| Grain yield of maize is a complex quantitative trait,and is determined by kernel number and kernel weight.Kernel shape and kernel size both determine kernel weight and control grain yield.Therefore,recognizing genes which are related to the development of kernel,and analyzing the relationship between the development of kernel and grain yield both are important to understand the molecular mechanisms of grain yield in maize.In this study,a maize gene named Zm MADS-RIN encoding MADS-box protein which controls kernel development was isolated.Reviewed the protein of Zm MADS-RIN with an emphasis on bioinformatics intervention,studied the specific expression and the expression pattern of Zm MADS-RIN by RT-PCR and real-time fluorescent quantitative PCR,respectively.The main research results are as follows:1.The results of sequencing showed that the full length c DNA of Zm MADS-RIN is 859 bp,and contained an open reading frame(ORF)which possesses 768 nucleotides and encodes 255 amino acid residues.The variables analysis of Zm MADS-RIN between Zheng 58 and B73 in coding region showed that there are 6nucleotides and 3 amino acid residues are different.2.Bioinformatics analyses showed that Zm MADS-RIN is a hydrophilic protein which has a molecular weight of 29.23 k D,a theoretical isoelectric point of 8.84,and5 phosphorylation sites,but it has no signal peptide sequence or transmembrane domain.The secondary structure of Zm MADS-RIN protein was Alpha helix: 50.20%,Random coil: 27.45%,Extended strand: 14.51% and Beta turn: 7.84%.Subcellular localization prediction showed that Zm MADS-RIN was localized to nucleus.Amino acid sequence analysis indicated that Zm MADS-RIN protein contained the highly conserved MADS domain,relatively conserved K domain,less weakly conserved I domain and most variable C domain,and it was a typical MIKC-type protein.Phylogenetic analysis indicated that Zm MADS-RIN protein belongs to the samebranch of AGL6,and shows high similarity to Os MADS6 protein from Oryza sativa,was 89%.3.RT-PCR results showed that Zm MADS-RIN was highly expressed in kernel,and there was no signal in root or leaf during different phases.4.In addition,we analyzed the expression of Zm MADS-RIN by real-time fluorescent quantitative PCR during the different phases of developing kernel,and the results indicated that in Zheng 58,the expression of Zm MADS-RIN increased continually from zero day to 20 days after pollination,and reached the highest level at the 20 th day,then decreased significantly.And it could not be detected during30th-40 th days.These results demonstrated that Zm MADS-RIN might be associated with the regulation of developing kernel in maize. |
