Mining Heat Stress Associated Genes in Tomato Fruit （Solanum lycopersicum L.） Through RNA-seq

Tomato （Solanum lycopersicum L.） is a thermophilic vegetable crop,but sensitive to high temperature stress,especially under the greenhouse conditions.Due to global climate changes,heat stress has now become a great threat to tomato production and fruit quality.Many studies have been conducted to determine the functions of genes in tomato responsive to abiotic and biotic stresses,but transcriptomic information on heat stress responses of tomato fruit is still limited.To investigate heat stress associated genes in tomato fruit,a cDNA library was constructed using fruit harvested from tomato cv.P19-9 plants grown under 42℃ for 0,1,2 and4 h and the expression profiles of heat stress responsive genes in tomato fruit were analyzed through RNA-seq.A total of 632 224 558 clean high quality paired-end reads were obtained and then mapped to reference genome for RNA-seq analysis.After quality control analysis,alignment analysis and transcript assembly,a total of 55 457 RNA transcripts were obtained with functional annotations.Overall,6 869 differentially expressed genes （DEGs） were identified with a significant response to one or more of the three heat stress treatment times.Based on GO enrichment analysis,22 genes potentially involved in tomato thermo-tolerance were selected and validated for their expressions through qPCR.The expression profile of tomato fruit genes obtained in this study could shed light on the mechanism and gene editing breeding projects for tomato thermo-tolerance.These findings could also benefit improvement of harvest and storage of tomato in greenhouse.