title: Gibberellin Promotes Shoot Branching in the Perennial Woody Plant Jatropha curcas.
abstract: Strigolactone (SL), auxin and cytokinin (CK) interact to regulate shoot branching. CK has long been considered to be the only key phytohormone to promote lateral bud outgrowth. Here we report that gibberellin also acts as a positive regulator in the control of shoot branching in the woody plant Jatropha curcas. We show that gibberellin and CK synergistically promote lateral bud outgrowth, and that both hormones influence the expression of putative branching regulators, J. curcas BRANCHED1 and BRANCHED2, which are key transcription factors maintaining bud dormancy. Moreover, treatment with paclobutrazol, an inhibitor of de novo gibberellin biosynthesis, significantly reduced the promotion of bud outgrowth by CK, suggesting that gibberellin is required for CK-mediated axillary bud outgrowth. In addition, SL, a plant hormone involved in the repression of shoot branching, acted antagonistically to both gibberellin and CK in the control of lateral bud outgrowth. Consistent with this, the expression of JcMAX2, a J. curcas homolog of Arabidopsis MORE AXILLARY GROWTH 2 encoding an F-box protein in the SL signaling pathway, was repressed by gibberellin and CK treatment. We also provide physiological evidence that gibberellin also induces shoot branching in many other trees, such as papaya, indicating that a more complicated regulatory network occurs in the control of shoot branching in some perennial woody plants.
authors.affiliation: School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ni
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Gao
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
authors.forename: Mao-Sheng
authors.initials: MS
authors.lastname: Chen
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
authors.forename: Bang-Zhen
authors.initials: BZ
authors.lastname: Pan
authors.affiliation: School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China.
authors.forename: Kaiqin
authors.initials: K
authors.lastname: Ye
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, China zfxu@xtbg.ac.cn.
authors.forename: Zeng-Fu
authors.initials: ZF
authors.lastname: Xu
mesh_terms: D003583:Cytokinins / Q000494:pharmacology*; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000494:pharmacology*; D031286:Jatropha / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D007783:Lactones; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D003583:Cytokinins; D044783:F-Box Proteins; D005875:Gibberellins; D007783:Lactones; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors
keywords: Axillary bud; Bud outgrowth; Cytokinin; Gibberellin; Shoot branching; Strigolactone