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Article|01 Jun 2018|OPEN
Comprehensive analysis of NAC transcription factors and their expression during fruit spine development in cucumber (Cucumis sativus L.)
Xingwang Liu1, Ting Wang1, Ezra Bartholomew1, Kezia Black1, Mingming Dong1, Yaqi Zhang1, Sen Yang1, Yanling Cai1, Shudan Xue1, Yiqun Weng2 & Huazhong Ren1,
1Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, 100193 Beijing, P. R. China
2Department of Horticulture, USDA-ARS, Vegetable Crops Research Unit, University of Wisconsin-, Madison, WI 53706, USA

Horticulture Research 5,
Article number: 31 (2018)
doi: 10.1038/hortres.2018.31
Views: 769

Received: 04 Sep 2017
Revised: 16 Mar 2018
Accepted: 21 Mar 2018
Published online: 01 Jun 2018

Abstract

The cucumber (Cucumis sativus L.) is an important vegetable crop worldwide, and fruit trichomes or spines are an important trait for external fruit quality. The mechanisms underlying spine formation are not well understood, but the plant-specific NAC family of transcription factors may play important roles in fruit spine initiation and development. In this study, we conducted a genome-wide survey and identified 91 NAC gene homologs in the cucumber genome. Clustering analysis classified these genes into six subfamilies; each contained a varying number of NAC family members with a similar intron–exon structure and conserved motifs. Quantitative real-time PCR analysis revealed tissue-specific expression patterns of these genes, including 10 and 12 that exhibited preferential expression in the stem and fruit, respectively. Thirteen of the 91 NAC genes showed higher expression in the wild-type plant than in its near-isogenic trichome mutant, suggesting their important roles in fruit spine development. Exogenous application of four plant hormones promoted spine formation and increased spine density on the cucumber fruits; several NAC genes showed differential expression over time in response to phytohormone treatments on cucumber fruit, implying their essential roles in fruit-trichome development. Among the NAC genes identified, 12 were found to be targets of 13 known cucumber micro-RNAs. Collectively, these findings provide a useful resource for further analysis of the interactions between NAC genes and genes underlying trichome organogenesis and development during fruit spine development in cucumber.