Research Article |
Corresponding author: Chengming Tian ( chengmt@bjfu.edu.cn ) Academic editor: Gerhard Rambold
© 2019 Ning Jiang, Qin Yang, Ying-Mei Liang, Chengming Tian.
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:
Jiang N, Yang Q, Liang Y-M, Tian C (2019) Taxonomy of two synnematal fungal species from Rhus chinensis, with Flavignomonia gen. nov. described. MycoKeys 60: 17-29. https://doi.org/10.3897/mycokeys.60.46395
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Rhus chinensis represents a commercially and ecologically important tree species in China, but suffers from canker diseases in Jiangxi Province. Synnemata, pycnidia and ascomata were discovered on cankered tissues. Strains were obtained from single ascospore or conidium within the fruiting bodies and identified based on morphological comparison and the phylogenetic analyses of partial ITS, LSU, tef1 and rpb2 gene sequences. As a result, two species were confirmed to represent two kinds of synnemata. One of these species is described herein as Flavignomonia rhoigena gen. et sp. nov.; and Synnemasporella aculeans is illustrated showing ascomata, pycnidia and synnemata. Flavignomonia is distinguished from Synnemasporella by the colour of the synnematal tips. Additionally, Flavignomonia can be distinguished from the other gnomoniaceous genera by the formation of synnemata.
Diaporthales, Gnomoniaceae, systematics, taxonomy
Many Diaporthales species are important branch canker pathogens, forming acervuli or pycnidia on diseased tissues (
Gnomoniaceae was initially introduced with Gnomonia as the type (
Chinese gall (Rhus chinensis Mill.) has a range of uses as source of medicine, dye and oil, and has a wide distribution in China (
We conducted our fungal collection surveys from April to October in China, and found Rhus chinensis to be one of the major tree species in Jiangxi Province. Twigs, branches and stems were carefully checked, and diseased tissues were cut into small pieces and packed in paper bags. Isolates were obtained by transferring the ascospores or conidial masses from ascomata to sterile PDA plates, incubating at 25 °C until spores germinated. Single germinating spores were transferred onto new PDA plates, which were kept at 25 °C in darkness. Specimens were deposited in the Museum of the Beijing Forestry University (
Recognition and identification of the fungal species on Rhus chinensis was based on fruiting bodies formed on the bark. Ascomata and conidiomata were sectioned by hand using a double-edged blade, and microscopic structures were observed under a dissecting microscope. At least 10 conidiomata/ascomata, 10 asci, and 50 conidia/ascospores were measured to calculate mean and standard deviation. Measurements are reported as maxima and minima in parentheses and the range representing the mean plus and minus the standard deviation of the number of measurements given in parentheses (
Genomic DNA was extracted from colonies grown on cellophane-covered PDA plates using a modified CTAB method (
The preliminary identities of the isolates sequenced in this study were obtained by conducting a standard nucleotide BLAST search using the sequences generated from the above primers of the different genomic regions (ITS, LSU, tef1 and rpb2). The BLAST results showed that three isolates were grouped in the family Gnomoniaceae, and five isolates in the genus Synnemasporella. The phylogenetic analyses for the three gnomoniaceous isolates were conducted based on
MP analysis was run using a heuristic search option of 1000 search replicates with random additions of sequences with a tree bisection and reconnection algorithm. Other calculated parsimony scores were tree length (TL), consistency index (CI), retention index (RI), and rescaled consistency (RC). ML analysis was performed using a GTR site substitution model including a gamma-distributed rate heterogeneity and a proportion of invariant sites (
Strains used in the phylogenetic tree and their culture accession and GenBank numbers. Strains from this study are in bold.
