水稻胚乳过表达VIT1/VIT2对Fe和Cd积累的影响

Effect of VIT1/VIT2 overexpression on Fe and Cd accumulation in rice endosperm

摘要:

水稻籽粒铁（Fe）缺乏和镉（Cd）含量超标是农业生产亟待解决的重要问题。以往研究表明，OsVIT1和OsVIT2是液泡铁转运蛋白，本研究选取野生型ZH11为背景材料，使用胚乳特异性表达启动子Glb-1构建了胚乳过表达OsVIT1和OsVIT2材料。RT-qPCR分析表明，OsVIT1在转化植株的胚乳和叶片过量表达，OsVIT2在转化植株的胚乳过量表达。通过田间试验，研究胚乳过表达OsVIT1和OsVIT2对水稻不同部位Fe和Cd积累的影响。结果表明，胚乳过表达OsVIT1显著降低籽粒中的Fe浓度约50%，显著增加秸秆的锌（Zn）、铜（Cu）浓度和籽粒中的Cu浓度，胚乳过表达OsVIT2显著降低籽粒中的Fe、Cd浓度约50%，显著增加秸秆的Fe浓度45%–120%。胚乳过表达OsVIT1和OsVIT2不影响水稻的农艺性状。总之，胚乳过表达OsVIT1和OsVIT2降低了水稻籽粒的Fe积累，未达到预期效果，胚乳过表达OsVIT2还降低籽粒的Cd积累，增加秸秆Fe积累，为水稻铁生物强化和降镉提供了借鉴。

Abstract:

Iron (Fe) deficiency and excess cadmium (Cd) in rice grain are important problems to be solved in agricultural production. Previous studies have shown that OsVIT1 and OsVIT2 are vacuolar iron transporters. In this study, wild-type ZH11 was selected as the background material and OsVIT1 and OsVIT2 were overexpressed in endosperm by using endosperm specific promoter Glb-1. Field experiments were conducted to study the effect of OsVIT1 and OsVIT2 overexpression on Fe and Cd accumulation in different parts of rice. The results showed that OsVIT1 overexpression in endosperm significantly reduced Fe content in grain by about 50%, while significantly increased zinc (Zn) and copper (Cu) contents in straw and Cu content in grain. OsVIT2 overexpression in endosperm significantly decreased Fe and Cd contents in grain by about 50%, and significantly increased Fe content in straw by 45%-120%. Overexpression of OsVIT1 and OsVIT2 in endosperm did not affect the agronomic traits of rice. In conclusion, OsVIT1 and OsVIT2 overexpression in endosperm reduced Fe accumulation in rice grain, which did not achieve the expected effect. OsVIT2 overexpression in endosperm also decreased Cd accumulation in grain and increased Fe accumulation in straw, which provided reference for iron biofortification and cadmium reduction in rice.