Transcriptome analysis of grape leaves reveals insights into response to heat acclimation

Due to the global warming, heat stress has been one of the most important factors limiting grape growth and development. Plants subjected to a mild heat stress can acquire thermotolerance. But little was known on the changes of grape at transcription level after heat acclimation. In this study, we compared the transcriptome data of grape leaves after heat treatment between heat-acclimation and non-heat-acclimation plants, in order to detect the molecular mechanism of the acquired thermotolerance. Heat acclimation significantly relieved the heat injury of grape, with lower relative electrolyte leakage (REL) and higher Fv/Fm in heat-acclimation plants. A total of 854 co-up-regulated and 672 co-down-regulated genes were in heat (H) and heat acclimation (HA) treatment, and 3,533 differently expressed genes (DEGs) were unique to HA treatment. By GO analysis, DEGs in H treatment were enriched in signal transduction pathways, while DEGs in HA treatment were enriched in acromolecule metabolic processes. After H and HA treatment, ABA signaling pathway and biosynthesis of amino acid were activated; the expression levels of 29 heat shock proteins (HSPs) and 11 antioxidase genes increased; 31 transcription factors were up-regulated, including 5 HSFs, 5 AP2-EREBPs, 4 MYBs, 3 NACs and 14 other transcription factors. Notably, heat acclimation suppressed Sucrose synthase (SUS) and sucrose phosphate synthase 3 (SPS3); induced 8 genes involved in nucleotide excision repair (NER) pathway; activated the cysteine biosynthesis pathway, in which serine acetyltransferase 3 (SAT3) and S-sulfocysteine synthase (SSCS) expressed at high levels. Transcriptomic profiling reveals transcriptional alterations in heat-acclimation and non-heat-acclimation grapevines under heat stress, which provides a new insight into underlying molecular mechanism of enhanced thermotolerance by heat acclimation.