OsBIK3Regulate Growth And Disease Resistant Of Rice

Plants have developed a complex innate immunity system in the long term of evolution in plant-pathogen interaction. In plant immunity system, pattern recognition receptors (PRRs) recognize the pathogen associated molecular patterns (PAMP) and trigger the plant innate immunity, is very important for its broad spectrum and persistence. RLKs is a huge-number receptor gene in higher plant, RLCK is a special kind of RLKs with essential roles in plant growth and immunityBased on BIK1protein sequence in Aarabidopsis, we used Blastp and Tblastx to search the rice genome database (http://rice.plantbiology.msu.edu/), and identified the rice homologous gene with protein kinase conservative domain and numbering. OsBIK3(LOC_Os03g60710) is about a homology of57%with AtBIKI. We purchased the target gene T-DNA insertion mutants by searching rice mutant (http://signal.salk.edu/cgi-bin/RiceGE) with the gene sequence, and obtained the pure mutant lines using PCR and qRT-PCR. Furthermore, we identified its disease resistance and growth phenotype to reveal its function in PTI. The main results were as following:1. Full length cDNA of OsBIK3were obtained by RT-PCR and confirmed by DNA sequencing.The open reading frame (ORF) of OsBIK3is1275bp, encoding424amino acids, with6exons and5introns. The domain structure prediction found that the protein contained serine/threonine protein kinase catalytic structure domain and tyrosine structure domain.2. Using the real-time fluorescent quantitative PCR, we found that the transcript level of OsBIK3can be induced by bacteria leaf blight pathogen, JA and SA. JA and SA induced responses were quickly, with in1hour, while pathogen induced its expression after12hours to reach peak3. Using protoplast transient expression system and dual luciferase report system we found that OsBIK3could complement Arabidopsis AtBIKl function and activate the PTI, as shown by the flg22induced marker gene in Arabidopsis PTI pathway after induction FRK1expression situation.4. Using protoplast transient expression system and GFP fusion vector, we found that OsBIK3was located in cell membrane.5. We screened Osbik3mutant by PCR and RT-PCR, and identified the pure lines with decreased mRNA levels.6. We have amplified the flanking seguence of T-DNA insertion by PCR.7. The germination and plant height of mutant plants were lower than the wild type DJ, suggesting that OsBIK3was involved in plant growth and development process.8. Using live vaccine pathogen of bacterial and fungal pathogens in vitro inoculation, we found that bik3mutants in leaf blight pathogen PXO99and blast Y34after infection than wild type disease serious, showed that down-regulation of OsBIK3expression reduced the disease resistance of rice.9. We found that the mutant plants in the course of the disease related protein gene PRl, PR5, PRIO expression significantly higher than in wild type.