Species | Strains | GenBank numbers | |||
ITS | LSU | tef1 | rpb2 | ||
Alnecium auctum | CBS 124263 | KF570154 | KF570154 | KF570200 | KF570170 |
Ambarignomonia petiolorum | CBS 116866 | EU199193 | AY818963 | NA | EU199151 |
CBS 121227 | EU254748 | EU255070 | EU221898 | EU219307 | |
Amphiporthe tiliae | CBS 119289 | EU199178 | EU199122 | NA | EU199137 |
Anisogramma anomala | 529478 | EU683064 | EU683066 | NA | NA |
Anisogramma virgultorum | 529479 | EU683062 | EU683065 | NA | NA |
Apiognomonia errabunda | AR 2813 | DQ313525 | NG027592 | DQ313565 | DQ862014 |
Apiognomonia veneta | MFLUCC 16-1193 | MF190114 | MF190056 | NA | NA |
Apioplagiostoma populi | 858501 | KP637024 | NA | NA | NA |
Asteroma alneum | CBS 109840 | EU167609 | EU167609 | NA | NA |
Asteroma sp. | Masuya 8Ah9-1 | NA | AB669035 | NA | NA |
Cryptosporella hypodermia | CBS 116866 | EU199181 | AF408346 | NA | EU199140 |
Discula destructiva | MD 254 | AF429741 | AF429721 | AF429732 | NA |
Ditopella biseptata | MFLU 15-2661 | MF190147 | MF190091 | NA | MF377616 |
Ditopella ditopa | CBS 109748 | DQ323526 | EU199126 | NA | EU199145 |
Ditopellopsis sp. | CBS 121471 | EU254763 | EU255088 | EU221936 | EU219254 |
Flavignomonia rhoigena | CFCC 53118 | MK432674 | MK429917 | NA | MK578102 |
CFCC 53119 | MK432675 | MK429918 | NA | MK578103 | |
CFCC 53120 | MK432676 | MK429919 | NA | MK578104 | |
Gnomonia gnomon | CBS 199.53 | DQ491518 | AF408361 | EU221885 | EU219295 |
CBS 829.79 | AY818957 | AY818964 | EU221905 | NA | |
Gnomoniopsis alderdunensis | CBS 125680 | GU320825 | NA | NA | NA |
Gnomoniopsis chamaemori | CBS 803.79 | EU254808 | EU255107 | NA | NA |
Gnomoniopsis racemula | AR 3892 | EU254841 | EU255122 | EU221889 | EU219241 |
Mamianiella coryli | BPI 877578 | EU254862 | NA | NA | NA |
Marsupiomyces quercina | MFLUCC 13-0664 | MF190116 | MF190061 | NA | NA |
Marsupiomyces epidermoidea | MFLU 15-2921 | NA | MF190058 | NA | NA |
Melanconis marginalis | CBS 109744 | EU199197 | AF408373 | EU221991 | EU219301 |
Neognomoniopsis quercina | CBS 145575 | MK876399 | MK876440 | NA | NA |
Occultocarpon ailaoshanense | LCM 524.01 | JF779849 | JF779853 | NA | JF779856 |
LCM 522.01 | JF779848 | JF779852 | JF779862 | JF779857 | |
Ophiognomonia melanostyla | LCM 389.01 | JF779850 | JF779854 | NA | JF779858 |
Ophiognomonia vasiljevae | AR 4298 | EU254977 | EU255162 | EU221999 | EU219331 |
Plagiostoma aesculi | AR 3640 | EU254994 | EU255164 | NA | EU219269 |
Linospora capreae | CBS 372.69 | NA | AF277143 | NA | NA |
Pleuroceras oregonense | AR 4333 | EU255060 | EU255196 | EU221931 | EU219313 |
Pleuroceras pleurostylum | CBS 906.79 | EU255061 | EU255197 | EU221962 | EU219311 |
Phragmoporthe conformis | AR 3632 | NA | AF408377 | NA | NA |
Valsalnicola oxystoma | AR 5137 | JX519561 | NA | NA | NA |
AR 4833 | JX519559 | JX519563 | NA | NA | |
Sirococcus tsugae | AR 4010 | EF512478 | EU255207 | EU221928 | EU219289 |
CBS 119626 | EU199203 | EU199136 | EF512534 | EU199159 | |
Synnemasporella aculeans | CFCC 52094 | MG682086 | MG682026 | MG682066 | MG682046 |
Synnemasporella aculeans | CFCC 53123 | MK432679 | MK429920 | MK578148 | MK578105 |
CFCC 53124 | MK432680 | MK429921 | MK578149 | MK578106 | |
CFCC 53125 | MK432681 | MK429922 | MK578150 | MK578107 | |
CFCC 53126 | MK432682 | MK429923 | MK578151 | MK578108 | |
CFCC 53127 | MK432683 | MK429924 | MK578152 | MK578109 | |
Synnemasporella toxicodendri | CFCC 52097 | MG682089 | MG682029 | MG682069 | MG682049 |
Tenuignomonia styracis | BPI 89278 | NA | LC379288 | LC379282 | LC379294 |
The alignment based on the combined sequence dataset (ITS, LSU, tef1, and rpb2) included 42 in-group taxa and one out-group taxon, comprising 3368 characters in the aligned matrix. Of these, 2201 characters were constant, 224 variable characters were parsimony-uninformative and 943 characters were parsimony informative (282 from the ITS-LSU, 280 from tef1, 381 from rpb2). The MP analysis resulted in nine equally most parsimonious trees with identical tree backbone. The best ML tree (lnL = −20604.0384) was compatible with the MP strict consensus tree, except for unsupported clades in Fig.
