Gibberellin regulates shoot branching in the perennial woody plants

• 作 者: Jun Ni Congcong Gao Mao-Sheng Chen Bang-Zhen Pan Kaiqin Ye Mei-Li Zhao Zeng-Fu Xu
• 机 构: Key Laboratory of Tropical Plant Resources and Sustainable Use,Xishuangbanna Tropical Botanical Gard
• 出 处: 2015全国植物生物学大会
• 发表日期: 2015年5期
• 关键词: axillary bud cytokinin gibberellin perennial shoot branching strigolactone

　　Auxin,cytokinin(CK),and strigolactone(SL)interact to regulate shoot branching.CK has long been considered to be the only key phytohormone to promote lateral bud development.Here we report that gibberellin(GA)also acts as a positive regulator in controlling shoot branching in the woody plant Jatropha curcas.We show that GA 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 GA biosynthesis,significantly reduced the promotion of bud outgrowth by CK,suggesting that GA is required for CK-mediated axillary bud development.We further show that GA and CK treatments evoked a shared transcriptomic response in axillary buds,which provides molecular support for the physiological observation that GA and CK collaboratively promote bud outgrowth.In addition,auxin and SL,two types of plant hormones involved in the repression of shoot branching,acted antagonistically to both GA 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(MAX2)encoding an F-box protein in the SL signaling pathway,was repressed by GA and CK treatment.We also provide physiological evidences that GA induces shoot branching in other trees,such as papaya and mulberry,indicating a more complicated regulating network occurs in the control of shoot branching in perennial woody plants.