Characterization, Phylogenetic Analyses, and Pathogenicity of Eutiarosporella dactylidis on Sorghum in China

Sorghum, the fifth-largest cereal crop globally and a C4 crop, mainly grows in arid and semi-arid areas. In 2021-2023, a new foliar disease of sorghum occurred in China. The diseased leaves showed water-soaked symptoms in the leaf tip and margins, resulting in half- and full-leaf desiccation and necrosis, thus affecting plant photosynthesis. A total of 24 Eutiarosporella strains were isolated from symptomatic leaves. Based on morphological characteristics and multi-locus phylogenetic analysis involving ITS, LSU, and EF1-α sequences, and the pathogenicity test, the pathogen of sorghum causing leaf blight in China was identified as Eutiarosporella dactylidis. The virulence of all E. dactylidis strains was evaluated using the spray-mycelium method. Different strains showed significantly different pathogenicities toward a susceptible cultivar, Longza 10, with disease indexes ranging from 23.76 to 60.37. This study first reported leaf blight of sorghum caused by E. dactylidis and named it "Eutiarosporella leaf blight", which provides a theoretical basis for farmers in disease management.