Cytokinin Response Factor 2 positively regulates salicylic acid-mediated plant immunity in Arabidopsis thaliana

Tackmin Kwon
2016 Plant Biotechnology  
The phytohormone cytokinin affects various growth and developmental processes and plant immune responses to various pathogens. However, understanding of the molecular mechanism by which cytokinin regulates plant immunity is at the early stage compared to that of growth and development. Therefore, the role of Arabidopsis thaliana CYTOKININ RESPONSE FACTOR2 (AtCRF2) in plant immunity were investigated. AtCRF2 is a plant specific APETALA2 (AP2)/ethylene-responsive factor (ERF) type transcription
more » ... ype transcription factor that is transiently upregulated by cytokinin in a type-B Arabidopsis response regulator (ARR) dependent manner. Arabidopsis transgenic plants overexpressing AtCRF2 showed an accelerated leaf senescence phenotype, but extreme AtCRF2 overexpression was lethal at an early stage of growth with lesionmimic phenotypes in leaves. Moreover, growth of the compatible hemibiotrophic bacterial pathogen, Pseudomonas syringae pv. tomato DC3000, was strongly compromised in transgenic than in wild-type plants. Furthermore, there was a strong correlation between the expressions of AtCRF2 and pathogenesis related (PR) genes. However, the phenotypes of transgenic plants overexpressing AtCRF2 were completely suppressed by expressing bacterial salicylic hydroxylase, NahG. These results suggest that AtCRF2 may enhance salicylic acid (SA) biosynthesis, leading to autoimmune responses and leaf senescence.
doi:10.5511/plantbiotechnology.16.0711a fatcat:at4rcugahzh2vfalba4tikfrcm