sequences of the 18S and 28S rDNA, the internal transcribed spacer regions of rDNA (ITS 1 and 2, including the 5.8S rDNA gene) and the translation elongation factor 1-a (TEF1).
Samples of submerged dicotyledonous plant leaves collected from a stream in Chongqing Municipality were transported to the laboratory in zip-locked plastic bags. The rotten leaves were cut to several 0.5–1.5 × 1–1.5 cm sized fragments in the laboratory and spread on to the CMA medium (20 g cornmeal, 18 g agar, 40 mg streptomycin, 30 mg ampicillin, 1000 ml distilled water). After incubation at 27 °C for about 10 days, a single conidium was isolated and cultivated on CMA in Petri plates using a sterilised toothpick under a BX51 microscope. Morphological observations were made from cultures on CMA after incubation at 27 °C for one week. Pure cultures and a permanent slide were deposited in the Herbarium of the Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming, Yunnan, P.R. China (
The cultures were grown on potato dextrose agar (PDA) and incubated at 27 °C for about 10 days. Fungal mycelia were harvested and transferred to a 2.0 ml Eppendorf tube. Total DNA was extracted using a CTAB method as described by
Three regions of the nuclear ribosomal DNA gene cluster and one nuclear protein-coding genes, translation elongation factor 1a (TEF1) were amplified: Primer pairs ITS4 and ITS5 (
Preliminary BLAST searches with 18S and 28S rDNA gene sequences of the new isolates indicated that they had a close phylogenetic relationship with sequences from the genera Jaculiapora and Naiadella (Classicula). Based on the phylogenetic positions of the two genera, we downloaded 18S, 28S, ITS and TEF1 sequences of representative species of 8 class within Pucciniomycotina, but Cryptomycocolacomycetes and Spiculogloeomycetes were not included as Cryptomycocolacomycetes only includes two known species, Cryptomycocolax abnormis and Colacosiphon filiformis and only 18S rDNA of two species are available. Spiculogloeomycetes only comprises yeast and yeast-like species, which has an affinity to Mixiomycetes within Pucciniomycotina. Based on our main aim of identifying new hyphomycetes species within Classiculomycetes, another 8 classes were chosen to carry out phylogenetic analysis. Four sequences of each representative strain of 8 classes were combined with those from our own cultures. (see Table
Raw sequences were aligned using CLUSTAL W 1.6 (
The species used in the phylogenetic analyses. Also included in the Table are the representative isolate name of each species and the GenBank accession numbers for each of the four analysed gene fragments of each isolate.
Class | Species | Isolate No. | GenBank accession No. | Reference | |||
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ITS | 28S | 18S | TEF | ||||
Agaricostilbomycetes | Bensingtonia changbaiensis | AS 2.2310 | AY233339 | AY233339 | AY233339 | KJ707751 | Wang et al. 2003; |
Agaricostilbum hyphaenes | CBS 7811 | AF444553 | AF177406 | AY665775 | KJ707749 | Scorzetti et al. 2002; |
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Chionosphaera apobasidialis | CBS 7430 | AF444599 | AF177407 | U77662 | KJ707883 | Scorzetti et al. 2002; |
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Bensingtonia ciliata | AS 2.1945 | AF444563 | AF189887 | D38234 | KF706486 | Scorzetti et al. 2002; |
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Kurtzmanomyces insolitus | JCM 10409 | AF444594 | AF177408 | KJ708424 | KJ707893 | Scorzetti et al. 2002; |
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Sporobolomyces sasicola | AS 2.1933 | AF444548 | AF177412 | AB021688 | KJ707900 | Scorzetti et al. 2002; |
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Mycogloea nipponica | CBS 11308 | KJ778629 | KJ708456 | KJ708370 | KJ707882 |
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Sterigmatomyces elviae | JCM 1602 | AB038053 | KP216512 | KP216516 | KJ707852 |
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Kondoa aeria | CBS 8352 | AF444562 | AF189901 | KJ708417 | KJ707905 | Scorzetti et al. 2002 | |
Cystobasidiomycetes | Bannoa sp. | MP 3490 | DQ631900 | DQ631898 | DQ631899 | DQ631902 | Matheny et al. 2006 |
Naohidea sebacea | CBS 8477 | DQ911616 | DQ831020 | KP216515 | KF706487 |
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Sporobolomyces coprosmae | JCM 8772 | AF444578 | AF189980 | D66880 | KJ707798 | Scorzetti et al. 2002 | |
