Lee Jinsuk J, Woodward Andrew W, Chen Z Jeffrey
Sections of Molecular Cell and Developmental Biology.
Ann Bot. 2007 Dec;100(7):1391-401. doi: 10.1093/aob/mcm232. Epub 2007 Sep 27.
Cotton is the dominant source of natural textile fibre and a significant oil crop. Cotton fibres, produced by certain species in the genus Gossypium, are seed trichomes derived from individual cells of the epidermal layer of the seed coat. Cotton fibre development is delineated into four distinct and overlapping developmental stages: fibre initiation, elongation, secondary wall biosynthesis and maturation.
Recent advances in gene expression studies are beginning to provide new insights into a better understanding of early events in cotton fibre development. Fibre cell development is a complex process involving many pathways, including various signal transduction and transcriptional regulation components. Several analyses using expressed sequence tags and microarray have identified transcripts that preferentially accumulate during fibre development. These studies, as well as complementation and overexpression experiments using cotton genes in arabidopsis and tobacco, indicate some similar molecular events between trichome development from the leaf epidermis and fibre development from the ovule epidermis. Specifically, MYB transcription factors regulate leaf trichome development in arabidopsis and may regulate seed trichome development in cotton. In addition, transcript profiling and ovule culture experiments both indicate that several phytohormones and other signalling pathways mediate cotton fibre development. Auxin and gibberellins promote early stages of fibre initiation; ethylene- and brassinosteroid-related genes are up-regulated during the fibre elongation phase; and genes associated with calmodulin and calmodulin-binding proteins are up-regulated in fibre initials. Additional genomic data, mutant and functional analyses, and genome mapping studies promise to reveal the critical factors mediating cotton fibre cell development.
棉花是天然纺织纤维的主要来源,也是一种重要的油料作物。棉纤维由棉属的某些物种产生,是源自种皮表皮层单个细胞的种子毛状体。棉纤维发育可分为四个不同但相互重叠的发育阶段:纤维起始、伸长、次生壁生物合成和成熟。
基因表达研究的最新进展开始为更好地理解棉纤维发育的早期事件提供新的见解。纤维细胞发育是一个复杂的过程,涉及许多途径,包括各种信号转导和转录调控成分。使用表达序列标签和微阵列的多项分析已经鉴定出在纤维发育过程中优先积累的转录本。这些研究以及在拟南芥和烟草中使用棉花基因的互补和过表达实验表明,叶表皮的毛状体发育和胚珠表皮的纤维发育之间存在一些相似的分子事件。具体而言,MYB转录因子调节拟南芥中叶毛状体的发育,也可能调节棉花中种子毛状体的发育。此外,转录谱分析和胚珠培养实验均表明,几种植物激素和其他信号通路介导棉纤维发育。生长素和赤霉素促进纤维起始的早期阶段;乙烯和油菜素内酯相关基因在纤维伸长阶段上调;与钙调蛋白和钙调蛋白结合蛋白相关的基因在纤维起始细胞中上调。更多的基因组数据、突变体和功能分析以及基因组图谱研究有望揭示介导棉纤维细胞发育的关键因素。