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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01564

Transcription factor CsWIN1 regulates pericarp wax biosynthesis in cucumber grafted on pumpkin

 Jian Zhang1,  Yang Jingjing1, Yang Yang1, Jiang Luo1, Xuyang Zheng1,  Changlong Wen1, 2* and  Yong Xu1*
  • 1Beijing Vegetable Research Center, China
  • 2Beijing Academy of Agricultural and Forestry Sciences, China

Pericarp wax of cucumber is an important economic trait, determining sales and marketing. Grafting of cucumber onto pumpkin rootstock (Cucurbita moschata) is an effective way to produce glossy cucumber fruits. However, the molecular regulation mechanism of this phenomenon remains largely unknown. In the present study, transcriptome analyses, genome-wide DNA methylation sequencing, and wax metabolite analysis were performed on the pericarp of self-rooted versus grafted cucumber. We identified the AP2/ERF-type transcription factor CsWIN1 as methylated and significantly upregulated in grafted cucumber compared to self-rooted cucumber. The increased expression of CsWIN1 was also positively correlated with several key wax biosynthesis genes, including CsCER1, CsCER1-1, CsCER4, CsKCS1, and the wax transporter gene CsABC. The transcriptome expression level of these genes was validated through qRT-PCR profiles. Furthermore, wax metabolite analysis showed that more wax ester (C20 fatty acid composition), but fewer alkanes (C29 and C31) were deposited in grafted cucumber pericarp. The higher expression of CsWIN1 and wax biosynthesis genes was reflected in the glossier appearance of grafted pericarp, possibly the result of higher wax ester content and higher integration of small trichomes in the pericarp. This study demonstrates that grafting can affect the content and composition of pericarp wax in cucumber grafted on pumpkin, and a unique regulation model of CsWIN1 for wax biosynthesis may exist in cucumber.

Keywords: CsWIN1, Methylation, Transcriptome, pericarp wax, Grafted cucumber

Received: 15 Jun 2019; Accepted: 07 Nov 2019.

Copyright: © 2019 Zhang, Jingjing, Yang, Luo, Zheng, Wen and Xu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Prof. Changlong Wen, Beijing Vegetable Research Center, Beijing, 100097, Beijing Municipality, China, wenchanglong@nercv.org
Prof. Yong Xu, Beijing Vegetable Research Center, Beijing, 100097, Beijing Municipality, China, xuyong@nercv.org