《植物生理学报》 2018, 54(4): 651-659

超表达小麦硝态氮转运蛋白基因TaNRT2.1对拟南芥生长及氮吸收的影响

李文虎, 田汇^*, 高亚军

农业部西北植物营养与农业环境重点实验室/西北农林科技大学资源环境学院, 陕西杨凌712100

通信作者：田；E-mail: tianh@nwsuaf.edu.cn

摘　要：

为了阐明小麦硝态氮转运蛋白(nitrate transporters, NRT) TaNRT2.1及辅助蛋白TaNAR2.1的硝态氮转运功能, 本研究构建了TaNRT2.1单基因(单超)与TaNRT2.1+TaNAR2.1双基因超表达载体(双超), 通过农杆菌介导法转化野生型拟南芥, 利用潮霉素筛选与PCR鉴定分别获得了3个单超与2个双超的转基因拟南芥纯合株系。通过研究转基因拟南芥的硝态氮吸收动力学及氮含量发现: 在硝态氮浓度>1 mmol·L^-1时, 仅双超能够显著提高拟南芥的硝态氮吸收速率; 硝态氮浓度<1 mmol·L^-1时, 不论单超还是双超均不能提高拟南芥的硝态氮吸收速率。低氮(0.1 mmol·L^-1 NO₃^-)条件下, 2种转基因拟南芥的生长状况和氮吸收与野生型相比均无显著差异; 而在高氮(10 mmol·L^-1 NO₃^-)条件下, 单超提高了拟南芥的角果重和植株生物量, 双超则显著提高了拟南芥的生物量、根系生长和总吸氮量。这些结果表明, TaNRT2.1转运蛋白需与辅助蛋白TaNAR2.1联合才能调控拟南芥对硝态氮的转运。

关键词：超表达; TaNRT2.1; TaNAR2.1; 拟南芥; 氮效率; 小麦

收稿：2017-11-08   修定：2018-03-14

资助：中央高校基本科研业务费专项资金(2452015048和2452-015346)。

Influence of over-expressing the wheat nitrate transporter genes TaNRT2.1 on affected the growth and nitrogen uptake of Arabidopsis thaliana

LI Wen-Hu, TIAN Hui^*, GAO Ya-Jun

Key Laboratory of Plant Nutrition and Agri-Environment in Northwest China, Ministry of Agriculture, College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China

Corresponding author: TIAN Hui; E-mail: tianh@nwsuaf.edu.cn

Abstract:

The function of the wheat nitrate transporter (NRT) gene TaNRT2.1 in nitrate uptake was studied via over-expressing this gene in Arabidopsis thaliana. To investigate the cooperation of TaNRT2.1 with the protein TaNAR2.1, a vector included these two genes promoted by 35s promoter was also constructed and transformed into Arabidopsis. Homozygotes of the transformed Arabidopsis plants were screened, and the nitrate uptake dynamics and nitrogen (N) content of the homozygotes were measured. The results indicated that only over-expressing both of TaNRT2.1 and TaNAR2.1 could significantly increase the nitrate uptake rates compared to the wild-type Arabidopsis plants in the high nitrate concentration (> 1 mmol·L^-1). In the low nitrate condition (0.1 mmol·L^-1 NO₃^-), the growth and total N uptake of the transgenic Arabidopsis plants were not different from the wild-type plants. In the high nitrate condition (10 mmol·L^-1 NO₃^-), over-expressing TaNRT2.1+TaNAR2.1 significantly increased the biomass, root growth and total N uptake in Arabidopsis plants; and over-expressing TaNRT2.1 singly only increased the silique dry weight and shoot biomass. The present study suggested that TaNRT2.1 needed to cooperate with TaNAR2.1 in mediating plant nitrate uptake.

Key words: over-expression; TaNRT2.1; TaNAR2.1; Arabidopsis thaliana; nitrogen uptake efficiency; wheat