Isolation, sequencing and expression levels of FLOWERING LOCUS C ortholog gene (FLC) in different organs of Sisymbrium irio (Brassicaceae)

Regulation of flowering time requires the activity of various genes that are controlled by environmental and internal cues. The FLC gene plays a key role in transition to flowering and suppresses flowering as target gene of vernalization pathway. Vernalization is a natural adaptation to ensure flowering after winter so that flowers and seeds can develop in favorable environmental conditions. In this study, identification and expression of FLC gene was investigated in rocket mustard (Sisymbrium irio). Total RNA was extracted from cotyledon leaves and cDNA was made. Specific primers were designed based on tsequence alignment of FLC homogenous genes and used for RT-PCR reaction. The identified 449 nucleotids fragment was recorded as SiFLC with accession number KT156751 in the NCBI database. Sequencing of the coding region and comparison of its putative protein (with 150 amino acids) and FLC orthologues in other plants showed their high similarity. Expression relative rate using the semi-quantitative method, in vegetative stage in young leaves, mature leaves, stems and roots was between 56-86%, which the highest (about 86%) and the lowest (about 56%) levels were observed in young leaves and stems respectively. In the reproductive stage, a decrease in expression was observed in these organs especially in leaves (about one percent). However, expression level was higher in flower buds and reached about 31%. Decreasing leaf expression in the reproductive phase indicates flowering induction. FLC higher levels in flowers, after transition to flowering, allows the next generation to reregulate its rate and respond to winter during vegetative phase