《植物生理学报》 2017, 53(8): 1444-1452

超量表达NtHAK1基因提高烟草干旱胁迫能力

张祎^1,*, 秦利军^1,*, 赵丹¹, 赵德刚^1,2,**

¹贵州大学农业生物工程研究院/生命科学学院, 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, 贵阳550025; ²贵州省农业科学院, 贵阳550006

通信作者：张祎；E-mail: dgzhao@gzu.edu.cn

摘　要：

高亲和钾离子通道蛋白(high-affinity potassium transporter protein, HAK)在植物干旱胁迫过程中起重要调控作用。本研究以超量表达NtHAK1基因烟草(Nicotiana tabacum) T₄代种子为材料, 分析干旱胁迫后种子发芽相关生理指标以及烟草抗性相关指标。结果表明, 干旱处理后, 转基因烟草种子的平均发芽势、发芽率和发芽指数均高于野生型烟草种子。随干旱处理时间的延长, 野生型烟草3 d即出现叶片萎蔫并停止生长, 而转基因烟草到10 d出现叶片萎蔫现象, 野生型烟草叶片相对含水量降幅更大。同时, 干旱胁迫3 d时, 转基因烟草植株体内MDA积累量显著低于野生型(P<0.05)。转基因和野生型烟草植株脯氨酸含量、SOD活性和CAT活性均呈上升趋势, 但转基因烟草植株的涨幅高于野生型, 差异达到显著水平(P<0.05)。干旱胁迫引起转基因烟草植株钾吸收相关基因VAG1和HAK1表达上调。干旱胁迫3 d时, 超量表达NtHAK1基因极显著提高了植株钾含量。综上所述, 超量表达NtHAK1基因增强了烟草在干旱逆境中的耐受力。本研究为后续培育耐旱烟草新种质和进一步研究超量表达NtHAK1烟草对干旱胁迫耐受机制提供参考。

关键词：NtHAK1; 干旱胁迫; 生理指标; 烟草

收稿：2017-04-01   修定：2017-06-26

资助：中国烟草总公司贵州省分公司科技项目专项(2012-01)和国家转基因新品种培育重大专项(2016ZX08010013-002)。

Improvement of drought-stress in NtHAK1-overexpressing Nicotiana tabacum

ZHANG Yi^1,*, QIN Li-Jun^1,*, ZHAO Dan¹, ZHAO De-Gang^1,2,**

¹Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang 550025, China; ²Guizhou Academy of Agricultural Sciences, Guiyang 550006, China

Corresponding author: ZHANG Yi; E-mail: dgzhao@gzu.edu.cn

Abstract:

The high-affinity potassiumion transporter protein (HAK) plays an important role in improving the drought-stress in plants. In this study, we investigated the effect of drought-stress on germination performance in tobacco seeds and some physiological characteristics of HAK1-overexpressing tobaccos. The result showed that the germination potential, germination rate and germination index in transgentic plants were higher than those in wild-type tobaccos. At 3 days after drought-stress, leaves of the wild-type tobaccos began to wilter and stop growing, when the transgenic tobaccos appeared signs of wilting at 10 days. The decreasing amplitude of leaf relative water content in wild-type plants were higher than that in transgenic tobaccos. At 3 days after drought treatment, the content of MDA in transgenic plants was significantly higher than wild-type ones (P<0.05). The content of proline, and the activities of SOD, CAT in both transgenic and wild-type plants were rising up, while the transgenic plants increasing significantly higher than that in the wild type (P<0.05). Meanwhile, the expression of potassium ion absorption-related genes (VAG1 and HAK1) was up-regulated significantly after drought treatment. In addition, the potassium content of overexpression plants increased at 3 days after drought treatment. In conclusion, overexpression of NtHAK1 gene could enhanced the tolerance of drought stress in tobaccos. This study provides the plant materials for breeding the drought-stress tobaccos and further studying the mechanism of HAK1-mediated drought-stress in transgenic plants.

Key words: NtHAK1; drought-stress; physiological characteristics; tobacco