Morpho-molecular diversity of Linocarpaceae (Chaetosphaeriales): Claviformispora gen. nov. from decaying branches of Phyllostachys heteroclada

White root rot of Bletilla striata: the pathogen, biological characterization, and fungicide screening

Bletilla striata is an endangered traditional medicinal herb in China. In May 2020, the emergence of white root rot severely impacted the quality and yield of B. striata, affecting about 5% of the plants at plant nurseries of the Chengdu Academy of Agricultural and Forestry Sciences. Through a series of experiments and evaluations, the pathogen was identified as Fusarium solani. This is the first report of B. striata white root rot caused by F. solani in Sichuan, China. To better understand this disease and provide data support for its control, a combination of morphological, molecular characterisation and pathogenicity determination was used in this study for assessment. Meanwhile, the effects of different carbon and nitrogen sources, culture medium, temperature, photoperiod and pH on mycelial growth and spore production of F. solani were investigated. In addition, effective fungicides were screened and the concentration ratios of fungicides were optimized using response surface methodology (RSM). The experimental results showed that sucrose was the optimum carbon source for the pathogen, and the optimum temperature and pH were 25°C and pH 7, respectively, while light did no significant effect. Effective fungicides were screened, among which difenoconazole showed the strongest inhibition with EC50 of 142.773 µg/mL. The optimum fungicide concentration scheme (difenoconazole, pyraclostrobin, and thiophanate-methyl at 395.42, 781.03, and 561.11 µg/mL, respectively) was obtained using response surface methodology (RSM) to improve the inhibition rate of 92.24 ± 0.34%. This study provides basic data for the pathogen characterization of B. striata white root rot and its potential fungicides in Sichuan, China. In addition, the optimal fungicide concentration ratios were obtained through response surface methodology (RSM) optimization, which significantly enhanced the fungicidal effect and provided a scientific basis for the future control of B. striata white root rot.

Morphological and molecular analyses reveal two new species of Microcera (Nectriaceae, Hypocreales) associated with scale insects on walnut in China

The fungal genus Microcera consists of species mostly occurring as parasites of scale insects, but are also commonly isolated from soil or lichens. In the present study, we surveyed the diversity and assess the taxonomy of entomopathogenic fungi in Sichuan Province, China. Two new species of Microcera, viz. M.chrysomphaludis and M.pseudaulacaspidis, were isolated from scale insects colonising walnut (Juglansregia). Maximum Likelihood and Bayesian Inference analyses of ITS, LSU, tef1-α, rpb1, rpb2, acl1, act, tub2, cmdA and his3 sequence data provide evidence for the validity of the two species and their placement in Nectriaceae (Hypocreales). Microcerapseudaulacaspidis primarily differs from similar species by having more septate and smaller cylindrical macroconidia, as well as DNA sequence data. Meanwhile, Microcerachrysomphaludis has elliptical, one-septate ascospores with acute ends and cylindrical, slightly curved with 4-6 septate macroconidia up to 78 µm long. Morphological descriptions with illustrations of the novel species and DNA-based phylogeny generated from analyses of multigene dataset are also provided to better understand species relationships.

Morphology and phylogeny of ascomycetes associated with walnut trees (Juglans regia) in Sichuan province, China

In Sichuan province, walnuts, consisting of Juglans regia, Juglans sigillata, and the hybrid J. regia × J. sigillata, are commercially important edible nuts, and J. regia is the most widespread plant. To date, the diversity and distribution of fungi inhabiting on Juglans have not received enough attention, although there have been studies focusing on pathogens from fruit and stem. In order to update the checklist of fungi associated with Sichuan walnuts, a survey on fungi associated with the three Juglans species from 15 representative regions in Sichuan was conducted. In this article, ten fungi distributed in two classes of Ascomycota (Dothideomycetes and Sordariomycetes) were described based on morpho-molecular analyses, and two novel species, Neofusicoccum sichuanense and Sphaerulina juglandina, a known species of Ophiognomonia leptostyla, and seven new hosts or geographical records of Cladosporium tenuissimum, Diatrypella vulgaris, Helminthosporium juglandinum, Helminthosporium velutinum, Loculosulcatispora hongheensis, Periconia byssoides, and Rhytidhysteron subrufulum were included. Morphological descriptions and illustrations of these fungi are provided.

Bambusicolous Fungi in Pleosporales: Introducing Four Novel Taxa and a New Habitat Record for Anastomitrabeculia didymospora

While conducting a survey of bambusicolous fungi in northern Thailand and southwestern China, several saprobic fungi were collected from dead branches, culms and twigs of bamboos, which were preliminarily identified as species belonging to Pleosporales (Dothideomycetes) based on a morphological approach. Multigene phylogenetic analyses based on ITS, LSU, SSU, rpb2, tef1-α and tub2 demonstrated four novel taxa belonging to the families Parabambusicolaceae, Pyrenochaetopsidaceae and Tetraploasphaeriaceae. Hence, Paramultiseptospora bambusae sp. et gen. nov., Pyrenochaetopsis yunnanensis sp. nov. and Tetraploa bambusae sp. nov. are introduced. In addition, Anastomitrabeculia didymospora found on bamboo twigs in terrestrial habitats is reported for the first time. Detailed morphological descriptions and updated phylogenetic trees of each family are provided herein.

Insight into the Systematics of Novel Entomopathogenic Fungi Associated with Armored Scale Insect, Kuwanaspis howardi (Hemiptera: Diaspididae) in China

This study led to the discovery of three entomopathogenic fungi associated with Kuwanaspis howardi, a scale insect on Phyllostachys heteroclada (fishscale bamboo) and Pleioblastus amarus (bitter bamboo) in China. Two of these species belong to Podonectria: P. kuwanaspidis X.L. Xu & C.L. Yang sp. nov. and P. novae-zelandiae Dingley. The new species P. kuwanaspidis has wider and thicker setae, longer and wider asci, longer ascospores, and more septa as compared with similar Podonectria species. The morphs of extant species P. novae-zelandiae is confirmed based on sexual and asexual morphologies. Maximum likelihood and Bayesian inference analyses of ITS, LSU, SSU, tef1-α, and rpb2 sequence data provide further evidence for the validity of the two species and their placement in Podonectriaceae (Pleosporales). The second new species, Microcera kuwanaspidis X.L. Xu & C.L. Yang sp. nov., is established based on DNA sequence data from ITS, LSU, SSU, tef1-α, rpb1, rpb2, acl1, act, cmdA, and his3 gene regions, and it is characterized by morphological differences in septum numbers and single conidial mass.