Characterization and expression analysis of a MADS box gene, HoMADS2, in Hyacinthus orientalis L.

A MADS box gene HoMADS2 was cloned from Hyacinthus orientalis L. in this study. Sequence comparison revealed that HoMADS2 was highly homologous to the class B MADS box genes. Furthermore, phylogenetic analysis showed that HoMADS2 was closely related to PI gene family and this was also supported by the presence of specific diagnostic sites of PI homologs in K box domain and C terminal region,suggesting that HoMADS2 might be a PI-like gene. HoMADS2 mRNA was accumulated in all floral organs,different from the expression patterns of PI homologs in dicots. During in vitro flower development, HoMADS2 expression was constitutively expressed and not affected by the presence of cytokinin and auxin in the regenerated flowers. Our results indicated that the expression of HoMADS2 is different from those of both HAG1 and HoMADS1 in responding to plant hormones during in vitro flower development.