Validation Of MiR828 Target Gene And Function Analysis Of SlyMYB7-Like In Tomato

MicroRNA is a kind of endogenous non coding small RNA which is widely existed in eukaryotes. miRNAs play important roles in plant growth and development, stress and disease resistance, secondary metabolism via the regulation of their target gene. Identification and functional analysis of target genes are important to study biological functions of miRNA. miR828 is a newly discovered and conserved miRNA. The function of miR828 is mainly in Arabidopsis. In this study,we firstly identified that SlyMYB7-Like is the target gene of miR828 in tomato by RML-S’Race successfully.Second, we cloned the SlyMYB7-Like and predicted the function by bioinformatics showed that SlyMYB7-Like encodes R2R3 type of MYB transfer factor and has a high homology with AtMYB7, AmhMYB330, StuMYB6-Like. Thirdly, RT-PCR results of gene expression analysis of different tissues of tomato showed that the expression of SlyMYB7-Like was highest in fruit followed by bud, stem, flower, leaf and root. Construction of over-expression vector of SlyMYB7-Like and it expression in transgenic Arabidopsis showed purple phenotype, and the anthocyanin content and the expression level of enzymes genes related in Arabidopsis anthocyanin synthesis increased. Finally, The result of studying on transgenic Arabidopsis under drought stress showed that the water loss rate of leaf and the content of MDA in SlyMYB7-Like transgenic Arabidopsis is lower than that of wild type, however, the activities of CAT and POD were higher than wild type.In conclusion, The identification of target genes lays a foundation for further studing of the functional of miR828 in tomato, which SlyMYB7-Like could positive regulate the biosynthesis of anthocyanin and enhanced transgenic Arabidopsis’ tolerance to drought stress. The mechanism of SlyMYB7-Like positively regulated the anthocyanins biosynthesis provides a theoretical basis for the study of the regulation network of tomato anthocyanin. It has a practical significance to improve the nutritional and medicinal value of tomato. The drought resistance characteristics of SlyMYB7-Like is useful for exploring and utilizing of quality genes in stress in tomato.