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 <i>Chaetomiaceae</i> could serve as potential agents for controlling plant diseases and developing bioorganic fertilizers. Eight species from five genera of <i>Chaetomiaceae</i> were identified from healthy <i>Astragalus sinicus</i> and <i>Vicia villosa</i>, two major cover crops, through multigene phylogenetic analysis, morphological identification, and pairwise homoplasy index testing. The identified species comprise three new species: <i>Achaetomium astragali</i>, <i>Subramaniula henanensis</i>, and <i>S. sichuanensis</i>, as well as five known but new host record species: <i>Botryotrichum murorum</i>, <i>Chaetomium coarctatum</i>, <i>C. pseudocochliodes</i>, <i>C. pseudoglobosum</i>, and <i>Collariella pachypodioides</i>. Dual culture tests revealed that isolates of all eight <i>Chaetomiaceae</i> species exhibited antagonistic effects on multiple phytopathogens. Among the identified fungi, the NSJA2 isolate, belonging to <i>C. coarctatum</i>, 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.