Phylogenetic tree based on an ML analysis of a combined DNA dataset of ITS, LSU, tef1 and rpb2 gene sequences for all genera with DNA data and some species of Gnomoniaceae. Bootstrap values ≥ 50 % for MP and ML analyses are presented at the branches. The scale bar represents the number of changes per site.
Flavignomonia is distinguished from Synnemasporella by the orange tips of its synnemata.
Flavignomonia rhoigena C.M. Tian & Q. Yang
The generic name is derived from the colour of synnemata (flavus = yellow) and the genus name Gnomonia.
Sexual morph: not observed. Asexual morph: Conidiomata synnematal. Synnemata long and determinate, growing from host tissue, with brown base and orange tip, straight to curved, parallel, with flat to slightly concave and dark zone of conidiogenous cells and host tissue at their bases. Conidiophores reduced to conidiogenous cells. Conidiogenous cells phialidic, aggregated, hyaline, straight to curved, cylindrical, arranged adjacent to one another at the end of the synnema, producing a single conidium. Conidia cylindrical to oblong, smooth, multiguttulate, hyaline.
Flavignomonia is included in Gnomoniaceae based on DNA sequences data. Flavignomonia is morphologically similar to Synnemasporella in forming synnemata (
Flavignomonia rhoigena can be distinguished from other gnomoniaceous species by the formation of synnemata.
Named after the host genus, Rhus.
Sexual morph: not observed. Asexual morph: Conidiomata synnematal. Synnemata (650–)750–1100 µm high, 150–300 µm diam, determinate, growing from host tissue, with brown base and orange tip, straight to curved, parallel, with flat to slightly concave and dark zone of conidiogenous cells and host tissue at their bases. Conidiophores reduced to conidiogenous cells. Conidiogenous cells (12.5–)16–22(–25) × 2 μm, phialidic, aggregated, hyaline, straight to curved, cylindrical, arranged adjacent to one another at the end of the synnema, producing a single conidium. Conidia cylindrical to oblong, smooth, multiguttulate, hyaline, (5–)5.5–7(–8) × 1.5–2 µm.
On PDA at 25 °C in darkness, initially white, becoming olive-green to black after 3 wk, zonate with 3–4 well defined zones. Conidiomata distributed concentrically over agar surface.
CHINA, Jiangxi Province, Ganzhou City, Xunwu County, 24°52'31.34"N, 115°35'39.53"E, on branches of Rhus chinensis, 14 May 2018, Q. Yang, Y. Liu & Y.M. Liang (holotype
Flavignomonia rhoigena is the type species of Flavignomonia in the family Gnomoniaceae. It can be easily distinguished from the other gnomoniaceous genera by its unique conidiomata (Walker et al. 2004,
Flavignomonia rhoigena on Rhus chinensis (
Sexual morph: See
CHINA, Jiangxi Province, Ganzhou City, Xunwu County, 24°52'31.34"N, 115°35'39.53"E, on branches of Rhus chinensis, 14 May 2018, Q. Yang, Y. Liu & Y.M. Liang (
Synnemasporella aculeans was proposed as a new combination in the new genus Synnemasporella based on the description of Cryptodiaporthe aculeans (
Asexual morphology of Synnemasporella aculeans on Rhus chinensis (
In this study, two diaporthalean species forming synnemata on Rhus chinensis were identified based on morphology and ITS, LSU, tef1, and rpb2 sequence datasets. As a result, Flavignomonia typified with F. rhoigena is proposed as a new genus in Gnomoniaceae for its distinct phylogenic position and distinctive asexual fruiting body, Also, Synnemasporella aculeans strains were successfully isolated from perithecia, pycnidia and synnemata, which was confirmed by molecular data.
Nineteen fungal species have been recorded from the commercially and ecologically important tree species in China, including Cladosporium cladosporioides, Cronartium quercuum, Mycosphaerella fushinoki, Pestalotiopsis diospyri, P. guepinii, P. mangiferae, P. sorbi, Phaeoramularia rhois, Phyllactinia corylea, Ph. rhoina, Pileolaria klugkistiana, Pi. shiraiana, Pseudocercospora rhoina, Ps. toxicodendri, Septoria sp., Tubercularia phyllophila, Uncinula verniciferae, and two synnematal species from branch cankers in this study (
Gnomoniaceae is a globally distributed fungal family on diverse plant hosts (
This study is financed by National Natural Science Foundation of China (Project No.: 31670647). We are grateful to Chungen Piao, Minwei Guo (China Forestry Culture Collection Center (CFCC), Chinese Academy of Forestry, Beijing.