把盐碱地变成良田沃土，是人类自古至今的梦想，如今这个梦想离现实又近了一大步。近日，华东师范大学夏涛教授的课题组，通过基因改组技术创造了一种新的“钠氢逆向转运蛋白”，转入并表达这种新基因的植物，能够在高盐环境下正常生长，这也就意味着这种转基因植物有望成为盐碱地的 “死敌”。
夏涛教授告诉记者，目前全世界土地的1/4到1/3为盐渍化土壤，大约20%的耕种土地和接近一半的灌溉土地都不同程度受到了盐渍化危害。植物通过根吸收水分和养料，也会把盐碱成分运输到整个植物体。如果吸收到体内的盐碱成分浓度过高，植物就会死去，这也是在盐碱地上植物不容易生长的原因。如何培育能够在盐碱地上正常生长的植物特别是培育高耐盐性的转基因工程植物，是进行盐碱地改良的根本出路，也是目前学术界的研究重点。
夏涛教授课题组决定以酵母突变体为高通量的筛选体系，通过基因改组技术强化钠氢逆向转运蛋白的搬运能力，经过一系列的实验，取得了成功。数据显示，这种新创造的钠氢逆向转运蛋白转运盐分的能力比野生的钠氢逆向转运蛋白提高了约1倍。现在，他们还将该基因植入了拟南芥中，结果发现拟南芥在盐碱环境中的生存能力大大提高。他的最新研究成果刚刚在国际著名学术期刊《生物化学杂志》在线发表，目前还申请了中国国家发明专利和国际PCT专利。
目前，夏涛课题组正在改良这种基因，继续提升它的活力，同时开展改良基因的工程化育种。该项成果具有广阔的应用前景。(生物谷Bioon.com)
生物谷推荐原文出处：
JBC doi: 10.1074/jbc.M109.073783
A novel plant vacuolar Na+/H+ antiporter gene evolved by DNA shuffling confers improved salt tolerance in yeast
Kai Xu1, Hui Zhang1, Eduardo Blumwald2 and Tao Xia1,*
Plant vacuolar Na+/H+ antiporters play important roles in maintaining cellular ion homeostasis and mediating the transport of Na+ out of the cytosol and into the vacuole. Vacuolar antiporters have been shown to play significant roles in salt tolerance, however the relatively low Vmax of the Na+/H+ exchange of the Na+/H+ antiporters identified could limit its application in the molecular breeding of salt tolerant crops. In this study, we applied DNA shuffling methodology to generate and recombine the mutations of Arabidopsis thaliana vacuolar Na+/H+ antiporter gene AtNHX1. Screening using a large scale yeast complementation system identified AtNHXS1, a novel Na+/H+ antiporter. Expression of AtNHXS1 in yeast showed that the antiporter localized to the vacuolar membrane and that its expression improved the tolerance of yeast to NaCl, KCl, LiCl and hygromycin B. Measurements of the ion transport activity across the intact yeast vacuole demonstrated that the AtNHXS1 protein showed higher Na+/H+ exchange activity and a slightly improved K+/H+ exchange activity.
