Functional Analysis Of A Leucine-rich Repeat Receptor-like Kinase(LRR-RLK) Subfamily Gene Atlg09970 In Arabidopsis

Receptor protein kinase (RPKs) are important mediators of paracrine signaling in metazoans.The completion of the Arabidopsis Genome Initial(AGI) project revealed that this plant contains a much larger counterpart of receptor kinase genes than other organisms does. So far no functional information is available for the majority of theses proteins,so they were named as receptor-like kinase(RLK).The genes in RLK can be classified into many subfamilies based on the extracellular structure traites, and LRR-RLK (leucine- rich repeat)subfamily is the largest. Studies on some members of LRR-RLK genes showed that they play very important role in the regulation of plant development and stress-resistance. Atlg09970 is a LRR-RLK gene,and encondes a 976aa protein, which contains 12 LRR motifs in its extracellular domain by protein structure prediction analysis . This study describes the results of At1g09970 cDNA cloning, expression pattern of the transcript, subcellular location, and the phenotypic observations of the mutants and overexpression transgenic plants as follows.1. The At1g09970 cDNA clone was obtained by RT-PCR method. After sequenced, the cDNA ORF fragment was subcloned into pBI121 and transformed to the wildtype arabidopsis (Col.0) by Agrobacterium-mediated transformation method. to get the over-expression transgetic plants Compared with wild arabidopsis,the overexprssion transgetic plants had notable predominance in root elongation in plate culture.2. Tht gene expression pattern by semi-quantitive RT-PCR showed that it expressed during the whole stages of the plant growth and development and its expression pattern was affected by the environmental factors. 3.Three homozygous T-DNA mutants were identified at DNA and RNA levels by PCR and RT-PCR. Then the phenotype of the mutants were observed at the stages of germination and postgermination. The result revealed that Atlg09970 mutants were sensitive to NaCl suggested that this gene may participate in salt-stress resistance process in plant.4. Meanwhile, the fluorescent signal of Atlg09970::GFP fusion protein was detected under confocal fluorescence microscope and possibly located in the plasmamembrane, suggesting that Atlg09970 may plays role in the plasmamembrane.