Potential novel role for the Agrobacterium virulence effector protein VirE2 in modulating plant gene expression
S. GELVIN (1), R. Lapham (1), L. Lee (1) (1) Purdue University, U.S.A.

VirE2, an Agrobacterium effector protein, likely coats T-DNA after it enters the plant cell to protect it from degradation and may assist its nuclear import. VIP1 is a host transcription factor that interacts with VirE2. VIP1 localizes to both the cytoplasm and the nucleus, but under stress localizes to the nucleus where it activates defense response genes. VirE2 holds at least a portion of the VIP1 pool outside the nucleus. We hypothesize that in addition to its proposed structural role in T-DNA trafficking, VirE2 also prevents localization of VIP1 to the nucleus during Agrobacterium infection. This results in changes in expression of VIP1 target genes and suppression of defense responses, facilitating transformation. We have investigated this model by placing VirE2 and VIP1 under control of an inducible promoter in Arabidopsis and performing RNAseq analyses under non-induced and induced conditions, and in the presence of Agrobacterium. Previously identified and putative VIP1 target genes were confirmed, as well as a large number of additional genes containing VIP1 response elements (VRE) in their promoters. These genes were up-regulated by induction of VIP1 at early time points. Some genes differentially expressed after VIP1 and/or VirE2 induction are known to be important for transformation and plant defense. We are analyzing plant lines mutant for, or overexpressing, other differentially expressed genes for altered transformation susceptibility.

Abstract Number: S5-4
Session Type: Special Session