Abstract
In Arabidopsis thaliana, inflorescence-stem begins to elongate toward proper direction. We found that misexpression of LEAFY ( LFY) in cormbosa1/big and induction of LFY led to defects in orientation of pedicel and fruit. Further analyses revealed that ectopic LFY activation displayed defects in differential growth of pedicel and overproliferation of xylem elements. Correlated well with these phenotypes, ectopic expression of REVOLUTA, which is a regulator of polarity and xylem development, was observed when LFY was activated.
To understand gene cascade, we focused on APETALA1 ( AP1), a direct target of LFY and revealed that the defects in orientation in plant activating AP1 in ap1 were weaker than those in LFY in lfy or ap1. Our results show that the proper control of LFY expression not only through AP1 but more importantly through other components affects polarity and xylem development and thus ensures the appropriate orientation of pedicel and fruit.
