Abstract
Pharbitis nil cv. Violet is an ideal plant for the study of photoperiodic induction of flowering because the seedling can be induced to flower by a single short-day treatment. Among numerous physiological data of this system, we noticed that the flowering process needs gene expression. We have examined the changes in gene expression during and just after the flower-inductive photoperiod and identified several genes as candidates of flowering genes. PnC401 encodes pentatricopeptide repeat protein. The product of the Arabidopsis homologue, AtC401 can interact with CO protein in yeast. We also identified the CO homologue, PnCO. Then, we isolated FT homologues as candidates of the down stream of PnCO and found that there are two FT homologues in Pharbitis, namely, PnFTL (Leaf-type) and PnFTA (Apical-type). Their patterns of expression were consistent with the physiological data of the induction of flowering in Pharbitis. We will carefully discuss relationship of PnFTs and florigen.
