Cloning And Sequences Analysis Of Genes Encoding For SSP And MLPK In S-receptor Kinase Signal Transduction

Following the wide-ranging utilization of heterosis in farming, more and more achievements in the field of SI have been made. It is certain that Brassica is one of the most prevalent farm crops, which have been studied in the process of researches on the molecular mechanism of Sporophytic self-incompatibility. After function factors, encoded by S-locus, which initiated SI signal transduction were found and their function were researched, the separation and purification of some new proteins suspected as the substrate proteins of S receptor kinase have already been made. However, some further questions must still be solved. In generally, an allele-specific interaction between SCR/SP11 and SRK induces autophosphorylation of SRK, which causes a signaling cascade in the pistil that leads to self-incompatibility signal transduction. Moreover, as the mediators of SRK signaling, ARC1, THL1/THL2 and MOD work in coordination, which leads to rejection of self-pollen. The isolation and purification of an unknown protein from Brassica oleracea by D. Wu in 2003 and MLPK from Brassica rapa by Murase in 2004 will provide new insights though the functions of these proteins have remained unknown. Using Brassica oleracea El bred by Southwest Agricultural University as materials, we cloned SSP and MLPK through a series of methods of molecular biology such as PCR, RT-PCR and 3'RACE. The sequences were highly analyzed by using the related biosoftwares on Internet. We also studied and predicted their proteins' structure and function with bioinformatical methods. The results above mentioned would provide new insights in the field of the molecular mechanism of self-incomnatibility in Brassica oleracea. The main results are as followings:1. Cloning and Sequences Analysis of SSPThe cDNA and DNA fragments of M locus encoding protein kinase were initially amplified from genomic RNA and stigma DNA in Brassica oleracea El by using 3'RACE and PCR. After they recovered, cloned into vectors and sequenced, the results demonstrated that in B. oleracea SSP cDNA and genomic DNA were 825bp and 778bp. Comparison of sequences between SSP genomic DNA and cDNA predicted that there was only one exon containing 654 bases in SSP gene and encoding 217 amino acid sequences. Homologous analysis in nucleotide sequence using BLAST demonstrated...