Differences in the Characteristics and Pathogenicity of Species Associated with Seeds of Italian Ryegrass.

is a genus of pathogens that cause leaf damage and a common seedborne fungus of Italian ryegrass ( Lam.). To elucidate the main seedborne species, 36 seed samples of Italian ryegrass were collected; in total, 113 strains, representing 12.3% of all isolated strains (921), were identified as species using the identity of ITS sequences in NCBI and the similarity of morphological characteristics. (97) was the most frequent species. By pure culture technique, 24 representative pure isolates were obtained for further study. Based on DNA analysis of multiple loci (ITS, LSU, , , and ) and morphological characters, eight species were identified, , , , , , , , and ; among them, , , and were newly reported on Italian ryegrass worldwide. Seed inoculation showed that , , and remarkably decreased the final germination percentages and germination indexes compared with control treatments ( ≤ 0.05); and plant inoculation showed that , , and could cause typical brown spot in vivo with a higher infection rate ( ≤ 0.05). In conclusion, pathogenicity tests showed that all species could both inhibit seed germination and infect Italian ryegrass to different degrees; among them, was the most important seedborne pathogen based on the combination of its isolation and infection rate, followed by and . The data generated in this study are helpful for the accurate identification of species and the development of seedborne disease management strategies.