Sakaguchia dacryoidea | JCM 3795 | AF444597 | AF189972 | D13459 | KP216514 | Scorzetti et al. 2002 | |
Sporobolomyces bischofiae | JCM 10338 | AB035721 | AB082572 | AB035721 | KJ707777 | Hamamoto et al. 2002 | |
Rhodotorula armeniaca | JCM 8977 | AF444523 | AF189920 | AB126644 | KJ707762 | Scorzetti et al. 2002; |
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Occultifur externus | JCM 10725 | AF444567 | AF189910 | AB055193 | KJ707829 | Scorzetti et al. 2002; |
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Cyrenella elegans | CBS 274.82 | KJ778626 | KJ708454 | KJ708360 | KJ707830 |
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Erythrobasidium hasegawianum | AS 2.1923 | AF444522 | AF189899 | D12803 | KJ707776 | Scorzetti et al. 2002; |
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Pucciniomycetes | Chrysomyxa arctostaphyli | CFB22246 | DQ200930 | AY700192 | AY657009 | DQ435789 | Matheny et al. 2007 |
Endocronartium harknessii | CFB22250 | DQ206982 | AY700193 | AY665785 | DQ234567 | Matthias et al. 2004 | |
Helicobasidium mompa | CBS 278.51 | AY292429 | AY254179 | U77064 | EF100614 | Matthias et al. 2004 | |
Platygloea disciformis | IFO32431 | DQ234556 | AY629314 | DQ234563 | DQ056288 | Matheny et al. 2007 | |
Puccinia graminis tritici | CRL75-36-700-3/ECS | AF468044 | AF522177 | AY125409 | XM_003333024 | Weber et al. 2003 | |
Insolibasidium deformans | TDB183-1 | – | AF522169 | AY123292 | – |
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Septobasidium canescens | DUKE:DAH(323) | DQ241446 | DQ241479 | DQ241410 | – | Henket al. 2007 | |
Tritirachiomycetes | Tritirachium oryzae | CBS 164.67 | GQ329853 | KF258732 | JF779647 | JF779645 |
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Tritirachium sp. | CBS 473.93 | JF779664 | JF779649 | JF779650 | JF779651 |
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Tritirachium sp. | CBS 265.96 | JF779668 | JF779652 | JF779653 | - |
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Mixiomycetes | Mixia osmundae | CBS 9802 | DQ831010 | DQ831009 | D14163 | KJ707837 | Matheny et al. 2006 |
Microbotryomycetes | Leucosporidium scottii | JCM 9052 | AF444495 | AF070419 | X53499 | KJ707788 | Scorzetti et al. 2002; |
Sphacelotheca hydropiperis | CBS 179.24 | KJ708463 | KJ708463 | KJ708394 | KJ707807 |
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Microbotryum violaceum | CBS 143.21 | KJ708462 | KJ708462 | KJ708388 | KJ707811 |
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Sporobolomyces bannaensis | AS 2.2285 | AY274824 | AY274823 | KJ708405 | KJ707934 | Zhao et al. 2003 | |
Rhodosporidium babjevae | JCM 9279 | AF444542 | AF070420 | AB073270 | KJ707874 | Scorzetti et al. 2002; |
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Rhodotorula rosulata | CBS 10977 | EU872492 | EU872490 | KJ708384 | KJ707854 |
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Atractiellomycetes | Helicogloea lagerheimii | FO 36341 | – | AY512849 | AY124476 | – |
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Helicogloea variabilis | KW 1540 | – | L20282 | U78043 | – | Berres et al. 1995 | |
Platygloea vestita | DB 1280 | – | AY512872 | AY124480 | – |
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Classiculomycetes | Classicula fluitans | ATCC 64713 | – | AY512838 | AY124478 | – |
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Classicula sinense |
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KY548838 | KY548836 | KY468515 | MG787169 | This study | |
Classicula sinense |
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KY548837 | KY548835 | KY468514 | MG787170 | This study | |
Jaculispora submersa | CCM 8127 | – | AY512853 | AY124477 | – | Schell et al. 2014 | |
Agaricomycotina | Auricularia sp. | AFTOL-ID 676 | DQ200918 | AY634277 | DQ234542 | DQ408144 | Schell et al. 2014 |
Coprinus comatus | AFTOL-ID 626 | AY854066 | AY635772 | AY665772 | AY881026 | Schell et al. 2014 |
In our Bayesian and maximum likelihood analyses (Figure
BLAST searches using the complete ITS regions of our C. sinensis strains (
Phylogenetic tree based on Bayesian analysis of the combined ITS, TEF1, 18S and 28S rDNA sequences. Auricularia sp. and Coprinus comatus of Agaricomycotina are used as outgroups. Clades and taxa are labelled according to
Sinensis refers to the country in which this species was found.
