科研之友
微信
新浪微博
Facebook
分享链接
摘要
Members of the MADS-box gene family are known to play critical roles in regulating flower development in angiosperms. To expand our knowledge of flower development in monocots, and to elucidate the molecular mechanisms involved in floral development in onion (Allium cepa), we have isolated a putative C-function flower homeotic identity gene AcAG (GenBank ID: JX974431). Genomic DNA analysis showed that AcAG is a single-copy gene in the onion genome that appears to have lost a conserved intron during evolution. Sequence comparison and phylogenetic analysis revealed that AcAG gene is a homolog of Arabidopsis AGAMOUS, and is closely related to C-lineage AG homologs in monocot species. Moreover, the predicted AcAG protein possesses a typical MIKC domain and two highly conserved sequence motifs (AG motifs I and II) specific to the C proteins in the variable C-terminus, but the N-terminal extension that is usually present in the eudicot euAG lineage was not found. Transcription of AcAG, determined by semi-quantitative PCR, was detected only in flowers and was absent in vegetative tissues such as roots, stems, and leaves. Real-time PCR analysis showed that AcAG was expressed specifically in stamens and carpels of flowers, and had spatial and temporal expression patterns in the two inner reproductive whorls. This is consistent with the expression patterns observed for AG-like genes in other species. All these results indicate that AcAG is the onion ortholog of Arabidopsis AGAMOUS, and that it may play an important role in regulating development of the reproductive organs in onion.
