旱生植物表皮发达的角质层是其防止水分散失、抵御干旱环境的有效屏障。角质层组分即蜡质和角质(合称为脂质)在表皮细胞内合成后，需经质膜运输至表皮细胞外以形成角质层；ABCG11基因编码的脂质转运蛋白是参与该过程的关键基因。目前学术界对表皮角质层脂质分泌的研究均以中生植物为对象，其表皮角质层并不发达。本项目拟以表皮角质层十分发达的荒漠旱生植物霸王为材料，在前期已克隆其脂质转运蛋白基因ZxABCG11的基础上，利用qRT-PCR技术对ZxABCG11基因在不同胁迫条件下的转录丰度进行分析；采用RNA干扰技术沉默ZxABCG11基因，测定转基因植株表皮角质层各组分含量，观察其表皮角质层及表皮细胞结构并对其耐旱性进行评价；对转基因植株及野生型霸王进行表达谱比较分析。以解析角质层脂质在荒漠植物抗旱性中的作用，为优良牧草及农作物抗旱性的遗传改良提供理论依据及抗逆基因资源。

The well-developed and thick surface cuticle is an effective barrier to restrict water loss and resist arid environments for xerophytes. Following its biosynthesis in epidermal cells, the cuticle, which is composed of wax and cutin, collectively termed cuticular lipids, was exported across the plasma membrane to the cell wall and further to extracellular matrix. In plants, ABCG11 gene encoding a plasma membrane-localized ATP-binding cassette transporter was suggested to play the most important and central role in the progress of cuticular lipids secretion, but plants used in these researches were mesophytes possessing thinner cuticle. In this project, based on the cloning of ABCG11 gene in our previous work, in order to reveal the function of cuticular lipid secretion mediated by ABCG11 transporter for drought adaptation of succulent xerophytes, taking the typical succulent xerophyte Zygophyllum xanthoxylum which has well-developed surface cuticle as material, the following experiments would be done: quantitative analyzing transcript abundance of ZxABCG11 under various stress conditions using real-time RT-PCR technique; analyzing chemical compositions of cuticular lipids in epidermis, observing the structure of cuticle and epidermal cells and evaluating drought tolerance of plants, after gene silencing of ZxABCG11 using RNA interference (RNAi) technique; comparing the gene expression profiles of ZxABCG11-silenced plants and wild-type Z. xanthoxylum. The results could provide theoretical basis and stress-resistant gene(s) for the genetic improvement of drought resistance in high quality forages and crops.