Classicula sinensis differs from C. fluitans by having fusiform conidiogenous cells growing from the hyphae directly.
CHINA. From leaves of an unidentified dicotyledonous plant submerged in a stream, Chongqing Municipality, Mozigou, 29°25'38"N, 107°24'19"E, ca. 750 m elev. Oct 2014, ZeFen Yu,
Colonies on CMA reach about 10 mm diameter after incubating for 7 days at 27 °C. Colony effuse, mycelium partly superficial, partly immersed in substratum, composed of hyaline, branched, thin-walled, septate, smooth, binucleated hyphae, 1.5–4.8 µm wide, often 1.8–2.7 µm wide. Clamp connection and haustorial branches on hyphae present. Haustorial branches with basal clamps, tapering distally or obclavate, 9–14.2 (–16.5) µm long, 1.2–2.6 µm wide, one or two terminal filaments of 3–8.5 × 1.3 µm located on the top of it. Conidiophores absent. Conidiogenous cells fusiform, monoblastic, 7.5–11×2–2.8 µm, attaching directly on the hyphae, solitary or in aggregates of two. Conidia solitary, acrogenous, navicular or obclavate, attenuating upwards, 25–38 (–42) µm long, 3.8–6.2 µm wide, 1.3–3.4 µm wide at the truncate base, (0–) 2–5 (–7) septa appear in those conidia without cytoplasm, with 1–5 (mainly 3–4) lateral appendages, attaching to the upper part of conidia, opposite or verticillate, filiform, smooth, divergent, pendulous or straight (–7) 13–21 (–25) µm long, 0.8–1.2 µm wide, 0–2(–3) septate. Occasionally, 1(–2) appendages also arise from apex of the main axis. Sometimes clamp connections appear at the top of conidia.
Classicula is phylogenetically related to Jaculispora and morphologically similar to the latter. When Jaculispora was established,
C. fluitans is similar to C. sinensis in having haustorial branches and obclavate or navicular conidia with hair-like lateral and apex appendages. However, their conidiophores and conidiogenous cells were totally different. First, C. sinensis has no conidiophore and its conidiogenous cells grow from hyphae directly, while conidiophores of C. fluitans are determinate, micronematous to semi-macronematous. Second, typical conidiogenous cells of C. fluitans are discrete fusiform formed successively, clamped basally, but C. sinensis has no clamps at the base of conidiogenous cells and conidiogenous cells of C. sinensis are integrated, which resemble that of Jaculispora. Besides the main differences described above, conidia of C. fluitans are shorter and wider [(18–)25– 32(–45) × (4–)5–6.5(–9)] than those of C. sinensis, lateral branches of C. fluitans are 2–3, while 4 lateral branches often appear in C. sinensis. Furthermore, coralloid structures were interpreted as appressoria in C. fluitans but were not observed in C. sinensis (
C. sinensis is similar to J. submersa in conidia form, but conidia of the latter grow on the tip of long micronematous conidiophores, while that of C. sinensis grow from conidiogenous cells directly produced on hyphae. Besides, conidia of J. submersa are longer than those of C. sinensis (type strain: 35–55 × 5–7, MFC-12864:35–56 × 4–6 µm). Septa of conidia without cytoplasm were not mentioned in the type strain of J. submerse. In strain MFC-12864, there is a septum obscurely presented at the attenuated part, while conidia of C. sinensis have 3–4 septa after cytoplasm drained out of the conidia.
A combination of morphological and molecular characters was used to establish C. sinensis. Conidiogenous cells of C. sinensis and C. flutitans were sufficiently different to support the molecular data and to suggest the new species. This situation has not been observed often in other fungi of the same genus, thus more isolates belonging to Classiculomycetes are needed to circumscribe genus characteristics of Classicula better and in more detail.
This work was financed by the National Natural Science Foundation Program of PR China (31770026, 31570023). We are grateful to two reviewers for critically reviewing the manuscript and providing helpful suggestions to improve this paper.