| Bacillus nematocida B16 is a nematode bio-control strain which was screened from oil, it has strong killing activity for variety of plant parasitic nematodes. Previous studies found that: B16 use volatile substances attract nematodes to swallow it, relying on the protease of the secretion to hydrolyze the protein of nematodes intestinal epithelial cell,then destroy the host intestinal structure and function and this led to the death of the host in the end. Among them, the colonization of B16 in the host is one of the key steps in infection. Now it’s not clear what are the important genes at work in the process of colonization.1.this study construct constitutive expression strain B16g-22,and then use transposon TnYLB-1 build random mutation library of B16g-22,we get 5103 transformations in the end.2.Then we screening the randon mutation library of B16g-22, we select 27 mutatnt strains which has a low nematicides and colonization ability.We have get the sequece information around insertion sites of transposon with reverse PCR technology.Total 22 potential regulatory genes were obtained, which play an important role in the process of colonization.These genes may be roughly grouped under the following categories: spore formtion genes; spore germination genes; adhesion related genes; chemotactic movement related genes;host immune related genes; regulation of genes;function of the unknown genes.3.Based on the reports of the spore’s importance in the process of infection, this study select the global regulatory gene spo0 A which related spore formtion as target gene, we analyze the function of spo0 A gene.Compared B16g-22 with PA31,we find that PA31’s attract andcolonization ability to nematodes has a clear decline.This suggests that spo0 A gene play a key role in the process of attact and colonization ability.The experimental results for spo0 A gene’s knockout and complementary experiment laid a foundation,and provide supports for buliding effective bio-control strain. |
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