The phosphorous deficiency in arable land limits crop production globally. Plants developed a set of coordinated biochemical and developmental responses to cope with Pi deficiency during evolution. One of typical developmental responses to Pi deficiency is the induction of leaf erectness, which reduced the light capture ability and inhibited photosynthesis to conserve Pi in rice. It has been revealed that Pi deficiency induced leaf inclination by regulating the expression of BR pathway genes. However, how canonic BR signaling coordinates Pi deficiency responses in rice lamina joint development was not clear. Understanding mechanism underlying Pi-deficiency-induced leaf inclination enable us to breed new rice cultivars with increased Pi efficiency. Here we reported the molecular mechanism underlying the interaction of phosphorous deficiency-induced and BR-induced leaf inclination. We showed that BR deficiency can attenuate the leaf inclination by compromising Pi deficiency-induced BU1 expression and that constitutively activated or repressed BR signaling resulted in the insensitivity of Pi deficiency-induced leaf inclination. Furthermore, we compared expression profile of WT and BR signaling constitutively activated or repressed transgenic plants under normal and deficient phosphorous conditions by RNA-seq analysis. Our work revealed the complexity of Pi deficiency stress-induced and BR induced leaf inclinations in rice.

中文翻译：

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油菜素类固醇诱导与缺磷诱导水稻叶片倾斜相互作用的分子基础

耕地缺磷限制了全球作物生产。植物在进化过程中发展出一套协调的生化和发育反应来应对磷缺乏。磷缺乏的典型发育反应之一是诱导叶片直立，这会降低光捕获能力并抑制光合作用以保存水稻中的磷。研究表明，缺磷通过调节 BR 通路基因的表达来诱导叶片倾斜。然而，规范的 BR 信号如何协调水稻叶片联合发育中的缺磷反应尚不清楚。了解缺磷引起叶片倾斜的潜在机制使我们能够培育出具有更高磷效率的水稻新品种。在这里，我们报告了缺磷诱导和 BR 诱导的叶片倾斜相互作用的分子机制。我们表明，BR 缺乏可以通过损害 Pi 缺乏诱导的 BU1 表达来减弱叶片倾斜，并且组成性激活或抑制 BR 信号导致 Pi 缺乏诱导的叶片倾斜不敏感。此外，我们通过 RNA-seq 分析比较了正常和缺磷条件下 WT 和 BR 信号传导组成型激活或抑制的转基因植物的表达谱。我们的工作揭示了水稻缺磷胁迫和 BR 引起的叶片倾斜的复杂性。我们表明，BR 缺乏可以通过损害 Pi 缺乏诱导的 BU1 表达来减弱叶片倾斜，并且组成性激活或抑制 BR 信号导致 Pi 缺乏诱导的叶片倾斜不敏感。此外，我们通过 RNA-seq 分析比较了正常和缺磷条件下 WT 和 BR 信号传导组成型激活或抑制的转基因植物的表达谱。我们的工作揭示了水稻缺磷胁迫和 BR 引起的叶片倾斜的复杂性。我们表明，BR 缺乏可以通过损害 Pi 缺乏诱导的 BU1 表达来减弱叶片倾斜，并且组成性激活或抑制 BR 信号导致 Pi 缺乏诱导的叶片倾斜不敏感。此外，我们通过 RNA-seq 分析比较了正常和缺磷条件下 WT 和 BR 信号传导组成型激活或抑制的转基因植物的表达谱。我们的工作揭示了水稻缺磷胁迫和 BR 引起的叶片倾斜的复杂性。