廖嘉明 包钰韬 陈媛 张登 李华强 欧阳昆唏 陈晓阳

摘 要： 为探究NcEXPA8基因的分子功能，该文以在黄梁木形成层区域中高表达的扩展蛋白基因NcEXPA8为研究对象，研究其在黄梁木种子萌发过程中的表达及其过表达对拟南芥种子萌发的影响。该文以黄梁木和拟南芥野生型（WT）（Col-0）种子以及转NcEXPA8基因的拟南芥T3代纯合体种子为实验材料，利用实时荧光定量RT-qPCR分析NcEXPA8基因在黄梁木种子萌发不同阶段的表达量，并分析NcEXPA8基因和拟南芥种子萌发内源相关基因在拟南芥WT和转基因不同株系萌发种子中的表达量，且对拟南芥WT种子和转基因T3代纯合体种子在不同处理和不同时间的萌发率进行比较。结果表明：NcEXPA8基因在黄梁木种子萌发不同阶段的表达量存在差异，在种壳破裂时表达量最高，随后降低。与拟南芥WT相比，过表达NcEXPA8基因不仅显著提高了种子的萌发速度，而且提高了对赤霉素的敏感性，降低了对脱落酸的敏感性，但未影响拟南芥内源相关结构基因的表达。该研究初步分析了黄梁木NcEXPA8基因在种子萌发中的功能，但其最终确定还需在黄梁木中进行验证。

关键词： 黄梁木， NcEXPA8基因， 种子萌发， 拟南芥

中图分类号： S722

文献标识码： A

文章编号： 1000-3142（2021）04-0654-08

Abstract： In order to explore the molecular function of NcEXPA8 gene， which is highly expressed in the cambium region of N. cadamba， NcEXPA8 gene expression during seed germination of N. cadamba and the effect of its overexpression on seed germination of Arabidopsis thaliana were studied. The seeds of Neolamarckia cadamba， Arabidopsis thaliana wild type （WT， Col-0） and T3 homozygote of A. thaliana overexpressing NcEXPA8 gene were selected as experimental materials. Quantitative real-time polymerase chain reaction （RT-qPCR） was used to analyze the expression of NcEXPA8 gene in different stages during seed germination of Neolamarckia cadamba， and also its expression level and that of endogenous related genes in the germinating seeds of A. thaliana WT and T3 transgenic homozygotes. Furthermore， the germination rates of WT and T3 homozygous seeds of Arabidopsis thaliana were compared at different treatments and different time. The results were as follows： The expression level of NcEXPA8 gene was different among different stages during seed germination of Neolamarckia cadamba， and its expression level was the highest when the seed coat was broken， and then decreased. Compared to wild type of Arabidopsis thaliana， the overexpression of NcEXPA8 gene not only significantly increased seed germination speed， but also increased the sensitivity to GA and reduced the sensitivity to ABA， but did not affect the expression of endogenous related structural genes in A. thaliana. This study preliminarily analyzes the function of NcEXPA8 gene in seed germination， but its final determination still need to be verified in Neolamarckia cadamba.

Key words： Neolamarckia cadamba， NcEXPA8 gene， seed germination， Arabidopsis thaliana

植物擴展蛋白（expansin， 简称EXP）首次在黄瓜下胚轴中被发现，是一类负责酸性诱导细胞壁伸展的细胞壁蛋白，但不具有细胞壁水解活性（Mcqueen-Mason et al.， 1992）。对植物而言，细胞壁是一种极其重要的结构，提供植物所需的机械支持，同时为植物组织器官生长发育提供可塑性;植物的生长发育需要改变细胞的大小和形状，这就需要对细胞壁的可塑性进行调节（Marowa et al.， 2016）。……