Loose Plant Architecture1 (LPA1) determines lamina joint bending by suppressing auxin signalling that interacts with C-22-hydroxylated and 6-deoxo brassinosteroids in rice.
Loose Plant Architecture1 (LPA1) determines lamina joint bending by suppressing auxin signalling that interacts with C-22-hydroxylated and 6-deoxo brassinosteroids in rice.
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DOI：
10.1093/jxb/erw002
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发表时间：
2016-03
影响因子：
6.9
通讯作者：
Han CD
中科院分区：
文献类型：
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作者：
Liu JM;Park SJ;Huang J;Lee EJ;Xuan YH;Je BI;Kumar V;Priatama RA;Raj K V;Kim SH;Min MK;Cho JH;Kim TH;Chandran AK;Jung KH;Takatsuto S;Fujioka S;Han CD
LPA 1抑制生长素信号传导，其与C-22-羟基化和6-脱氧油菜素类固醇相互作用，其独立于OsBRI 1调节叶片倾斜。叶片倾斜度是决定植物构型的关键农艺性状，对生长素和油菜素内酯敏感。水稻LPA 1基因及其拟南芥同源基因SGR 5/AtIDD 15调控植物的构型和生长素的稳态。本研究探讨了LPA 1在决定水稻叶片倾斜度中的作用。LPA 1作为一个积极的调节器，抑制椎板弯曲。遗传和生化数据表明，LPA 1抑制生长素信号，与C-22-羟基化和6-脱氧BR相互作用，调节叶片倾斜独立的OsBRI 1。突变体lpa 1植物在叶片倾斜反应期间对吲哚-3-乙酸（IAA）超敏感，这被参与BR合成的C-22羟化酶的油菜素（Brz）抑制剂抑制。在IAA介导的叶片倾斜过程中，检测到lpa 1和d2（C-23-羟基化BR催化的缺陷突变体）之间的强烈协同效应。LPA 1和OsBRI 1之间没有显著的相互作用。lpa 1突变体对d 61 -1（水稻BRI 1突变体）背景中的C-22-羟基化和6-脱氧BR敏感。我们目前的证据证实，两个独立的途径功能通过BRs或BRI 1，以确定IAA介导的水稻叶片倾斜。RNA测序和qRT-PCR分析表明，LPA 1影响OsPIN 1a、OsPIN 1c和OsPIN 3a基因的表达，表明生长素通量可能是LPA 1介导水稻叶片倾斜的重要因素。
LPA1 suppresses auxin signalling that interacts with C-22-hydroxylated and 6-deoxo brassinosteroids, which regulates lamina inclination independently of OsBRI1. Lamina inclination is a key agronomical character that determines plant architecture and is sensitive to auxin and brassinosteroids (BRs). Loose Plant Architecture1 (LPA1) in rice (Oryza sativa) and its Arabidopsis homologues (SGR5/AtIDD15) have been reported to control plant architecture and auxin homeostasis. This study explores the role of LPA1 in determining lamina inclination in rice. LPA1 acts as a positive regulator to suppress lamina bending. Genetic and biochemical data indicate that LPA1 suppresses the auxin signalling that interacts with C-22-hydroxylated and 6-deoxo BRs, which regulates lamina inclination independently of OsBRI1. Mutant lpa1 plants are hypersensitive to indole-3-acetic acid (IAA) during the lamina inclination response, which is suppressed by the brassinazole (Brz) inhibitor of C-22 hydroxylase involved in BR synthesis. A strong synergic effect is detected between lpa1 and d2 (the defective mutant for catalysis of C-23-hydroxylated BRs) during IAA-mediated lamina inclination. No significant interaction between LPA1 and OsBRI1 was identified. The lpa1 mutant is sensitive to C-22-hydroxylated and 6-deoxo BRs in the d61-1 (rice BRI1 mutant) background. We present evidence verifying that two independent pathways function via either BRs or BRI1 to determine IAA-mediated lamina inclination in rice. RNA sequencing analysis and qRT-PCR indicate that LPA1 influences the expression of three OsPIN genes (OsPIN1a, OsPIN1c and OsPIN3a), which suggests that auxin flux might be an important factor in LPA1-mediated lamina inclination in rice.