title: Regulation of Jasmonate-Induced Leaf Senescence by Antagonism between bHLH Subgroup IIIe and IIId Factors in Arabidopsis.
abstract: Plants initiate leaf senescence to relocate nutrients and energy from aging leaves to developing tissues or storage organs for growth, reproduction, and defense. Leaf senescence, the final stage of leaf development, is regulated by various environmental stresses, developmental cues, and endogenous hormone signals. Jasmonate (JA), a lipid-derived phytohormone essential for plant defense and plant development, serves as an important endogenous signal to activate senescence-associated gene expression and induce leaf senescence. This study revealed one of the mechanisms underlying JA-induced leaf senescence: antagonistic interactions of the bHLH subgroup IIIe factors MYC2, MYC3, and MYC4 with the bHLH subgroup IIId factors bHLH03, bHLH13, bHLH14, and bHLH17. We showed that MYC2, MYC3, and MYC4 function redundantly to activate JA-induced leaf senescence. MYC2 binds to and activates the promoter of its target gene SAG29 (SENESCENCE-ASSOCIATED GENE29) to activate JA-induced leaf senescence. Interestingly, plants have evolved an elaborate feedback regulation mechanism to modulate JA-induced leaf senescence: The bHLH subgroup IIId factors (bHLH03, bHLH13, bHLH14, and bHLH17) bind to the promoter of SAG29 and repress its expression to attenuate MYC2/MYC3/MYC4-activated JA-induced leaf senescence. The antagonistic regulation by activators and repressors would mediate JA-induced leaf senescence at proper level suitable for plant survival in fluctuating environmental conditions.
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Tiancong
authors.identifier: http://orcid.org/0000-0003-1971-2481
authors.initials: T
authors.lastname: Qi
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Jiaojiao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Huang
authors.initials: H
authors.lastname: Huang
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Liu
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Gao
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Yule
authors.identifier: http://orcid.org/0000-0002-4423-6045
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Susheng
authors.identifier: http://orcid.org/0000-0003-3173-9628
authors.initials: S
authors.lastname: Song
authors.affiliation: Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China daoxinlab@tsinghua.edu.cn.
authors.forename: Daoxin
authors.identifier: http://orcid.org/0000-0002-0493-4295
authors.initials: D
authors.lastname: Xie
mesh_terms: D000375:Aging / Q000502:physiology*; D017360:Arabidopsis / Q000254:growth & development* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000502:physiology; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000502:physiology; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D003517:Cyclopentanes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D054883:Oxylipins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000502:physiology*; D018515:Plant Leaves / Q000254:growth & development* / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology; D015534:Trans-Activators / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D003517:Cyclopentanes; D008565:Membrane Proteins; D054883:Oxylipins; D010937:Plant Growth Regulators; D015534:Trans-Activators; C473611:MYC2 protein, Arabidopsis; C473612:MYC3 protein, Arabidopsis; C473613:MYC4 protein, Arabidopsis; C557299:At5g13170 protein, Arabidopsis; C011006:jasmonic acid