Characteristic analysis and function exploration of grapevine circular RNA VvcircRNA_06190 and miRNA responding to drought stress

Drought stress seriously affected the growth and berry quality of grapevine. It is important to understand the mechanism of drought response and to improve the drought resistance of grapevine. One-year old ‘Muscat Hamburg’ grapevine cuttings were used as experimental materials to conduct small RNA sequencing, degradome, circRNA sequencing and transgenic technology to reveal the characteristic and the role of miRNAs and circRNAs response to drought stress. Our results showed that during the drought stress treatment, the soil and leaf water content decreased, while the leaf electrical conductivity, SOD activity, MDA, and H 2 O 2 contents increased with the extension of the stress time; there are 46 differentially expressed miRNAs under drought, and their target genes were significantly enriched in the isoquinoline alkaloid biosynthesis, tyrosine metabolism, plant-pathogen interaction, and plant hormone signal transduction pathways; there are 184 circRNAs responding to drought, their parent genes mainly enriched in carbon fixation in photosynthetic organisms, peroxisome, endocytosis and protein processing in endolasmic reticulum pathways, and the target genes of miRNAs that bind to differentially expressed circRNAs were enriched in spliceosome, ABC transporters, and starch and sucrose metabolism pathways. Additionally, the overexpression techniques of Arabidopsis thaliana and grape callus demonstrated the circular RNA VvcircRNA_06190 enhances the drought tolerance of grapes by increasing SOD activity. The results of the present study provide evidence of the complexity of miRNA and circRNA regulatory networks in response to drought and will provide new ideas for grape breeding.