AUTHOR=Liu Dechun , Guo Wenfang , Guo Xinyue , Yang Li , Hu Wei , Kuang Liuqing , Huang Yingjie , Xie Jingheng , Liu Yong 

TITLE=Ectopic Overexpression of CsECR From Navel Orange Increases Cuticular Wax Accumulation in Tomato and Enhances Its Tolerance to Drought Stress

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.924552

DOI=10.3389/fpls.2022.924552

ISSN=1664-462X

ABSTRACT=<p>Drought stress often occurred in citrus to limit its growth, distribution, and fruit quality. Cuticular waxes play an important role in regulating plant tolerance to drought stress. Plant enoyl-CoA reductase (ECR) is involved in the biosynthesis of cuticular waxes and catalyzes the last step of very long-chain fatty acids (VLCFAs) elongation. In this study, a putative <italic>ECR</italic> gene, named <italic>CsECR</italic>, was cloned from “Newhall” navel orange. <italic>CsECR</italic> protein has high identities with other plant ECR proteins and contained a conserved NADP/NAD-binding motif and three conserved functional sites. The highest expression of <italic>CsECR</italic> was observed in leaves, followed by stems, flavedos, ovaries, juice sacs, stigmas, stamens, albedos, and petals. Besides, the expression of <italic>CsECR</italic> was significantly induced by PEG6000 and ABA treatments. Ectopic overexpression of <italic>CsECR</italic> increased the contents of total waxes and aliphatic wax fractions (<italic>n</italic>-fatty acids, unsaturated fatty acids, <italic>n</italic>-alkanes, alkenes, iso-, and anteiso-alkanes) in the leaves and fruits of the transgenic tomato. Furthermore, ectopic overexpression of <italic>CsECR</italic> reduced the cuticle permeability in the leaves and fruits of the transgenic tomato and increased its tolerance to drought stress. Taken together, our results revealed that <italic>CsECR</italic> plays an important role in plant response to drought stresses by regulating cuticular wax biosynthesis.</p>