高营　林云　袁星星　薛晨晨　陈新　朱月林

摘要： GASA（Gibberellic acid-stimulated in Arabidopsis）蛋白是一类受赤霉素调控的小分子蛋白质，参与植物生长发育的多条途径。本研究在蚕豆（Vicia faba）中同源克隆了VfGASA1基因，该基因的开放阅读框全长为363 bp，编码1个包含120个氨基酸残基的蛋白质，VfGASA1在蚕豆叶片和嫩荚中高表达，亚细胞定位结果显示，VfGASA1是一个定位于质外体的分泌蛋白。异源过表达VfGASA1导致转基因拟南芥开花延迟、莲座叶数量增多，外施赤霉素能够恢复这一现象。实时荧光定量结果显示，转基因拟南芥植株中FT基因显著下调，而DELLA基因中的GAI基因显著上调，说明VfGASA1可能是通过间接抑制DELLA蛋白的表达从而调控植物开花。本研究结果为蚕豆的开花调控育种提供了理论依据。

关键词： 蚕豆;VfGASA1;拟南芥;开花时间;赤霉素

中图分类号： S643.6 文献标识码： A 文章编号： 1000-4440（2021）01-0044-09

Heterologous overexpression of Vicia faba VfGASA1 gene delays flowering in transgenic Arabidopsis

GAO Ying1， 2， LIN Yun2， YUAN Xing-xing2， XUE Chen-chen2， CHEN Xin2， ZHU Yue-lin1

（1.College of Horticulture， Nanjing Agricultural University， Nanjing 210095， China;2.Institute of Industrial Crops， Jiangsu Academy of Agricultural Sciences， Nanjing 210014， China）

Abstract： Gibberellic acid-stimulated in Arabidopsis （GASA） protein is a kind of protein with small molecular weight regulated by gibberellin and participates in various pathways of plant growth and development. In this study， the GASA gene VfGASA1 in faba bean （Vicia faba） was got by homologous cloning. The open reading frame（ORF） of VfGASA1 was 363 bp in length and encoded a protein containing 120 amino acid residues. VfGASA1 was highly expressed in the leaves and capsules of faba beans， and subcellular localization showed that VfGASA1 was a secretory protein located in the apoplast. Heterologous overexpression of VfGASA1 in Arabidopsis could delay flowering and increase the number of rosette leaves， while the phenomenon could be recovered by the application of exogenous gibberellin. Results of real-time PCR （RT-PCR） showed that the expressional level of ‘florigen gene （FT） was significantly down-regulated in transgenic Arabidopsis while GAI （one of DELLA genes） was significantly up-regulated. Therefore， VfGASA1 might regulate the flowering of plants by indirect inhibiting the expression of DELLA genes. This study provides theoretic basis for breeding programs targeted on the flowering control of faba bean.

Key words： Vicia faba;VfGASA1;Arabidopsis;flowering time;gibberellin

開花是指被子植物由营养生长向生殖生长的转变，是植物生命史的重要相变，也是农作物的重要农艺性状之一;开花时间受到不同信号的影响，在拟南芥中有光周期、自主途径、春化途径及赤霉素（GA）信号途径等[1-4]。一些关键的调控因子负责整合这些信号途径，包括FT、SOC1以及LFY的表达[5-7]，这些调控因子激活LFY、AP1和FUL在花序分生组织侧部的表达，诱导花原基的产生[8]。其中，FT是开花调控的整合因子和决定基因，各信号途径最终通过影响其表达水平而诱导开花。FT基因的表达量受到CO蛋白的正向调控[9]，CO蛋白在光照条件下积累，在黑暗条件下降解，引起FT的节律表达和蛋白质积累，从而影响开花[10]。……