Acidovorax citrulli Type III Effector Aave_2166 Interacts with a Tobacco WRKY transcription Factor to Triggers Plant Defense
B. ZHAO (1), J. Miao (2), S. Traore (2), D. Kong (2) (1) Virginia Tech, U.S.A.; (2) Virginia Tech, U.S.A.

Bacterial fruit blotch caused by Acidovorax citrulli is one of the most important bacterial diseases of cucurbits worldwide. However, the mechanisms associated with A. citrulli pathogenicity and genetics of host resistance have not been extensively investigated. We demonstrated Nicotiana benthamiana and N. tabacum can be used as surrogate hosts for studying A. citrulli pathogenicity and nonhost resistance triggered by type III-secreted (T3S) effectors. One T3S effector Aave_2166 was identified as a homologue of Xanthomonas effector AvrBsT, which belongs to the wide-distributed YopJ/HopZ effector family. Transient expression of Aave_2166 in N. benthamiana and N. tabacum triggers cell death phenotype. A putative N. benthamiana WRKY transcription factor was identified to be specifically interacted with Aave2166 in yeast-two hybrid and co-immunoprecipitation assays. Aave_2166 can modify NbWRKY in vitro and alter its subcellular localization in vivo. Silencing of NbWRKY through Virus Induced Gene Silencing or knockout it through the CRISPR-Cas9 approach in N. benthamiana suppresses the cell death phenotype triggered by A. citrulli or Aave_2166 expressed by Agrobacterium. Therefore, NbWRKY could be one of molecular targets of Aave2166 and it is required for Aave2166 triggered-immunity in N. benthamiana.

Abstract Number: P17-648
Session Type: Poster