Molecular reassessment of diaporthalean fungi associated with strawberry, including the leaf blight fungus, Paraphomopsis obscurans gen. et comb. nov. (Melanconiellaceae)

A Phylogenetic and Taxonomic Revision of Discula theae-sinensis, the Causal Agents of Anthracnose on Camellia sinensis

Tea (Camellia sinensis (L.) Kuntze) is one of the most important economic plants in China, and has many benefits for human health. Anthracnose is one of the most serious diseases of tea in China, and control of the fungus is important since most Chinese cultivars are susceptible to it. The agent of tea anthracnose was initially described as Gloeosporium theae-sinensis I. Miyake in Japan, which was later transferred to Discula, but this taxonomic position remains problematic. To shed light on these taxonomic and phylogenetic issues, the tea anthracnose pathogens were re-studied. Combining the morphological characteristics and a multigene phylogenetic analysis of nrITS, nrLSU, rpb2, and tef1 sequence data, a new genus Sinodiscula was proposed to accommodate the causal fungi of tea anthracnose, including a new species Sinodiscula camellicola and a new combination Sinodiscula theae-sinensis. Furthermore, the pathogenicity of the pathogens was determined according to Koch's postulates. This study thoroughly resolves the long-standing taxonomic and phylogenetic problems of the tea anthracnose pathogens.

Research on the isolation and identification of black spot disease of Rosa chinensis in Kunming, China

Through a survey of rose diseases in the South Tropical Garden in Kunming, China, it was found that black spot was the most common and serious disease of rose cultivated in the open air there, with an incidence of more than 90%. In this study, fungus isolation was performed on leaf samples of five black spot susceptible varieties of rose from the South Tropical Garden by tissue isolation. 18 strains of fungus were initially obtained, and seven of them were finally identified to cause black spot symptoms on healthy leaves of rose after verification by Koch's rule. By observing the morphology of colonies and spores, and constructing a phylogenetic tree by combining molecular biology and multiple genes, two pathogenic fungus were identified, namely, Alternaria alternata and Gnomoniopsis rosae. G. rosae was the first pathogenic fungi of rose black spot isolated and identified in this study. The results of this study can provide a reference base for further research and control of the black spot disease of rose in Kunming.

Phaeotubakialithocarpicola gen. et sp. nov. (Tubakiaceae, Diaporthales) from leaf spots in China

Tubakiaceae represents a distinct lineage of Diaporthales, including its type genus Tubakia and nine additional known genera. Tubakiaceous species are commonly known as endophytes in leaves and twigs of many tree species, but can also be plant pathogens causing conspicuous leaf symptoms. In the present study, isolates were obtained from diseased leaves of Lithocarpusglaber collected in Guangdong Province, China. The identification was conducted based on morphology and phylogeny of combined loci of 28S nrRNA gene (LSU), internal transcribed spacer regions and intervening 5.8S nrRNA gene (ITS) of the nrDNA operon, translation elongation factor 1-alpha (tef1) and beta tubulin (tub2). As a result, a distinct clade in Tubakiaceae was revealed named Phaeotubakialithocarpicola gen. et sp. nov., which was distinguished from the other tubakiaceous taxa by its dark brown conidiogenous cells and conidia.

Morphological and Phylogenetic Analyses Reveal Four New Species of Gnomoniopsis (Gnomoniaceae, Diaporthales) from China

The fungal genus Gnomoniopsis (Gnomoniaceae, Diaporthales) has been reported all around the world and isolated from multiple plant hosts. Based on multilocus phylogenies from a combined dataset of internal transcribed spacer (ITS) region, the ribosomal RNA gene cluster, and partial regions of translation elongation factor 1 alpha (tef1) and partial beta-tubulin (tub2), in conjunction with morphological characteristics, we describe and illustrate herein four new species, including Gnomoniopsisdiaoluoshanensis sp. Nov., G. lithocarpi sp. Nov., G. mengyinensis sp. Nov. and G.yunnanensis sp. Nov. Alongside this, their similarity and dissimilarity to morphologically-allied and phylogenetically-related species are annotated and discussed. For facilitating future identification, we update the key to all species currently recognized in this genus.

Pseudocryphonectriaelaeocarpicola gen. et sp. nov. (Cryphonectriaceae, Diaporthales) causing stem blight of Elaeocarpus spp. in China

Cryphonectriaceae is a diaporthalean family containing important plant pathogens of which Cryphonectriaparasitica is the most notorious one. An emerging stem blight disease on Elaeocarpusapiculatus (Elaeocarpaceae) and E.hainanensis was observed in Guangdong Province of China recently. Typical Cryphonectria blight-like symptoms including cankers on tree barks with obvious orange conidial tendrils were observed. Forty-eight isolates were obtained from diseased tissues and conidiomata formed on the hosts E.apiculatus and E.hainanensis. These isolates were further identified based on both morphology and molecular methods using the combined sequence data of the internal transcribed spacer (ITS) region, large subunit of the nrDNA (LSU), the translation elongation factor 1-alpha (tef1) and DNA-directed RNA polymerase II second largest subunit (rpb2) genes. As a result, the fungus represents an undescribed genus and species within the family Cryphonectriaceae. Hence, Pseudocryphonectriaelaeocarpicola gen. et sp. nov. is proposed herein to represent these isolates from diseased barks of E.apiculatus and E.hainanensis. Pseudocryphonectria differs from the other genera of Cryphonectriaceae in having dimorphic conidia. Further inoculation results showed that P.elaeocarpicola is the causal agent of this emerging blight disease in China, which can quickly infect and kill the hosts E.apiculatus and E.hainanensis.

Morphology and Phylogeny of Gnomoniopsis (Gnomoniaceae, Diaporthales) from Fagaceae Leaves in China

Gnomoniopsis (Gnomoniaceae, Diaporthales) is a well-classified genus inhabiting leaves, branches and fruits of the hosts in three plant families, namely Fagaceae, Onagraceae and Rosaceae. In the present study, eighteen Gnomoniopsis isolates were obtained from diseased leaves of Fagaceae hosts collected from Fujian, Guangdong, Hainan, Henan, Jiangxi and Shaanxi provinces in China. Morphology from the cultures and phylogeny based on the 5.8S nuclear ribosomal DNA gene with the two flanking internally transcribed spacer (ITS) regions, the translation elongation factor 1-alpha (tef1) and the beta-tubulin (tub2) genes were employed to identify these isolates. As a result, seven species were revealed, viz. Gnomoniopsis castanopsidis, G. fagacearum, G. guangdongensis, G. hainanensis, G. rossmaniae and G. silvicola spp. nov, as well as a known species G. daii. In addition, G. daii was firstly reported on the host Quercus aliena.