A high concentration of abscisic acid inhibits hypocotyl phototropism in Gossypium arboreum by reducing accumulation and asymmetric distribution of auxin
A high concentration of abscisic acid inhibits hypocotyl phototropism in Gossypium arboreum by reducing accumulation and asymmetric distribution of auxin
复制标题
高浓度脱落酸通过减少生长素的积累和不对称分布来抑制植物棉的下胚轴向光性
DOI：
10.1093/jxb/erab298
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发表时间：
2021
影响因子：
6.9
通讯作者：
Xiang Zhao
中科院分区：
文献类型：
--
作者：
Jin-Dong Zhu;Jing Wang;Xi-Ning Guo;Bao-Shuan Shang;Hong-Ru Yan;Xiao Zhang;Xiang Zhao
下胚轴向光性是由向光蛋白介导的，并通过优化生长方向在幼苗形态建成中起着关键作用。然而，向光性影响形态发生的机制需要进一步的研究，特别是对于棉花等多倍体作物。在此，我们发现亚洲棉下胚轴的向光性较弱。raimondii（2个二倍体棉种），LC-MS分析表明G.植物下胚轴脱落酸（阿坝）含量较高，吲哚乙酸（IAA）和赤霉素（GAs）含量较低。ABA 2、AAO 3和GA 2 OX 1在G.比在G.这些变化促进了阿坝的合成和活性GA向非活性GA的转化。较高浓度的阿坝抑制了IAA在下胚轴中的不对称分布，阻断了G.雷蒙地。在下胚轴的阴影侧和光照侧施IAA或GA 3分别增强和抑制了G.植物园在下胚轴的一侧施用IAA，而不是GA，会导致下胚轴在黑暗中弯曲。这些结果表明，IAA的不对称分布促进了G. arboreum的生长受到GA信号的调节，这可能是由于其较高的阿坝浓度抑制了生长素的作用。
Hypocotyl phototropism is mediated by the phototropins and plays a critical role in seedling morphogenesis by optimizing growth orientation. However, the mechanisms by which phototropism influences morphogenesis require additional study, especially for polyploid crops such as cotton. Here, we found that hypocotyl phototropism was weaker inGossypium arboreumthan inG. raimondii(two diploid cotton species), and LC-MS analysis indicated thatG. arboreumhypocotyls had a higher content of abscisic acid (ABA) and a lower content of indole-3-acetic acid (IAA) and bioactive gibberellins (GAs). Consistently, the expression ofABA2,AAO3, andGA2OX1was higher inG. arboreumthan inG. raimondii, and that ofGA3OXwas lower; these changes promoted ABA synthesis and the transformation of active GA to inactive GA. Higher concentrations of ABA inhibited the asymmetric distribution of IAA across the hypocotyl and blocked the phototropic curvature ofG. raimondii. Application of IAA or GA3to the shaded and illuminated sides of the hypocotyl enhanced and inhibited phototropic curvature, respectively, inG. arboreum. The application of IAA, but not GA, to one side of the hypocotyl caused hypocotyl curvature in the dark. These results indicate that the asymmetric distribution of IAA promotes phototropic growth, and the weakened phototropic curvature ofG. arboreummay be attributed to its higher ABA concentrations that inhibit the action of auxin, which is regulated by GA signaling.