Contents lists available at ScienceDirect Plant Physiology and Biochemistry journal homepage: www.elsevier.com/locate/plaphy Research article Transcriptome analysis of Chinese bayberry (Myrica rubra Sieb. et Zucc.) fruit treated with heat and 1-MCP Ting Shi a ,JieSun a,b , Xinxin Wu a , Jinyang Weng a , Pengkai Wang b , Hongli Qie b , Yinghong Huang b , Huakun Wang b , Zhihong Gao a,∗ a Nanjing Agricultural University, No. 1 Weigang, Nanjing, 210095, PR China b Taihu Extension Center for Evergreen Fruit of Jiangsu Province, Eastern Mountain Town, Suzhou, 215107, PR China ARTICLEINFO Keywords: Chinese bayberry 1-MCP Transcriptome analysis Postharvest storage ABSTRACT Chinesebayberry(Myrica rubra Sieb.etZucc.)isatypicalfruittreegrowninthehillyregionofSouthernChina. The fruit is sensitive to storage and transportation conditions and presents a major problem in its commercia- lization. The present study was conducted to investigate the regulation of gene expression involved in plant hormonesignalingpathwayintheChinesebayberrywithdiferenttreatmentsofheatand1-methylcyclopene(1- MCP) during postharvest storage. In one treatment group (HM group), we exposed Chinese bayberry fruit to 48°Cfor10minandthensealedtheminadesiccatorwith5μl·L -1 of1-MCPfor24hat20°C,followedbystorage at 10°C. Another group (CK group) was directly stored at 10°C without any prior treatment. Samples of fruit werecollectedeverythreedays,at3,6,9,12and15d(CK3,CK6,CK9,CK12andCK15;andHM3,HM6,HM9, HM12,andHM15,respectively).ThedecayindexoffruitsintheCKgroupincreasedaftersixdaysofstoragebut didnotincreaseuntilninedaysofstorageintheHMgroup.Superoxidedismutase(SOD)activityintheCKgroup wasshownadowntrendduringstorage,andalmostnofuctuation fromsixdays.IntheHMgroup,SODactivity increased after three days, but decreased sharply after six days storage. Besides, peroxidase (POD) and catalase (CAT)activitieswereshownthesimilartrendduringthestorage,bothofthem frstincreasedandthendecreased form the six days of storage. These physiological data indicated that the sixth day is a crucial time during the storage of Chinese bayberry treated with heat and 1-MCP. Therefore, the transcriptome libraries were con- structed from CK0, CK6, HM6 group, respectively. The analysis of top 20 KEGG pathways showed that most diferentiallyexpressedgeneswereinvolvedinthebiosynthesisofsecondarymetabolites,particularly favonoids andfavanolsbiosynthesis,inCK0vs.CK6andCK0vs.HM6.However,thetopthreeKEGGpathwaysinCK6vs. HM6weretheribosome,RNAtransportandendocytosisduringthestorage.Expressionofsixethylenereceptor (ETR)genesandfourethylene-responsivetranscriptionfactor(ERF)geneswereactivatedattranscriptionallevel during the postharvest stage and were decreased by heat and 1-MCP treatment, and serine/threonine-protein kinase 1 (CTR1) was also repressed by treatment. Abscisic acid (ABA) -responsive element binding factor (ABF) gene, auxin-responsive GH3 gene and transcription factor MYC2 gene also showed similar expression pattern withethylenepathwaygenes.Theseresultsmightimproveourunderstandingofthemechanismsofheatand1- MCP inhibition of fruit postharvest physiology and prolongation of fruit shelf life. 1. Introduction Chinese bayberry (Myrica rubra Sieb. et Zucc.) is a typical fruit tree grown in the hilly region of Southern China, with an extensive cultivation history (Chen et al., 2004; Yang et al., 2007). Chinese bayberry fruit has higheconomicandmedicinalvalue(Chengetal.,2008; Xieetal.,2009).Its peel is very thin and with no exocarp protection. Moreover, its ripening stage depends on the rainy season with high temperature and humidity (Zhang et al., 2005). Fruit respiration and the aging process are very fast and the fruit becomes soft and juicy at this stage. The fruit is susceptible to mechanical damage, water loss, physiological deterioration and microbial decay, limiting its post-harvest life to few days at ambient temperature. After harvesting, the fruit hardness decreases due to mycelium respiration andmetabolism,seriouslyafecting fruitnutrition(Yangetal.,2007; Zhang et al., 2005). The fruit is sensitive to storage and transportation conditions and this presents a major problem that restricts its commercial develop- ment. Therefore, present-day commercial cultivation remains largely re- stricted to Southern China (Chen et al., 2004). Most of the bayberry fruit https://doi.org/10.1016/j.plaphy.2018.10.022 Received 22 May 2018; Received in revised form 17 October 2018; Accepted 17 October 2018 ∗ Corresponding author. E-mail address: gaozhihong@njau.edu.cn (Z. Gao). Plant Physiology and Biochemistry 133 (2018) 40–49 Available online 24 October 2018 0981-9428/ © 2018 Elsevier Masson SAS. All rights reserved. T