Comparative Transcriptomics and Gene Knockout Reveal Virulence Factors of Arthrinium phaeospermum in Bambusa pervariabilis × Dendrocalamopsis grandis.

ABSTRACT

Arthrinium phaeospermum can cause branch wilting of Bambusa pervariabilis × Dendrocalamopsis grandis, causing great economic losses and ecological damage. A. phaeospermum was sequenced in sterile deionized water (CK), rice tissue (T1) and B. pervariabilis × D. grandis (T2) fluid by RNA-Seq, and the function of Ctf1ß 1 and Ctf1ß 2 was verified by gene knockout. There were 424, 471 and 396 differentially expressed genes between the T2 and CK, T2 and T1, and CK and T1 groups, respectively. Thirty DEGs had verified the change in expression by fluorescent quantitative PCR. Twenty-nine DEGs were the same as the expression level in RNA-Seq. In addition, ΔApCtf1ß 1 and ΔApCtf1ß 2 showed weaker virulence by gene knockout, and the complementary strains Ctf1ß 1 and Ctf1ß 2 showed the same virulence as the wild-type strains. Relative growth inhibition of ΔApCtf1ß 1 and ΔApCtf1ß was significantly decreased by 21.4% and 19.2%, respectively, by adding H2O2 compared to the estimates from the wild-type strain and decreased by 25% and 19.4%, respectively, by adding Congo red. The disease index of B. pervariabilis × D. grandis infected by two mutants was significantly lower than that of wild type. This suggested that Ctf1ß genes are required for the stress response and virulence of A. phaeospermum.