Journal of Integrative Agriculture ›› 2017, Vol. 16 ›› Issue (07): 1486-1501.DOI: 10.1016/S2095-3119(16)61501-0

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  • 收稿日期:2016-07-25 出版日期:2017-07-20 发布日期:2017-07-06

Genome-wide identification, characterization, and expression analysis of the SWEET gene family in cucumber

HU Li-ping1, 2, ZHANG Feng1, SONG Shu-hui1, TANG Xiao-wei1, XU Hui1, LIU Guang-min1, WANG Ya-qin1, HE Hong-ju1, 2   

  1. 1 Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P.R.China
    2 Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing 100097, P.R.China
  • Received:2016-07-25 Online:2017-07-20 Published:2017-07-06
  • Contact: Correspondence HE Hong-ju, Tel: +86-10-51503068, Fax: +86-10-51505002, E-mail: hehongju@nercv.org
  • About author:HU Li-ping E-mail: huliping@nercv.org
  • Supported by:

    This research was supported by the National Natural Science Foundation of China (31301792), the Beijing Natural Science Foundation, China (6142010) and the Youth Scientific Research Funds of the Beijing Academy of Agriculture and Forestry Sciences, China (QNJJ201401).

Abstract:     SWEETs (sugars will eventually be exported transporters) are a novel class of recently identified sugar transporters that play important roles in diverse physiological processes. However, only a few species of the plant SWEET gene family have been functionally identified. Up till now, there has been no systematic analysis of the SWEET gene family in Cucurbitaceae crops. Here, a genome-wide characterization of this family was conducted in cucumber (Cucumis sativus L.). A total of 17 CsSWEET genes were identified, which are not evenly distributed over the seven cucumber chromosomes. Cucumber SWEET protein sequences possess seven conserved domains and two putative serine phosphorylation sites. The phylogenetic tree of the SWEET genes in cucumber, Arabidopsis thaliana, and Oryza sativa was constructed, and all the SWEET genes were divided into four clades. In addition, a number of putative cis-elements were identified in the promoter regions of these CsSWEET genes: nine types involved in phytohormone responses and eight types involved in stress responses. Moreover, the transcript levels of CsSWEET genes were analyzed in various tissues using quantitative real-time polymerase chain reaction. A majority (70.58%) of the CsSWEET genes were confined to reproductive tissue development. Finally, 18 putative watermelon ClaSWEET genes and 18 melon CmSWEET genes were identified that showed a high degree of similarity with CsSWEET genes. The results from this study provided a basic understanding of the CsSWEET genes and may also facilitate future research to elucidate the function of SWEET genes in cucumber and other Cucurbitaceae crops.

Key words: cucumber ,  gene expression ,  phylogenetic analysis ,  sugar transporter ,  SWEET ,  watermelon