BRANCHED1 Promotes Axillary Bud Dormancy in Response to Shade in Arabidopsis
BRANCHED1 Promotes Axillary Bud Dormancy in Response to Shade in Arabidopsis
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DOI：
10.1105/tpc.112.108480
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发表时间：
2013-03-01
期刊：
影响因子：
11.6
通讯作者：
Cubas, Pilar
中科院分区：
文献类型：
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作者：
Gonzalez-Grandio, Eduardo;Poza-Carrion, Cesar;Cubas, Pilar
植物将红光与远红光比率 (R:FR) 的下降解释为邻近植被即将遮蔽的迹象。这会引发一系列被称为避荫综合症的发育反应。这些反应之一是通过抑制腋芽生长来减少分枝。拟南芥基因 BRANCHED1 (BRC1) 在腋芽中表达，是响应遮荫而抑制分枝所必需的。与野生型植物不同，brc1 突变体在遮荫处理后会长出几个分枝。 BRC1 转录在暴露于低 R:FR 后 4 小时受到正向调节。一致地，BRC1 受到光敏色素 B 的负向调节。对野生型和模拟遮荫处理的 brc1 植物芽的转录分析揭示了 mRNA 水平依赖于 BRC1 的基因组，其中包括一组上调的脱落酸反应基因以及两个细胞周期和核糖体相关下调基因的网络。下调基因的启动子富含 TEOSINTE BRANCHED1、CYCLOIDEA 和 PCF (TCP) 结合位点，表明它们可能受到 TCP 因子的转录调节。其中一些基因对幼苗和芽中的 BRC1 做出反应，支持它们与 BRC1 活性的密切关系。这种反应可以使植物快速适应 R:FR 光比率的波动。
Plants interpret a decrease in the red to far-red light ratio (R:FR) as a sign of impending shading by neighboring vegetation. This triggers a set of developmental responses known as shade avoidance syndrome. One of these responses is reduced branching through suppression of axillary bud outgrowth. The Arabidopsis thaliana gene BRANCHED1 (BRC1), expressed in axillary buds, is required for branch suppression in response to shade. Unlike wild-type plants, brc1 mutants develop several branches after a shade treatment. BRC1 transcription is positively regulated 4 h after exposure to low R: FR. Consistently, BRC1 is negatively regulated by phytochrome B. Transcriptional profiling of wild-type and brc1 buds of plants treated with simulated shade has revealed groups of genes whose mRNA levels are dependent on BRC1, among them a set of upregulated abscisic acid response genes and two networks of cell cycle- and ribosome-related downregulated genes. The downregulated genes have promoters enriched in TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) binding sites, suggesting that they could be transcriptionally regulated by TCP factors. Some of these genes respond to BRC1 in seedlings and buds, supporting their close relationship with BRC1 activity. This response may allow the rapid adaptation of plants to fluctuations in the ratio of R:FR light.