miR395 is involved in response to cold stress and modulation of sulfate and phosphate deficiency in Grape (Vitis vinifera)

Low temperature is a major abiotic stress which can significantly affect the grape production. microRNAs play an important role in the control of plant development and response to adverse environmental conditions. Although miRNAs and their targets have been identified in several Vitis species, their participation during cold accumulation remains largely unknown. One such microRNA is miR395, which is conserved and regulates sulfate assimilation and distribution in plants. In this study, the possible role of miR395 in cold stress response was investigated. Identification of target genes, gene ontology and biological system analysis were performed to identify the major networks in which this miRNA is involved. Finally, the effects of gradual chilling and also a shock chilling on the expression of miR395 were investigated. In total, five target genes were identified, which all of them are targeted by miR395s a to m, whereas of the five target genes, only one is identified by miR395n as a target. Three of these genes, including ATP sulfurylase, sat-1 and, LAST3-like are involved in the control of sulfur metabolism and transport. Pathway analysis showed that miR395 was involved in response to cold stress in grape through cellular response to sulfate and phosphate deficiency. Based on RT-PCR results, contrary expression patterns of miR395 under gradual (up-regulated) and shock chilling stress (down-regulated) were observed. The changes of sulfate assimilation process would influence the formation of sulfur-containing antioxidant compounds. These results provide an insight into the regulatory roles of miR395 in response to low-temperature stress in V. viniferae.