Functional Analysis Of Two-component Signal Transduction System Genes LqHK1 And LqRR2 In Lonsdalea Quercina

Poplar bacterial canker caused by Lonsdalea quercina subsp.populi N-5-lwas a disease that was a seriously harm to poplar industry.The disease is mainly harm to the Populusxeuramerieana'Neva' and Populus×euramericana'zhonglin 46'.Resulting in branches and treetops dead,seriously affecting the health of poplar and wood production,there is no effective control measures.The study of the pathogenicity mechanism of the pathogen will help to develop effective control technology and the new drug target sites.In this paper,by studying the two-component system signal gene in pathogen pathogenic mechanism and the function of the biological processes,to understanding the function of the biochemical and pathogenic mechanism of histidine protein kinase LqHK1 and the regulatory regulatory LqRR2.The results are shown below:Through the bioinformatics analysis of the LqHK1 sequence,the suicide plasmid pWM91-?LqHK1 was constructed according to the principle of homologous recombination,and then LqHK1 deletion mutant was obtained.The results showed that LqHK1 was a single copy,The code area is 1350 bp,encoding 450 amino acids.Biological characteristics showed that the pathogenicity of the deletion mutant of LqHKl gene was significantly decreased on 107 branches of Populus xeuramericana'Neva,,while the complemented mutant HBLqHK1 restored the virulence to the wild-type leve.Mutant in the amount of bacteria in vivo host colonization was significantly less than the wild type strain.Further analysis showed that the swimming ability of the mutant strain and the biofilm formation ability were significantly different from those of the wild type strain.But the gene deletion had not affect the growth rate of the strain,the ability of extracellular polysaccharide and Cellulase formation ability.The LqRR2 mutants of L.quercinaN-5-1 were also obtained.The results showed that LqRR2 was a single copy,The code area is 1419 bp,encoding 473 amino acids.Biological characteristics showed that the pathogenicity of the deletion mutant of LqRR2 gene was significantly decreased on 107 branehes of POPulus ×euramericana'Neva,,while the complemented mutant HBLqRR2 restored the virulence to the wild-type leve.Mutant in the amount of bacteria in vivo host colonization was significantly less than the wild type strain.Phenotypic analysis found that Mutant strain swimming ability than wild-type decreased,And by qRT-PCR analysis,The motility related genes flgB,flgC,flgE expression significantly decreased in mutant but the growth rate of LqHK1 mutant strains and wild type had no significant difference.