异位表达赤霉素降解酶基因促进木本植物小桐子成花转变

Ectopic Expression of Gibberellin-degrading Gene Promoted Floral Transition in Woody Plant Jatropha curcas

小桐子(Jatropha curcas L.)是一种多年生木本油料作物,其营养生长过于旺盛是其种子产量低的原因之一。赤霉素在大多数多年生木本植物中抑制成花转变。为了降低小桐子内源赤霉素含量、促进植株的生殖生长,本研究采用拟南芥花特异性表达的AtAP1(Arabidopsis thaliana APETALA1)启动子驱动小桐子赤霉素降解酶基因JcGA2ox6在小桐子中表达。结果显示:转基因小桐子的叶片颜色变深,叶面积变小,单株总花序数目显著增多,花序变小而紧凑,且雌花和雄花变小,雌雄花数目均减少,单个花序中的雌花比例降低。本研究结果表明通过特异性表达小桐子JcGA2ox6能促进其由营养生长向生殖生长的转变。

Physic nut(Jatropha curcas L.)is a perennial woody oil plant.Its vegetative growth is excessive,which is one of the factors restricting its seed yield.Gibberellin(GA)inhibits floral formation in most perennial woody plants.Shoot reproductive growth could be promoted by reducing endogenous gibberellin content.Therefore,in this study,a Jatropha gibberellin 2-oxidase 6(JcGA2ox6)which catalyzes GA degradation was driven by a flower-specific promoter,Arabidopsis thaliana APETALA1(AtAP1)promoter,in Jatropha.The results showed that the leaves became darker and smaller,the numbers of inflorescence per plant were significantly increased,the inflorescences became smaller and compact,both female and male flowers decreased in size and number,and the ratios of female to male flowers decreased in AtAP1:JcGA2ox6 transgenic Jatropha.Our results showed that flower-specific expressions of JcGA2ox6 could promote the transition from vegetative to reproductive growth in Jatropha.