风信子HoMADS2基因的克隆及表达分析

利用同源克隆策略，从风信子中分离出一个MADS box基因，命名为HoMADS2。序列比较分析表明，HoMADS2与B类MADS box蛋白具有较高的同源性。分子进化树分析显示，HoMADS2与PI家族类聚在一起。同时，在HoMADS2的Kbox和C末端区域均具有PI家族的特征序列。以上序列分析结果表明，HOMADS2可能是尸，的一个同源基因。RNA分子杂交结果显示，HoMADS2在四轮花器官中均表达，其表达模式不同于双子叶植物中尸，同源基因。利用风信子离体花器官再生系统研究表明，HoMADS2在再生花芽中的表达不同于HoMADS1和HAG1，该基因在再生花芽发育过程中组成型表达，不受外源细胞分裂素和生长素的影响。

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 HoMADS 2 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.