Endophytic Trichoderma (Sordariomycetes, Hypocreaceae) species associated with Citrus in Guangdong province, China

ABSTRACT Trichoderma species are well‐known biocontrol agents for many plant diseases. These species are also associated as endophytes in various hosts. In the present study, endophytic Trichoderma species were isolated from four Citrus species: Citrus reticulata , C. nobilis , C. tachibana , and C. maxima . Isolates were identified based on morphology and multigene phylogenetic analysis based on internal transcribed spacer regions of the ribosomal DNA (ITS), the translation elongation factor 1‐α encoding gene ( tef1‐α ) and the gene encoding the second largest nuclear RNA polymerase subunit ( rpb2 ). In total, 16 isolates were identified as four new species and one known species. Trichoderma reticulatae sp. nov., T. citri sp. nov., T. wujiangense sp. nov. belonging to the Harzianum clade are introduced as new species. From the Atroviride clade, T. nobilis sp. nov. is introduced as a new species and T. koningiopsis belonging to the Viride clade is described as a new host record. A detailed description of the morphology and cultural characteristics of the newly discovered Trichoderma species is provided, and these characteristics were compared with those of closely related species to better understand the taxonomic relationships within the Trichoderma . Our study will provide an account of Trichoderma species associated with various Citrus species in Guangdong, China.