Large-scale Screening And Phenotypic Diversity Of Two-component Signaling Systems Deletion Mutants From Lonsdalea Populi

The bacterial canker disease caused by Lonsdalea populi has serious threats to the production of Populus euramericana plantation in China.The known two-component signal transduction system(TCSTS)is one of the most important signal transduction pathways for the pathogenic bacteria of this disease,and it is an important way for them to regulate the life activities of their own cells and physiological and biochemical reactions,as well as to sense the stimulation and response of external environmental signals.The whole genome sequencing and bioinformatics analysis results of L.populi N-5-1,has been found that the strain has 42 members of two-component signal transduction system,including 18 Histidine kinase and 24 response regulator,and the deletion mutation of 6 genes has been completed,their molecular mechanism and functional have been studied.In this study,homologous recombination and phenotypic difference analysis were used to find that different members of the two-component transduction system play different roles in the growth,stress resistance,swimming ability,biofim formation and pathogenicity of pathogenic bacteria.The results are as follows1.36 target genes pWM91:HK/RR recombinant vectors in TCSTS of L.populi N-5-1were constructed on a large scale;The deletion mutation of 28 of the target genes was successfully completed,and the L.populi N-5-1 deletion mutant library was established;2.The 28 deletion mutants had different functions in the regulation of pathogenic capacity,growth rate,mobility,biofilm formation,and resistance to environmental stress(metal ions,salt ions,high permeability,antibiotics,etc.).Most genes are involved in regulating the resistance of pathogenic bacteria;five genes are involved in the regulation of growth factors;eight genes affect swimming;twelve genes are involved in the regulation of biofilm formation;the loss of nineteen genes affects the pathogenic ability,eight of them completely lost the pathogenic ability of pathogenic bacteria.3.By analyzing the phenotypic results of each deletion mutant strain and the WT strain,several multipotent genes involved in the regulation of L.populi pathogenic capacity and various phenotypes were selected.In this study,the two-component signal transduction system of L.populi N-5-1 was taken as the object to explore its correlation with the pathogenic capacity of pathogenic bacteria,so as to provide experimental materials for the further study of the molecular functional mechanism of its regulation and the search for potential target sites of new fungicides,so as to formulate effective and low-toxicity prevention and control strategies.