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李不凡, 姜雨彤, 张禹, 张燕洁, 林文慧. 甘蓝型油菜的BR响应及BnBZL2基因的功能分析[J]. 植物科学学报, 2018, 36(6): 824-834. DOI: 10.11913/PSJ.2095-0837.2018.60824
引用本文: 李不凡, 姜雨彤, 张禹, 张燕洁, 林文慧. 甘蓝型油菜的BR响应及BnBZL2基因的功能分析[J]. 植物科学学报, 2018, 36(6): 824-834. DOI: 10.11913/PSJ.2095-0837.2018.60824
Li Bu-Fan, Jiang Yu-Tong, Zhang-Yu, Zhang Yan-Jie, Lin Wen-Hui. Brassinosteroid response of Brassica napus and functional characterization of BnBZL2[J]. Plant Science Journal, 2018, 36(6): 824-834. DOI: 10.11913/PSJ.2095-0837.2018.60824
Citation: Li Bu-Fan, Jiang Yu-Tong, Zhang-Yu, Zhang Yan-Jie, Lin Wen-Hui. Brassinosteroid response of Brassica napus and functional characterization of BnBZL2[J]. Plant Science Journal, 2018, 36(6): 824-834. DOI: 10.11913/PSJ.2095-0837.2018.60824

甘蓝型油菜的BR响应及BnBZL2基因的功能分析

Brassinosteroid response of Brassica napus and functional characterization of BnBZL2

  • 摘要: 对甘蓝型油菜(Brassica napus L.)与拟南芥(Arabidopsis thaliana L.)中保守的油菜素甾醇(Brassinosteroids,BR)信号相关基因进行对比分析,并以甘蓝型油菜品种‘沪油15’为材料,对BR信号通路相关同源基因进行了组织表达分析。结果显示,BR合成基因与信号组分在花和幼嫩种子中表达量更高;低浓度BR处理可以促进幼苗根的生长,高浓度BR处理则起抑制作用;BR合成抑制剂(Brassinozole,BRZ)处理可抑制黑暗条件下幼苗下胚轴的伸长;BR处理可以降低BR合成基因的表达水平,而BRZ处理则相反,表明甘蓝型油菜中BR信号增加能反馈抑制BR的合成。烟草(Nicotiana tabacum L.)瞬时表达实验结果发现,与拟南芥BZR1基因同源的甘蓝型油菜BnBZL2编码蛋白定位在细胞质和细胞核中,BR处理可增加BnBZL2的核定位。蛋白质免疫印迹检测结果显示,BR处理可增加去磷酸化BnBZL2的比例。本研究进一步模拟了拟南芥bzr1-1D功能获得性突变体对BnBZL2蛋白进行点突变(BnBZL2*),并构建载体转化拟南芥,黑暗条件下转基因植株幼苗对BRZ处理不敏感,提示BnBZL2*可提高转基因植株的BR信号水平。本研究结果表明甘蓝型油菜中存在与拟南芥相似且保守的BR信号通路和调控机制。

     

    Abstract: Brassinosteroids (BR) are important phytohormones that regulate plant growth, development, and seed yield. Brassica napus L. is one of the main eatable oil crops in China. Studying BR signaling and regulation of B. napus growth and development can provide clues to increase yield. We compared BR-related genes in B. napus and A. thaliana and analyzed their expression levels in different tissues (using ‘Huyou15’ as material). Results indicated that the key genes involved in BR synthesis and signal transduction pathways were highly expressed in the flower and young seed; seedling root growth was promoted under BR treatment at low concentration but was inhibited at high concentration; and hypocotyl elongation was inhibited under brassinozole (BRZ, a BR biosynthesis inhibitor) treatment in darkness. Furthermore, BR treatment reduced the expression levels of BR synthesis genes, whereas BRZ treatment increased their expression levels, suggesting that BR signaling feedback inhibited the expression of BR biosynthesis genes. Transient expression experiments in tobacco demonstrated that BnBZL2 (BZR1-like gene in B. napus) was localized in the cytoplasm and nucleus, and BR treatment increased the nuclear localization of BnBZL2. Western blotting revealed that BR treatment increased the ratio of dephosphorylated and phosphorylated BnBZL2. The vector of BnBZL2 with point mutations (BnBZL2*, mimicking A. thaliana gain-of-function mutant bzr1-1D) was transformed into A. thaliana and the transgenic plants showed insensitivity to BRZ treatment in darkness, suggesting that BnBZL2* increased BR signaling. Thus, the above results indicated that BR signaling and regulatory mechanisms were conserved in B. napus and A. thaliana.

     

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