拟南芥NCED3基因在水稻中的过量表达可以提高水稻的干旱胁迫耐受性

Overexpression of AtNCED3 Gene in Rice Exhibits Improved Drought Tolerance in Transgenic Plants

9-顺-环氧类胡萝卜素双加氧酶(NCED)是高等植物脱落酸(ABA)生物合成途径中的关键酶,其催化的裂解反应直接生成ABA的前体物质.本文应用拟南芥rd29A诱导型启动子和35S组成型启动子成功地将At-NCED3基因在水稻中过量表达,通过耐旱性筛选实验证明转基因水稻对干旱胁迫的耐受性有了显著提高,并且该优良性状在T2代中得到稳定遗传.进一步的分析表明,过量表达AtNCED3可以促进转基因水稻种子的休眠;在含rd29A诱导型启动子的转基因水稻中检测到ABA下游基因OsBZ8的表达;推测AtNCED3在水稻中的过量表达可能会提高水稻中内源ABA的水平,从而提高植株的耐旱性.

NCED is the key enzyme of ABA biosynthesis in higher plants. It cleaves 9-cis xanthophylls to xanthoxin, a precursor of ABA. In this study, AtNCED3 gene with the rd29A promotor or 35S promotor was introduced into a rice plant. The results indicated that the overexpression of AtNCED3 in rice improved the drought tolerance of T1 and T2 transgenic rice seedlings and enhanced the dormancy of the seeds. The ABA downstream gene OsBZ8 expressed in the transgenic rice of AtNCED3 with a rd29A promoter tinder the drought stress. These suggested that overexpression of AtNCED3 might increase the levd of endogenous ABA.