Identification of effector candidates in Bipolaris sorokiniana and their expression profile analysis during pathogen-wheat interactions

Abstract

Spot blotch disease, caused by the fungal pathogen Bipolaris sorokiniana, poses a significant threat to global production particularly wheat, and barley due to substantial yield losses. Similar to many fungal pathogens, the infection of host plants heavily depends on the pathogen's ability to secrete effector proteins, which manipulate host defenses and aid disease progression. However, a critical knowledge gap exists in the comprehensive identification and characterization of effector candidates (ECs) in B. sorokiniana, requiring further research efforts. Therefore, study aimed to systematically identify and characterize ECs in B. sorokiniana by conducting pathogenicity tests to confirm disease symptoms on wheat leaves, utilizing a rigorous bioinformatics approach to predict ECs through sequence analysis and structural similarities, and validating effector expression profiles during infection using RNA sequencing (RNA-Seq) and quantitative real-time polymerase chain reaction (qRT-PCR). Pathogenicity testing confirmed the typical symptoms of spot blotch disease upon inoculation with B. sorokiniana. Through bioinformatics analysis, 81 ECs were identified, showing dynamic expression patterns during infection stages. Among these ECs, genes such as Cocsa1|129517, Cocsa1|141231, and Cocsa1|193443 stood out due to their different expression patterns and structural similarities, indicating their potential roles as effectors. This study offers new novel insights into the effector repertoire of B. sorokiniana and its implications for spot blotch disease management. The identified ECs present promising targets for further investigation to clarify their specific roles in fungal virulence and host immune modulation.