Transcriptome analysis of peach fruit under 1-MCP treatment provides insights into regulation network in melting peach softening

Peach(Prunus persica L.)displays distinguish texture phenotype during postharvest,which could be classified into three types,including melting flesh(MF),non-melting flesh,and stony-hard.MF peach would soften rapidly with an outbreak of ethylene production,which causes huge wastage during fruit transportation and storage.1-Methylcyclopropene(1-MCP)was used to alleviate fruit softening.In this study,we performed RNA-sequencing on two MF peach cultivars(‘YuLu’and‘Yanhong’)after 1-MCP treatment to identify the candidate genes participating in peach fruit softening.A total of 167 genes were identified by weighted gene coexpression network analysis and correlation analysis that could respond to 1-MCP treatment and might be related to softening.Among them,5 auxin-related genes including 2 indole-3-acetic acid,1 auxin response transcription factor and 2 small auxin-up RNAs,and 4 cell wall modifying genes(PpPG1,PpPG2,PpPG24 and PpPMEI)were characterized as key genes participating in MF peach softening.Furthermore,2 transcription factors,which belong to HD-ZIP and MYB,were predicted as candidates regulating softening process by constructing a transcriptional network of these 4 cell wall modifying genes combined with expression pattern analysis,of which HD-ZIP could trans-activate the promoter of PpPG1.