Flowering time regulation by the miRNA156 in the beet (Beta vulgaris ssp. maritima)

Successful reproduction of the plants is assumed as a crucial challenge for meeting nutritional needs of growing human population. One of the significant changes in the plant's life cycle is its transition from vegetative to reproductive phase. Obviously, the flowering and bolting processes are influenced by many genetic and physiological factors. In this way, several main regulatory pathways and effective genes have been identified, so far. The age-dependent phenomenon as an effective pathway of reproductive transition phase is influenced by the miR172 and miR156 genes. In the present study, the miR156 sequence was identified in the sugar beet genome. First, the miR156 gene was cloned into the over-expression construct from the Beta vulgaris genome and then, was transferred to the beet explants. After the confirmation of transgenic plants, the transcript level of miR156 gene, and its target genes (SPL4 and SPL9) were evaluated in transgenic plants related to the control plants. Also, transgenic plants were studied in terms of flower phenotypic development, and root growth characteristics. By evidence evaluation, the research revealed that over-expression of miR156 played an effective role in reduction of SPL4 and SPL9 genes' expression that resulted in flowering suppression in the Sea beet. According to the findings, it had also a suppression effect on the root growth in transgenic beets.