Induction of Somatic Embryos in Arabidopsis Requires Local YUCCA Expression Mediated by the Down-Regulation of Ethylene Biosynthesis
Induction of Somatic Embryos in Arabidopsis Requires Local YUCCA Expression Mediated by the Down-Regulation of Ethylene Biosynthesis
复制标题
拟南芥体细胞胚的诱导需要乙烯生物合成下调介导的局部 YUCCA 表达
DOI：
10.1093/mp/sss154
复制
发表时间：
2013-07-01
期刊：
影响因子：
27.5
通讯作者：
Zhang, Xian Sheng
中科院分区：
文献类型：
--
作者：
Bai, Bo;Su, Ying Hua;Zhang, Xian Sheng
体细胞胚胎发生是研究早期胚胎发育的细胞和分子机制的重要实验模型。虽然人们早就知道从培养基中去除外源生长素会导致体细胞胚胎发生，但体细胞胚胎发生的机制尚不清楚。在本研究中，我们发现编码生长素生物合成关键酶的YUCCAs （YUCs）在拟南芥SE诱导中是必需的。为了确定介导SE起始的其他因素，我们进行了转录谱分析和基因表达分析。结果表明，在乙烯起始过程中，参与乙烯生物合成及其响应的基因被下调。乙烯水平在SE启动过程中逐渐下降，而乙烯的代谢前体，1-氨基环丙烷-1-羧酸（ACC）或乙烯- overproduction1 （ETO1）突变破坏了SE的诱导，表明乙烯在这一过程中起作用。在组成型三重响应1 （ctr1）突变体中也观察到SE诱导的抑制，其中乙烯信号传导增强。这些结果表明，乙烯生物合成和乙烯响应的下调对SE的诱导都是至关重要的。我们进一步发现乙烯通过抑制YUC表达来干扰SE的起始，YUC表达可能参与了生长素的局部生物合成和随后的生长素分布。我们的研究结果为激素调控的SE起始机制提供了新的信息。
Somatic embryogenesis is an important experimental model for studying cellular and molecular mechanisms of early embryo development. Although it has long been known that removal of exogenous auxin from medium results in somatic embryogenesis, the mechanisms underlying the initiation of somatic embryos (SEs) are poorly understood. In this study, we showed that YUCCAs (YUCs) encoding key enzymes in auxin biosynthesis are required for SE induction in Arabidopsis. To identify other factors mediating SE initiation, we performed transcriptional profiling and gene expression analysis. The results showed that genes involved in ethylene biosynthesis and its responses were down-regulated during SE initiation. Ethylene level decreased progressively during SE initiation, whereas treatment with the metabolic precursor of ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC), or mutation of ETHYLENE-OVERPRODUCTION1 (ETO1) disrupted SE induction, suggesting that ethylene plays a role in this process. Suppression of SE induction was also observed in the constitutive triple response 1 (ctr1) mutant, in which ethylene signaling was enhanced. These results indicate that down-regulation of not only ethylene biosynthesis, but also ethylene response is critical for SE induction. We further showed that ethylene disturbed SE initiation through inhibiting YUC expression that might be involved in local auxin biosynthesis and subsequent auxin distribution. Our results provide new information on the mechanisms of hormone-regulated SE initiation.