A Ralstonia solanacearum effector targets TGA transcription factors to subvert salicylic acid signaling.
Peipei QiMengling HuangXuehan HuYing ZhangYing WangPengyue LiShiyun ChenDan ZhangSen CaoWanting ZhuJia-Tao XieJiasen ChengYanping FuDao-Hong JiangXiao YuBo LiPublished in: The Plant cell (2022)
The bacterial pathogen Ralstonia solanacearum causes wilt disease on Arabidopsis thaliana and tomato (Solanum lycopersicum). This pathogen uses type III effectors to inhibit the plant immune system; however, how individual effectors interfere with plant immune responses, including transcriptional reprograming, remain elusive. Here, we show that the type III effector RipAB targets Arabidopsis TGACG SEQUENCE-SPECIFIC BINDING PROTEIN (TGA) transcription factors, the central regulators of plant immune gene regulation, via physical interaction in the nucleus to dampen immune responses. RipAB was required for R. solanacearum virulence on wild-type tomato and Arabidopsis but not Arabidopsis tga1 tga4 and tga2 tga5 tga6 mutants. Stable expression of RipAB in Arabidopsis suppressed the pathogen-associated molecular pattern-triggered reactive oxygen species (ROS) burst and immune gene induction as well as salicylic acid (SA) regulons including RBOHD and RBOHF, responsible for ROS production, all of which were phenocopied by the tga1 tga4 and tga2 tga5 tga6 mutants. We found that TGAs directly activate RBOHD and RBOHF expression and that RipAB inhibits this through interfering with the recruitment of RNA polymerase II. These results suggest that TGAs are the bona fide and major virulence targets of RipAB, which disrupts SA signaling by inhibiting TGA activity to achieve successful infection.
Keyphrases
- type iii
- transcription factor
- immune response
- reactive oxygen species
- binding protein
- escherichia coli
- poor prognosis
- pseudomonas aeruginosa
- staphylococcus aureus
- arabidopsis thaliana
- cell death
- signaling pathway
- dna binding
- long non coding rna
- physical activity
- genome wide
- genome wide identification
- oxidative stress
- plant growth
- cystic fibrosis