Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, 666303, China.
Institute of Technical Biology & Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, 230031, China.
Sci Rep. 2017 Sep 12;7(1):11417. doi: 10.1038/s41598-017-11588-0.
Cytokinin (CK) is the primary hormone that positively regulates axillary bud outgrowth. However, in many woody plants, such as Jatropha curcas, gibberellin (GA) also promotes shoot branching. The molecular mechanisms underlying GA and CK interaction in the regulation of bud outgrowth in Jatropha remain unclear. To determine how young axillary buds respond to GA and 6-benzyladenine (BA), we performed a comparative transcriptome analysis of the young axillary buds of Jatropha seedlings treated with GA or BA. Two hundred and fifty genes were identified to be co-regulated in response to GA or BA. Seven NAC family members were down-regulated after treatment with both GA and BA, whereas these genes were up-regulated after treatment with the shoot branching inhibitor strigolactone. The expressions of the cell cycle genes CDC6, CDC45 and GRF5 were up-regulated after treatment with both GA and BA, suggesting they may promote bud outgrowth via regulation of the cell cycle machinery. In the axillary buds, BA significantly increased the expression of GA biosynthesis genes JcGA20oxs and JcGA3ox1, and down-regulated the expression of GA degradation genes JcGA2oxs. Overall, the comprehensive transcriptome data set provides novel insight into the responses of young axillary buds to GA and CK.
细胞分裂素（CK）是正向调控腋芽伸长的主要激素。然而，在许多木本植物中，如麻疯树，赤霉素（GA）也促进分枝。GA 和 CK 在麻疯树芽伸长调控中的相互作用的分子机制尚不清楚。为了确定幼嫩腋芽对 GA 和 6-苄基腺嘌呤（BA）的反应，我们对 GA 或 BA 处理的麻疯树幼苗的幼嫩腋芽进行了比较转录组分析。鉴定出 250 个基因对 GA 或 BA 的反应是共调控的。处理 GA 和 BA 后，有 7 个 NAC 家族成员下调，而这些基因在处理分枝抑制剂独脚金内酯后上调。细胞周期基因 CDC6、CDC45 和 GRF5 的表达在 GA 和 BA 处理后上调，表明它们可能通过调节细胞周期机制促进芽伸长。在腋芽中，BA 显著增加了 GA 生物合成基因 JcGA20oxs 和 JcGA3ox1 的表达，并下调了 GA 降解基因 JcGA2oxs 的表达。总的来说，全面的转录组数据集为幼嫩腋芽对 GA 和 CK 的反应提供了新的见解。
