摘要：中国科学院寒区旱区环境与工程研究所植物生理生态与生物工程实验室陈国雄课题组研究人员联合日本、以色列、瑞士等国科学家，在综合性科技期刊PNAS上发表了题为“An ATP-binding cassette subfamily G full transporter is essential for the retention of leaf water in both wild barley and rice”的文章。
研究以野生大麦和水稻为实验材料，克隆了与植物抗旱密切相关的角质层基因Eibi1，发现该基因与叶片角质层保水功能密切相关。该基因编码ABCG全转运子，把角质成分从细胞内运转到叶片表面形成功能性角质层。此项研究首次在单子叶植物中发现了与角质运转相关的ABCG全转运子的基因，此前仅在拟南芥中发现2个与角质运转有关的ABC半转运子ABCG11/ABCG12。Eibi1基因编码ABC转运蛋白G亚家族的一个全转运子HvABCG31，DNA序列全长11693bp，位于大麦染色体3H上，其表达主要出现在苗期伸长区的幼叶组织中。Eibi1基因功能的缺失会导致叶片表皮细胞中脂质成分的大量积累，叶片表面角质层变薄，角质含量减少，同时角质层结构不完整，叶片失水快，保水抗旱能力差。
该项研究对单子叶植物的抗旱及角质层合成等相关研究有重要意义。Eibi1同源序列存在于单子叶植物水稻、双子叶植物拟南芥、裸子植物卷柏、苔藓及藻类中，显示出Eibi1在陆生植物进化中的重大意义。
生物探索推荐英文论文摘要：
An ATP-binding cassette subfamily G full transporter is essential for the retention of leaf water in both wild barley and rice
Abstract
Land plants have developed a cuticle preventing uncontrolled water loss. Here we report that an ATP-binding cassette (ABC) subfamily G (ABCG) full transporter is required for leaf water conservation in both wild barley and rice. A spontaneous mutation, eibi1.b, in wild barley has a low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. Map-based cloning revealed that Eibi1 encodes an HvABCG31 full transporter. The gene was highly expressed in the elongation zone of a growing leaf (the site of cutin synthesis), and its gene product also was localized in developing, but not in mature tissue. A de novo wild barley mutant named “eibi1.c,” along with two transposon insertion lines of rice mutated in the ortholog of HvABCG31 also were unable to restrict water loss from detached leaves. HvABCG31 is hypothesized to function as a transporter involved in cutin formation. Homologs of HvABCG31 were found in green algae, moss, and lycopods, indicating that this full transporter is highly conserved in the evolution of land plants.
