Oral: Fungal Genomics
Enhancing our understanding of Fusarium maize stalk rot pathogenesis through gene association subnetwork module analyses
H. ZHANG (1), H. Zhang (2), M. Kim (2), H. Yan (2), B. Yoon (2), W. Shim (2) (1) Texas A&M university, U.S.A.; (2) Texas A&M university, U.S.A.
Fusarium verticillioides is an important stalk rot pathogen of maize. While a select number of genes associated with virulence have been characterized, our knowledge of the genetic network underpinning this mechanism is very limited. Previously, our lab identified a striatin-like protein, Fsr1, that plays a key role in stalk rot pathogenesis. To further characterize genetic networks downstream of Fsr1, we performed RNA-Seq with maize B73 stalks inoculated with F. verticillioides wild type and fsr1 mutant. Datasets were first used to infer F. verticillioides co-expression networks. Subsequently, we used a computationally efficient branch-out technique, along with an adopted probabilistic pathway activity inference method, to identify functional subnetwork modules likely involved in F. verticillioides pathogenicity. Through our analyses, potential pathogenicity-associated subnetwork modules were identified, each consisting multiple interacting genes with coordinated expression patterns, but whose collective activation level is significantly different in the wild type and the mutant. In this study we selected three putative pathogenicity genes, FvSYN1, FvEBP1 and FvCYP1, from three predicted subnetworks. We generated gene-deletion mutants and performed pathogenicity assays. Furthermore, qPCR assays were performed to determine whether these genes serve as a hub gene and impose critical regulatory control on associated genes in each subnetwork.