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

Abstract Plants subjected to mild heat stress can acquire thermotolerance. But little is known about the how a grape changes, at the transcription level, after heat acclimation. In this study, we compared the transcriptome data of grape leaves after heat treatment between heat-acclimatized and non-heat-acclimatized plants, in order to detect the molecular mechanism of the acquired thermotolerance. Heat acclimation significantly relieves the heat injury of grape, with lower relative electrolyte leakage (REL) and higher Fv/Fm in heat-acclimatized plants. A total of 1526 shared genes (854 up- and 672 down-regulated) were in heat treatment (H) and heat acclimation treatment (HA), and 3533 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 macromolecule metabolic processes. Abscisic acid (ABA) signaling pathway was activated by H and HA treatment. Meanwhile, 25 heat shock proteins (HSPs), 11 antioxidase genes, and 31 transcription factor genes were up-regulated. Notably, heat acclimation suppressed sucrose metabolism pathway, and sucrose synthase (SUS) and sucrose phosphate synthase 3 (SPS3) were down-regulated. The nucleotide excision repair (NER) pathway was activated by HA treatment, and 8 genes in this pathway were induced. Heat acclimation also activated the cysteine biosynthesis pathway, in which serine acetyltransferase 1 (SAT1) and S-sulfocysteine synthase (SSCS) expressed at high levels. Transcriptomic profiling reveals transcriptional alterations in heat-acclimatized and non-heat-acclimatized grapevines under heat stress, which provides a new insight into the plant response to heat acclimation.