Auxin Regulates Cotton Fiber Initiation via GhPIN-Mediated Auxin Transport
Auxin Regulates Cotton Fiber Initiation via GhPIN-Mediated Auxin Transport
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生长素通过 GhPIN 介导的生长素转运调节棉纤维起始
DOI：
10.1093/pcp/pcw203
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发表时间：
2017-02-01
影响因子：
4.9
通讯作者：
Pei, Yan
中科院分区：
文献类型：
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作者：
Zhang, Mi;Zeng, Jian-Yan;Pei, Yan
棉纤维是种子毛状体，使棉花与其他植物相比具有独特性。花期时，IAA（植物中的一种主要生长素）在纤维细胞中积聚以促进细胞起始。然而，这个过程的许多重要方面尚不清楚。在此，研究了纤维细胞分化和细胞起始期间 [-2 至 2 DPA（花后天）] 期间棉花胚珠中生长素依赖性 DR5::GUS（β-葡萄糖醛酸酶）表达所指示的生长素分布模式。珠心和纤维细胞是生长素积累的两个主要部位。珠心中的积累从-1DPA开始，纤维细胞中的积累从0DPA开始。免疫定位分析进一步表明 IAA 在纤维首字母中的积累在花开放之前就开始了。此外，我们证明纤维初始中积累的 IAA 主要来自外排运输，而不是来自原位合成。鉴定了 11 个生长素外排载体 (GhPIN) 基因，并研究了它们在胚珠和纤维发育过程中的表达。转基因棉花中多个 GhPIN 基因的胚珠特异性抑制抑制了纤维的起始和伸长。在 0 DPA 胚珠中，与其他 GhPIN 基因不同，GhPIN3a 显示转录物在外珠被中的额外定位。总的来说，这些结果证明了 GhPIN 介导的生长素转运在纤维特异性生长素积累和纤维起始过程中的重要作用。
Cotton fibers are seed trichomes that make cotton unique compared with other plants. At anthesis, IAA, a major auxin in plants, accumulates in the fiber cell to promote cell initiation. However, many important aspects of this process are not clear. Here, auxin distribution patterns indicated by auxin-dependent DR5::GUS (beta-glucuronidase) expression in cotton ovules were studied during fiber cell differentiation and cell initiation [-2 to 2 DPA (days post-anthesis)]. The nucellus and fiber cell were two major sites where auxin accumulates. The accumulation in the nucellus started from -1 DPA, and that in fiber cells from 0 DPA. Immunolocalization analysis further suggests that the IAA accumulation in fiber initials began before flower opening. Furthermore, we demonstrate that accumulated IAA in fiber initials was mainly from efflux transport and not from in situ synthesis. Eleven auxin efflux carrier (GhPIN) genes were identified, and their expression during ovule and fiber development was investigated. Ovule-specific suppression of multiple GhPIN genes in transgenic cotton inhibited both fiber initiation and elongation. In 0 DPA ovules, GhPIN3a, unlike other GhPIN genes, showed additional localization of the transcript in the outer integument. Collectively, these results demonstrate the important role of GhPIN-mediated auxin transport in fiber-specific auxin accumulation for fiber initiation.