Legume Developmental Regulation Of The Apical Meristem

Abstract Bradley et al. found the CEN gene in Antirrhinum in 1996, which controls the inflorescence structure. Its mutation leads to the formation of terminal flower at apex. TFL1 gene, the homologue gene in Arabidopsis, not only result in the formation of terminal flowers but also let plant flower earlier when it mutates. Much work has been done in digging out the CEN homologues at other plant system. The CEN/TFL1 pathway restrains or retards the phase transition of SAM, which is also conserved in rice, tobacco and tomato. We try to understand the mechanism of inflorescence development in Lotus, the legume model system, through CEN homologues in it. Two pairs of primers are designed according to the conserved region of CEN gene. A fragment about 750bp is amplified from Lotus genome through nested PCR. One CEN-like gene, named Ljcen, is screened out from a genomic library based on TAC vector with the PCR fragment. RT-PCR suggests that Ljcen is expressed at the reproductive SAM. The genomic southern results at different stringency indicate that Ljcen may have only one copy in Lotus using cDNA fragment as probe. In situ hybridization tells us that Ljcen is expressed at the subdomain of primary and secondary inflorescence meristem. The ectopic expression of Ljcen in Arabidopsis retards the flowering of it. The ectopic expression and knock-out of Ljcen in Lotus doesn't show any obviously phenotype change till now. Thoroughly investigation is going on. These results suggest Ljcen gene is the homologue gene of CEN/TFL1 and function as TFL1 in Arabidopsis .