《植物生理学报》 2014, 50(12): 1889-1898

转玉米ZmSDD1基因烟草降低气孔密度提高抗旱性

刘延波^1,2, 项阳^1,3, 秦利军^1,2, 赵德刚^1,2,3,*

贵州大学¹农业生物工程研究院, 山地植物资源保护与种质创新省部共建教育部重点实验室, ²绿色农药与农业生物工程国家重点实验室培育基地, ³生命科学学院基因工程实验室, 贵阳550025

通信作者：赵德刚；E-mail: dgzhao@gzu.edu.cn；Tel: 0851-3863615

摘　要：

为了培育抗旱的烟草新品种并研究玉米SDD1基因(ZmSDD1)的功能, 从玉米中同源克隆到ZmSDD1, 构建了含有玉米Ubiquitin启动子驱动的ZmSDD1基因的植物表达载体pGM626-Ubi-ZmSDD1-ABt, 并利用叶盘转化法遗传转化烟草, 筛选获得转基因植株。经反复干旱处理发现, 转Ubiquitin::ZmSDD1基因烟草存活率比野生型高80%, 转基因植株中PRO含量以及POD和SOD活性均显著高于野生型烟草植株, MDA含量则低于野生型植株。转ZmSDD1基因烟草植株和野生型植株的气孔导度、细胞间二氧化碳浓度和蒸腾速率在干旱后都有所下降, 但转基因植株的净光合速率极显著高于野生型。转Ubiquitin::ZmSDD1烟草植株叶片表面气孔数较野生型相比减少50%。Real-time PCR结果显示转基因烟草和野生型相比负调控气孔密度的ZmSDD1基因和MAPK3基因表达量均极显著上调, 正调控气孔密度的FAMA基因极显著下调。结果说明, 转ZmSDD1植株比野生型植株抗旱的原因是由于ZmSDD1基因负调控了气孔发育相关基因的表达从而使气孔密度降低, 减少蒸腾作用, 减少水分散失从而提高抗旱性。

关键词：烟草; 气孔密度; ZmSDD1; 抗旱

收稿：2014-10-13   修定：2014-11-20

资助：国家转基因生物新品种培育科技重大专项子课题(2014ZX0801008B-002)、国家转基因生物新品种培育科技重大专项子课题(2014ZX08010-003)和贵州省科技厅转基因专项(黔科合2004NZ004)。

Improvement of Drought Tolerance in Transgenic Tobacco Expressed Maize ZmSDD1 by Reducing Stomatal Density

LIU Yan-Bo^1,2, XIANG Yang^1,3, QIN Li-Jun^1,2, ZHAO De-Gang^1,2,3,*

¹Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering, ²State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, ³Genetic Engineering Laboratory in College of Life Sciences, Guizhou University, Guiyang 550025, China

Corresponding author: ZHAO De-Gang; E-mail: dgzhao@gzu.edu.cn; Tel: 0851-3863615

Abstract:

In this study, a ZmSDD1 gene derived from Zea mays was cloned by homology-based cloning method. The plant expression vector, named by pGM626-Ubi-ZmSDD1-ABt, contained Z. mays Ubiquitin promoter-driven ZmSDD1 was constructed for studying the function of the gene. The transformation method mediated by Agrobacterium was executed to genetically transform the tobacco leaf disks. In addition to, the results from the repeated drought experiments indicated that the survival rate was about 80% higher in transgenic tobacco plants than wild-type plants. By the enzyme activity of SOD and POD and the content of PRO and MDA determined after drought, we concluded that the transgenic plants could bear the drought stress by increasing SOD and POD enzyme activity and PRO content. The stomatal conductance, intercellular CO2 concentration and transpiration rate were decreased in transgenic and wild-type plants, but net photosynthetic rate was significantly higher in transgenic plants than wild-type ones. Results from microscopic observation found that the stomatal number in transgenic tobacco plants decreased 50% compared with the wild-type ones. Meanwhile, the relative expression of the genes in stoma development-related were analyzed and the results showed that the relative expression of two genes, MAPK3 and ZmSDD1 which was negative correlation with stomatal development, were up-regulated obviously, while the FAMA gene of positive correlation with the development reported was significantly down-regulated simultaneously. To sum up, the ZmSDD1 transgenic tobacco plants could resist drought stress by decreasing the stomatal density of leaf surface and transpiration.

Key words: tobacco; stomatal density; ZmSDD1; drought tolerance