Study of the role of two tomato WRKY transcription factors in the activation of the ETI response

RAMOS, ROMINA NAHIR; POMBO, MARINA ALEJANDRA; ROSLI, HERNÁN GUILLERMO

Congreso; XXXII RAFV; 2018

Gram-negative pathogenic bacteria introduce effectors in the plant cell to promote disease. However, some plants posses resistance (R) proteins that detect the presence of specific effectors leading to a robust defense response named effector-triggered immunity (ETI). This immune response culminates in a hypersensitive response (HR) that includes the development of programed cell death (PCD), limiting pathogen spread. In resistant tomato plants, the kinase Pto recognizes two Pseudomonas syringae pv. tomato (Pst) effectors (AvrPto and AvrPtoB) and jointly with Prf activate ETI.In a previous work, using an RNAseq approach, we identified two WRKY transcription factors (TF) whose expression is induced specifically when ETI is activated 6 h after bacterial infiltration. Silencing of these genes individually and jointly using virus induced gene silencing (VIGS) technique led to a delay in Pto/AvrPto PCD development in Nicotiana benthamiana (Nb). Similar results were observed when Nb plants were co-infiltrated with different non-bacterial avirulence gene/R protein pairs. Also, reduction in WRKY TF transcripts resulted in plants with more disease symptoms when challenged with Pseudomonas syringae pv. tabaci (AvrPto).Our results confirm the participation of these TF in the activation of bacterial and non-bacterial immune responses.