Loss of function mutations in WRKY22 and WRKY25 impair stomatal mediated immunity and PTI and ETI responses against Pseudomonas syringae pv. tomato

RAMOS, ROMINA NAHIR; NING ZHANG ; DIANA LAUFF; FELIPE VALENZUELA-RIFFO; CARLOS R FIGUEROA ; GREGORY B MARTIN ; MARINA A. POMBO; HERNÁN G ROSLI

PLANT MOLECULAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2023

0167-4412

Plants defend themselves against pathogens using a two-layered immune system. The frst response, pattern-triggered immunity (PTI), is activated upon recognition of microbe-associated molecular patterns (MAMPs). Virulent bacteria such asPseudomonas syringae pv. tomato (Pst), deliver efector proteins into the plant cell to promote susceptibility. However,some plants possess resistance (R) proteins that recognize specifc efectors leading to the activation of the second response,efector-triggered immunity (ETI). Resistant tomatoes such as Río Grande-PtoR recognize two Pst efectors (AvrPto andAvrPtoB) through the host Pto/Prf complex and activate ETI. We previously showed that the transcription factors (TF)WRKY22 and WRKY25 are positive regulators of plant immunity against bacterial and potentially non-bacterial pathogensin Nicotiana benthamiana. Here, the CRISPR-Cas9 technique was used to develop three knockout tomato lines for either oneor both TFs. The single and double mutants were all compromised in Pto/Prf-mediated ETI and had a weaker PTI response.The stomata apertures in all of the mutant lines did not respond to darkness or challenge with Pst DC3000. The WRKY22and WRKY25 proteins both localize in the nucleus, but we found no evidence of a physical interaction between them. TheWRKY22 TF was found to be involved in the transcriptional regulation of WRKY25, supporting the idea that they are notfunctionally redundant. Together, our results indicate that both WRKY TFs play a role in modulating stomata and are positive regulators of plant immunity in tomato.