Analysis On Expression And Change Of MADS-box Gene In Floral Mutants Ah,dl And Their Wild-type In Rice

The most striking feature of the MADS-box gene family is the diverse functions taken up by its members in different aspects of plant growth and development. These include flowering time control, meristem identity, floral organ identity, formation of dehiscence zone, fruit ripening, embryo development as well as development of vegetative organs such as root and leaf . Most of genes controlling floral organ development belong to the MADS-box gene family. Compared with the dicot, reaserch on MADS-box gene in monocots such as rice fall behind obviously. Most of the MADS-box gene have been cloned from rice by using homeotic sequence of dicots as probe screening the rice genomic or cDNA library, and predicting their fuction through transgene or antisense RNA technique .We discovered two mutant ah(abnormal hull),dl(drooping leaf) from line 458,which was a line of the twin-seedling strain W2555.. In this study, we cloned MADS-box gene from yong panicle of the three materials and analysed their expression. The major results are summarized as follows:We cloned five MADS-box genes from these three materials, sequence analysis showed that they correspond to MADS1, MADS6, MADS7, MADS17 and MADS24. MADS7,MADS17,MADS24 sequence homology shared at least 99%, only few sites occured synonymous mutation in the three materials. MADS1 in ah,dl and MADS6 in dl occurred insertion mutation which resulted in protein sequence change .Relative quantitative assay of the five MADS-box genes expression in young panicle by realtime PCR, we found these three materials had a difference in gene expression. In the wild-type, the gene expression levels from high to low were MADS7, MADS6, MADS1, MADS24, MADS17. In ah, MADS1 and MADS6 expression were significantly higher than their expression in wild-type;the difference of MADS17 expression between wild-type and ah was not obvious; MADS7 and MADS24 expression were significantly lower than that in wild-type and about equal to dl. In dl, all the MADS-box gene expression were signifieantly lower than that in wild-type except MADS1.