高糖甜菜BvNHX1基因的克隆及表达特性分析

Cloning and Expression Analysis of BvNHX1 from Beta vulgaris with High Sucrose

本研究以高糖甜菜品种‘BS02’为材料,采用同源克隆技术分离其液泡膜Na+/H+逆向转运蛋白基因,命名为BvNHX1。该基因包含有1 659 bp的开放阅读框,编码552个氨基酸,蛋白分子量为61.31 kD,理论等电点为6.31。预测该基因编码的蛋白具有12个跨膜结构域,同时具有Nhap、NaHExchanger和bcpa1超家族的保守结构域,而且与盐角草、犁苞滨藜、盐地碱蓬等多种藜科植物NHXs聚为一类,属于液泡膜NHX家族中的ClassⅠ成员。实时荧光定量PCR结果显示:在400 mmol/L NaCl、200 mmol/L KCl和15 mmol/L ABA处理下,该基因表达量分别在叶和根中达到峰值,且叶中的表达量均显著高于根中,表明该基因在响应NaCl、KCl和ABA时,可能在叶中发挥的作用远大于根中。本研究结果将为甜菜耐盐分子机理的研究奠定基础,同时为高糖甜菜耐盐性遗传改良提供坚实可靠的依据。

In the present study, the vac uolar Na+/H+exchanger gene was isolated by homologous cloning technology from the high-sucrose Beta vulgaris(’BS02’), referred to as BvNHX1, which contained an ORF of 1 659 bp,encoded 552 amino acids, the protein molecular weight was 61.31 kD, and the theoretical isoelectric point was6.31. The protein encoded by BvNHX1 gene had 12 transmembrane domains and the conserved domains of Nhap,NaHExchanger and bcpa1 superfamily, and grouped with various NHXs of Chenopodiaceae plants, such as Salicornia europaea, Atriplex dimorphostegia, Suaeda salsa, and belonged to Class Ⅰ in the vacuolar Na+/H+exchanger family. Quantitative real-time PCR results showed that under 400 mmol/L NaCl, 200 mmol/L KCl and15 mmol/L ABA, the expression of BvNHX1 reached the peaks in leaves and roots, respectively, and the expression of BvNHX1 in leaves was significantly higher than that in roots, indicating that the expression of BvNHX1 was induced by NaCl, KCl and ABA, and it may play a greater role in leaves than roots in response to abiotic stresses.This study will lay a foundation for the study of the salt tolerance molecular mechanism in sugar beet, and provide a solid and reliable basis for the genetic improvement of salt tolerance in high sugar beet.