Three New Species and Five New Host Records from Chaetomiaceae with Anti-Phytopathogenic Potential from Cover Crops Astragalus sinicus and Vicia villosa.

Cover crops, typically planted during off-seasons and requiring less agronomic manipulation, may provide abundant fungal resources. Certain species of Chaetomiaceae could serve as potential agents for controlling plant diseases and developing bioorganic fertilizers. Eight species from five genera of Chaetomiaceae were identified from healthy Astragalus sinicus and Vicia villosa, two major cover crops, through multigene phylogenetic analysis, morphological identification, and pairwise homoplasy index testing. The identified species comprise three new species: Achaetomium astragali, Subramaniula henanensis, and S. sichuanensis, as well as five known but new host record species: Botryotrichum murorum, Chaetomium coarctatum, C. pseudocochliodes, C. pseudoglobosum, and Collariella pachypodioides. Dual culture tests revealed that isolates of all eight Chaetomiaceae species exhibited antagonistic effects on multiple phytopathogens. Among the identified fungi, the NSJA2 isolate, belonging to C. coarctatum, exhibited significant relative inhibition effects on 14 out of 15 phytopathogens tested in this study, indicating its broad-spectrum antagonistic effects. Additionally, NSJA2 exhibited excellent salt tolerance. Overall, our study has identified multiple fungi with anti-phytopathogens potential, among which NSJA2 exhibits high potential for practical application. This finding paves the way for further exploration and exploitation of NSJA2 as a promising biocontrol agent.