Isolation of ripening-related genes from ethylene/1-MCP treated papaya through RNA-seq

BMC Genomics

Research Article

Jiao Jiao Geng¹  Fei Ying Yang¹  Xiao Jing Chen¹  Yan Hong Shen¹  Li Feng¹  Bing Guo Lu²  Ray Ming³ 

[1] College of Horticulture, Fijian Agriculture and Forestry University, 350002, Fuzhou, Fujian, China;Institute of Genetics and Breeding in Horticultural Plants, Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian, China;College of Life Sciences, Fujian Normal University, 350117, Fuzhou, Fujian, China;FAFU and UIUC-SIB Joint Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian, China;Department of Plant Biology, University of Illinois at Urbana-Champaign, IL61801, Urbana, USA;

关键词: Carica papaya;    Firmness;    Coloration;    Transcriptome;    Ethylene;    1-MCP;   

DOI  :  10.1186/s12864-017-4072-0

 received in 2016-11-18, accepted in 2017-08-16,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundSince papaya is a typical climacteric fruit, exogenous ethylene (ETH) applications can induce premature and quicker ripening, while 1-methylcyclopropene (1-MCP) slows down the ripening processes. Differential gene expression in ETH or 1-MCP-treated papaya fruits accounts for the ripening processes. To isolate the key ripening-related genes and better understand fruit ripening mechanisms, transcriptomes of ETH or 1-MCP-treated, and non-treated (Control Group, CG) papaya fruits were sequenced using Illumina Hiseq2500.ResultsA total of 18,648 (1-MCP), 19,093 (CG), and 15,321 (ETH) genes were detected, with the genes detected in the ETH-treatment being the least. This suggests that ETH may inhibit the expression of some genes. Based on the differential gene expression (DGE) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, 53 fruit ripening-related genes were selected: 20 cell wall-related genes, 18 chlorophyll and carotenoid metabolism-related genes, four proteinases and their inhibitors, six plant hormone signal transduction pathway genes, four transcription factors, and one senescence-associated gene. Reverse transcription quantitative PCR (RT-qPCR) analyses confirmed the results of RNA-seq and verified that the expression pattern of six genes is consistent with the fruit senescence process. Based on the expression profiling of genes in carbohydrate metabolic process, chlorophyll metabolism pathway, and carotenoid metabolism pathway, the mechanism of pulp softening and coloration of papaya was deduced and discussed. We illustrate that papaya fruit softening is a complex process with significant cell wall hydrolases, such as pectinases, cellulases, and hemicellulases involved in the process. Exogenous ethylene accelerates the coloration of papaya changing from green to yellow. This is likely due to the inhibition of chlorophyll biosynthesis and the α-branch of carotenoid metabolism. Chy-b may play an important role in the yellow color of papaya fruit.ConclusionsComparing the differential gene expression in ETH/1-MCP-treated papaya using RNA-seq is a sound approach to isolate ripening-related genes. The results of this study can improve our understanding of papaya fruit ripening molecular mechanism and reveal candidate fruit ripening-related genes for further research.

【 授权许可】

CC BY   
© The Author(s). 2017