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Article|01 Jun 2021|OPEN
Transcriptome and physiological analyses provide insights into the leaf epicuticular wax accumulation mechanism in yellowhorn
Yang Zhao1,2,3, Xiaojuan Liu1, Mengke Wang1, Quanxin Bi1, Yifan Cui1 & Libing Wang1,
1State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, 100091 Beijing, China
2State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101 Beijing, China
3University of Chinese Academy of Sciences, 100039 Beijing, China

Horticulture Research 8,
Article number: 134 (2021)
doi: 10.1038/hortres.2021.134
Views: 510

Received: 18 Nov 2020
Revised: 03 Mar 2021
Accepted: 14 Mar 2021
Published online: 01 Jun 2021

Abstract

Plantations and production of yellowhorn, one of the most important woody oil and urban greening trees widely cultivated in northern China, have gradually become limited by drought stress. The epicuticular wax layer plays a key role in the protection of yellowhorn trees from drought and other stresses. However, there is no research on the mechanism of wax loading in yellowhorn trees. In this study, we investigated the anatomical and physiological characteristics of leaves from different germplasm resources and different parts of the same tree and compared their cuticle properties. In addition, the different expression patterns of genes involved in wax accumulation were analyzed, and a coexpression network was built based on transcriptome sequencing data. Morphological and physiological comparisons found that the sun leaves from the outer part of the crown had thicker epicuticular wax, which altered the permeability and improved the drought resistance of leaves, than did shade leaves. Based on transcriptome data, a total of 3008 and 1324 differentially expressed genes (DEGs) were identified between the sun leaves and shade leaves in glossy- and non-glossy-type germplasm resources, respectively. We identified 138 DEGs involved in wax biosynthesis and transport, including structural genes (such as LACS8, ECH1, and ns-LTP) and transcription factors (such as MYB, WRKY, and bHLH transcription factor family proteins). The coexpression network showed a strong correlation between these DEGs. The differences in gene expression patterns between G- and NG-type germplasm resources under different light conditions were very clear. These results not only provide a theoretical basis for screening and developing drought-resistant yellowhorn germplasm resources but also provide a data platform to reveal the wax accumulation process of yellowhorn leaves.