NMT历史上的今天丨New Phytol：GhCaM7调节活性氧促进棉纤维伸长

NMT是基因功能的活体检测技术，已被103位诺贝尔奖得主所在单位，及北大、清华、中科院使用。

NMT历史上的今天

2013年12月09日，华中农业大学张献龙、涂礼莉、唐文鑫用NMT在New Phytologist上发表了标题为The calcium sensor GhCaM7 promotes cotton fiber elongation by modulating reactive oxygen species (ROS) production的研究成果。

期刊：New Phytologist

主题：GhCaM7调节活性氧（ROS）促进棉纤维伸长

标题：The calcium sensor GhCaM7 promotes cotton fiber elongation by modulating reactive oxygen species (ROS) production

影响因子：6.736

检测指标：Ca2+流速

作者：华中农业大学张献龙、涂礼莉、唐文鑫

英文摘要

Fiber elongation is the key determinant of fiber quality and output in cotton (Gossypium hirsutum). Although expression profiling and functional genomics provide some data, the mechanism of fiber development is still not well understood.

Here, a gene encoding a calcium sensor, GhCaM7, was isolated based on its high expres-sion level relative to other GhCaMs in fiber cells at the fast elongation stage. The level of expression of GhCaM7 in the wild-type and the fuzzless/lintless mutant correspond to the presence and absence, respectively, of fiber initials.

Overexpressing GhCaM7 promotes early fiber elongation, whereas GhCaM7 suppression by RNAi delays fiber initiation and inhibits fiber elongation. Reactive oxygen species (ROS) play important roles in early fiber development. ROS induced by exogenous hydrogen perox-ide (H2O2) and Ca2+ starvation promotes early fiber elongation. GhCaM7 overexpression fiber cells show increased ROS concentrations compared with the wild-type, while GhCaM7 RNAi fiber cells have reduced concentrations. Furthermore, we show that H2O2 enhances Ca2+ influx into the fiber and feedback-regulates the expression of GhCaM7.

We conclude that GhCaM7, Ca2+ and ROS are three important regulators involved in early fiber elongation. GhCaM7 might modulate ROS production and act as a molecular link between Ca2+ and ROS signal pathways in early fiber development.

中文摘要（谷歌机翻）

纤维伸长率是决定棉花（陆地棉）纤维质量和产量的关键因素。尽管表达谱和功能基因组学提供了一些数据，但是纤维发育的机制仍未得到很好的理解。

在此，基于钙离子传感器GhCaM7的表达水平相对于其在纤维细胞中处于快速延伸阶段的其他GhCaMs高表达水平而被分离出来。GhCaM7在野生型和无绒毛/无绒毛突变体中的表达水平分别对应于纤维首字母的存在与否。

过表达的GhCaM7促进了早期纤维的伸长，而RNAi对GhCaM7的抑制则延迟了纤维的启动并抑制了纤维的伸长。活性氧（ROS）在纤维早期发育中起重要作用。外源过氧化氢（H2O2）和Ca2+饥饿诱导的ROS促进了早期纤维的伸长。与野生型相比，GhCaM7过表达纤维细胞的ROS浓度升高，而GhCaM7 RNAi纤维细胞的ROS浓度降低。此外，我们表明，H2O2增强了Ca2+的入流，并反馈调节GhCaM7的表达。

我们得出结论，GhCaM7，Ca2+和ROS是参与早期纤维伸长的三个重要调控因子。GhCaM7可能调节ROS的产生，并在早期纤维发育中充当Ca2+和ROS信号通路之间的分子链接。​

(b) Ca2+ flux during fiber development was measured by a noninvasive scanning ion-selective electrode technique. During fiber elongation, there was an increasing Ca2+influx from the extracellular to the intracellular environment and the flux rate peaked during plasmodesmatal closure from 10 to 15 d postanthesis (DPA). The rate of Ca2+influx subsequently decreased during the secondary cell wall synthesis. The inset (lower left) is a schematic diagram for the measurement of Ca2+ flux in testing buffer by noninvasive scanning ion-selective electrode. Error bars, SD of nine samples.