Identification of differentially expressed microRNAs of sunflower seedlings under drought stress

다국어 초록 (Multilingual Abstract)

Sunflower (Helianthus annuus L.) is considered to be drought‐tolerant, the roles of microribonucleic acids (miRNAs) in the response to drought have not been thoroughly studied. In this work, differentially expressed miRNAs of sunflower seedlings under drought stress were identified, and putative target genes were predicted. Ultimately, 163 known miRNAs and 90 novel miRNAs were identified and discovered. Under drought stress, 54 and 25 miRNAs were up‐regulated and down‐regulated in leaves, while 94 and 10 miRNAs were up‐regulated and down‐regulated in roots, respectively. A total of 1788 target genes were predicted. The results of gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis of target genes indicated that 47 and 74 genes were enriched for 14 and 19 GO terms in leaves and roots, respectively. In leaf, seven genes were possibly associated with binding to meta lion, adenyl ribonucleotide, alcohol and protein, two genes with transferase activity, three genes with hormone responses, and two genes with hormone‐mediated signaling pathways. In root, 23 genes were associated with binding functions, two genes with lignin metabolic processes, and three genes with hormone responses. We also discovered 40 target genes related to spliceosome function, of which three genes may take part in deoxyribonucleic acid (DNA) replication pathways that include nucleotide excision repair, mismatch repair, and homologous recombination. Sequencing of miRNAs and digital expression spectrum demonstrated that the differential expression of 21 genes may be the results of miRNAs regulating. These findings provide new information regarding molecular mechanisms of sunflower drought responses and add to the number of plant drought tolerance genes.