The cytokinin-activated transcription factor ARR2 promotes plant immunity via TGA3/NPR1-dependent salicylic acid signaling in Arabidopsis.
Cytokinins affect plant immunity to various pathogens; however, the mechanisms coupling plant-derived cytokinins to pathogen responses have been elusive. Here, we found that plant-derived cytokinins promote resistance of Arabidopsis to Pseudomonas syringae pv. tomato DC3000 (Pst). Modulated cytokinin levels or signaling activity in CKX- or IPT-overexpressing plants or in ahk2 ahk3 mutants correlated with altered resistance. In fact, the cytokinin-activated transcription factor ARR2 contributes specifically to Pst resistance. The salicylic acid (SA) response factor TGA3 binds ARR2, and mutation of TGA-binding cis-elements in the Pr1 promoter abolished cytokinin- and ARR2-dependent Pr1 activation. Cytokinin treatment did not increase pathogen resistance in tga3 plants, as the cytokinin-dependent induction of Pr1 was eliminated. Moreover, SA signaling enhanced binding of ARR2/TGA3 to the Pr1 promoter. Taken together, these results show that cytokinins modulate the SA signaling to augment resistance against Pst, a process in which the interaction between TGA3 and ARR2 is important.
Choi
Jaemyung
J
Department of Life Sciences, Pohang University of Science and Technology, Korea.
Huh
Sung Un
SU
Kojima
Mikiko
M
Sakakibara
Hitoshi
H
Paek
Kyung-Hee
KH
Hwang
Ildoo
I
D017360:Arabidopsis / Q000276:immunology* / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D003583:Cytokinins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate; D011401:Promoter Regions, Genetic; D044224:Pseudomonas syringae / Q000472:pathogenicity; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C117139:ARR2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D003583:Cytokinins; D004268:DNA-Binding Proteins; C105496:NPR1 protein, Arabidopsis; C087770:TGA3 protein, Arabidopsis; D014157:Transcription Factors; D020156:Salicylic Acid