The bHLH subgroup IIId factors negatively regulate jasmonate-mediated plant defense and development.
Plants have evolved sophisticated systems for adaptation to their natural habitat. In response to developmental and environmental cues, plants produce and perceive jasmonate (JA) signals, which induce degradation of JASMONATE-ZIM-Domain (JAZ) proteins and derepress the JAZ-repressed transcription factors to regulate diverse aspects of defense responses and developmental processes. Here, we identified the bHLH subgroup IIId transcription factors (bHLH3, bHLH13, bHLH14 and bHLH17) as novel targets of JAZs. These bHLH subgroup IIId transcription factors act as transcription repressors and function redundantly to negatively regulate JA responses. The quadruple mutant bhlh3 bhlh13 bhlh14 bhlh17 showed severe sensitivity to JA-inhibited root growth and JA-induced anthocyanin accumulation, and exhibited obvious increase in JA-regulated plant defense against pathogen infection and insect attack. Transgenic plants overexpressing bHLH13 or bHLH17 displayed reduced JA responses. Furthermore, these bHLH factors functioned as transcription repressors to antagonize the transcription activators, such as MYC2 and the WD-repeat/bHLH/MYB complex, through binding to their target sequences. Coordinated regulation of JA responses by transcription activators and repressors would benefit plants by allowing fine regulation of defense and development, and survival in their frequently changing environment.
Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.
Susheng
S
Song
Tiancong
T
Qi
Meng
M
Fan
Xing
X
Zhang
Hua
H
Gao
Huang
H
Huang
Dewei
D
Wu
Hongwei
H
Guo
Daoxin
D
Xie
D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000276:immunology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D003517:Cyclopentanes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D054883:Oxylipins / Q000378:metabolism*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology; D030821:Plants, Genetically Modified / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D020798:Two-Hybrid System Techniques
D000872:Anthocyanins; D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D012097:Repressor Proteins; C554741:JAZ1 protein, Arabidopsis; C473611:MYC2 protein, Arabidopsis; C011006:jasmonic acid