The Functional Verification Of The Serine Proteases Of Rice Blast Fungus In Rice

The rice blast fungus, Magnaporthe grisea is one of the most important rice pathogens. The interaction of M. grisea and rice is also taken as a model for the study of fungus-plant interaction. The interaction involves a complex process of signal recognition and transduction in response to each other. It is reported that most of the pathogenic elicitors and virulence factors of pathogens are secreted proteins. There are many researches showed that the Serine Proteases of M. grisea is a potential pathogenic factor.Our previous researche had confirmed that the MGG₀7965.5 gene may have a very important biological function. The MGG₀7965.5 gene has a larger expression strength. The further bioinformatics analysis indicates that it is a secreted proteins and that it has a signal peptide of 20 amino acid residues.In the research, we sequenced the cDNA and found that the intron which shown in the gene dabatase of MGG₀7965.5 gene may be an exton of the MGG₀7965.5 gene. In order to further understand the fungus-plant interaction, we constructed two transient expression vectors: pUPTN-F-07965.5 and pUPTN-C-07965.5. The forme contains the full length MGG₀7965.5 gene while the later contains the MGG₀7965.5 gene which has its signal peptide removed. I also constructed another two over expression vectors pCAMBIA1301-ubi-F-07965.5 and pCAMBIA1301-ubi- C-07965.5.We used Particle Bombardment to co-expression the transient expression vector and 1301 vector in the leaves of CO39 and its near isogenic line variety Pi9. The result showed that the expression strength of GUS gene is significant lower in Pi9 than in CO39. But it is interest in that there is no the MGG₀7965.5 gene which has its signal peptide cut. Significant difference were observed in the expression strength of GUS gene wether the signal peptide been cut or not. Based on that we believe that the Serine proteases gene MGG₀7965.5 is a potential pathogenic factor of M. grisea. The product of it may be one of an elicitors which induces the hypersensitive response of blast resistance rice. Two over-expression vectors was also transferred into rice variety Minghui 86 and 12 transgenic rice plants were obtained, which contain the full length gene and 16 transgenic rice plants which contain the MGG₀7965.5 gene which has its signal peptide removed. We harvested the plants which are positive in the biological assay for the futher research.