Abstract
Phytochoromes are red/far-red light receptors, loss of which leads to various phenotypes including early flowering. To examine tissue-specific functions of phytochrome B (phyB), we expressed phyB-GFP in tissue/organ specific manners in the Arabidopsis phyB deficient mutant (PBT lines; Nakamura et al., the 41st JSPP Annual Meeting).
Analysis of the PBT lines revealed that phyB-GFP expressed in mesophyll cells effectively delayed the flowering. In the phyB mutant, expression of the FT gene, a positive regulator of flowering, is increased (pablo et al., 2003). We examined the FT expression in different organs (cotyledon, shoot apex, hypoocotyl and root) in the PBT lines. Consequently, we found that phyB-GFP in mesophyll cells down-regulated the FT expression in cotyledons. The FT expression is restricted to vascular bundle (Takada et al., 2003). We are now examining the FT expresion at the tissue level in these lines by using the micro dissection method and/or protoplasts.
