Cuticular wax is a natural barrier on terrestrial plant organs, which protects plants from damages caused by a variety of stresses. Here, we report the identification and functional characterization of a cuticular‐wax‐related gene, Zea mays L. SEMI‐ROLLED LEAF 5 (ZmSRL5). The loss‐of‐function mutant srl5, which was created by a 3,745 bp insertion in the first intron that led to the premature transcript, exhibited abnormal wax crystal morphology and distribution, which, in turn, caused the pleiotropic phenotypes including increased chlorophyll leaching and water loss rate, decreased leaf temperature, sensitivity to drought, as well as semi‐rolled mature leaves. However, total wax amounts showed no significant difference between wild type and semi‐rolled leaf5 (srl5) mutant. The phenotype of srl5 was confirmed through the generation of two allelic mutants using CRISPR/Cas9. ZmSRL5 encodes a CASPARIAN‐STRIP‐MEMBRANE‐DOMAIN‐LIKE (CASPL) protein located in plasma membrane, and highly expressed in developing leaves. Further analysis showed that the expressions of the most wax related genes were not affected or slightly altered in srl5. This study, thus, primarily uncovers that ZmSRL5 is required for the structure formation of the cuticular wax and could increase the drought tolerance by maintaining the proper cuticular wax structure in maize.

中文翻译：

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ZmSRL5通过维持玉米的表皮蜡结构参与抗旱性。

表皮蜡是陆地植物器官上的天然屏障，可保护植物免受各种胁迫造成的损害。在这里，我们报告了表皮蜡相关基因Zea mays L. SEMI-ROLLED LEAF 5（ZmSRL5）的鉴定和功能表征。功能丧失突变体srl5是由在第一个内含子中插入3,745 bp导致早熟转录物产生的，表现出异常的蜡晶体形态和分布，进而导致多效性表型，包括增加的叶绿素浸出和失水率，降低的叶片温度，对干旱以及半卷成熟叶片的敏感性。但是，野生型和半卷叶5（srl5）突变体之间的蜡总量没有显着差异。通过使用CRISPR / Cas9产生两个等位基因突变体，证实了srl5的表型。ZmSRL5编码位于质膜上的CASPARIAN-STRIP-MEMBRANE-DOMAIN-LIKE（CASPL）蛋白，在发育中的叶片中高度表达。进一步的分析表明，大多数与蜡有关的基因的表达在srl5中没有受到影响或轻微改变。因此，这项研究主要揭示了ZmSRL5是形成表皮蜡的结构所必需的，并且可以通过维持玉米中合适的表皮蜡结构来提高抗旱性。