Different expression of limonene synthase gene in organs and developmental stages of cumin (Cuminum cyminum L.)

In this study, limonene synthase (Ls) gene expression was investigated with SQ-RT-PCR method in organs and also during some developmental stages of cumin (Cuminum cyminum L.) native to Iran. After culture and sampling of roots, shoots and leaves (one stage of each) and flowers (four stages of developmental phases), results revealed that this gene was expressed in very small (<2mm) and small (3-4mm) flowers in size and shoot vegetative tissue, while it was not expressed in roots, leaves, medium (4-5mm) and larger flowers. Maximum gene expression of limonene synthase was observed in shoot, very small and small flowers, respectively. During developmental stages of the flowers, LS gene expression was highest in the youngest stage, but this was gradually declined and ceased at later developmental stages. Results revealed that this gene was expressed during different growth and developmental phases from two leaves to flowering of intact plants, with an increase during generative phase that confirmed synchronize gene expression on both vegetative and reproductive organs. Partial sequencing of limonene synthase gene revealed that cumin is 58%-64% identical to that of some other plants. Anatomical studies indicated that essential oil ducts were located on the fruit tissue. The overall results of the present research showed high expression of LS gene in young reproductive organs, while the high level of expression in shoot vegetative tissue and during whole period of plant life cycle was a remarkable point.