State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang 455000, China; College of Life Science, Yan'an University, Yan'an, 716000, China; College of Agronomy, Northwest A&F University, Yangling 712100, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang 455000, China; College of Agronomy, Northwest A&F University, Yangling 712100, China.
Plant Sci. 2020 Apr;293:110395. doi: 10.1016/j.plantsci.2019.110395. Epub 2019 Dec 31.
Pectate lyases (PELs) play important roles in plant growth and development, mainly by degrading the pectin in primary cell walls. However, the role of PELs in cotton fiber elongation, which also involves changes in cellular structure and components, is poorly understood. Therefore, we aimed to isolate and characterize GhPEL76, as we suspected it to contribute to the regulation of fiber elongation. Expression analysis (qRT-PCR) revealed that GhPEL76 is predominately expressed in cotton fiber, with significantly different expression levels in long- and short-fiber cultivars, and that GhPEL76 expression is responsive to gibberellic acid and indoleacetic acid treatment. Furthermore, GhPEL76 promoter-driven β-glucuronidase activity was detected in the roots, hypocotyls, and leaves of transgenic Arabidopsis plants, and the overexpression of GhPEL76 in transgenic Arabidopsis promoted the elongation of several organs, including petioles, hypocotyls, primary roots, and trichomes. Additionally, the virus-induced silencing of GhPEL76 in cotton reduced fiber length, and both yeast one-hybrid and transient dual-luciferase assays suggested that GhbHLH13, a bHLH transcription factor that is up-regulated during fiber elongation, activates GhPEL76 expression by binding to the G-box of the GhPEL76 promoter region. Therefore, these results suggest GhPEL76 positively regulates fiber elongation and provide a basis for future studies of cotton fiber development.
果胶裂解酶（PELs）在植物生长和发育中起着重要作用，主要通过降解初生细胞壁中的果胶来实现。然而，PELs 在棉花纤维伸长中的作用，这也涉及到细胞结构和成分的变化，目前还知之甚少。因此，我们旨在分离和表征 GhPEL76，因为我们怀疑它参与了纤维伸长的调控。表达分析（qRT-PCR）显示，GhPEL76 在棉花纤维中表达为主，在长纤维和短纤维品种中表达水平有显著差异，并且 GhPEL76 的表达对赤霉素和吲哚乙酸处理有反应。此外，在转基因拟南芥植物的根、下胚轴和叶片中检测到 GhPEL76 启动子驱动的β-葡萄糖醛酸酶活性，过表达 GhPEL76 促进了几个器官的伸长，包括叶柄、下胚轴、初生根和毛状体。此外，棉花中 GhPEL76 的病毒诱导沉默减少了纤维长度，酵母单杂交和瞬时双荧光素酶测定表明，GhbHLH13 是一个在纤维伸长过程中上调的 bHLH 转录因子，通过结合 GhPEL76 启动子区域的 G 盒激活 GhPEL76 的表达。因此，这些结果表明 GhPEL76 正向调控纤维伸长，并为未来的棉花纤维发育研究提供了基础。
