Flax Wilt Biocontrol SF1’s Prediction Of Biocontrol Gene Function

B. Atrophaeus SF1 isolated by laboratory was our research object.First,we measured the growth characteristics of strain SF1.Second,we determined inhibition effect of SF1 to flax blight pathogens which came from different provinces.Finally, we screened potential bio-control gene from the whole genome sequence of SF1.In this paper, the main research contents and results were as follows:1. We mapped the seed growth curve and fermentation growth curve of the strain SF1.The seed culture conditions was as follows:37℃,150 r/min11h.The fermentation culture conditions was as follows:the quantity of 1%,32℃,150 r/min 24 h.2. We measured and analysised the whole genome sequence of strain SF1 by the Illumina MiSeq sequencing platform.Results showed that the strain SF1 genome size was 4,143,714 bp and coding protein sequence was 3,615,237 bp,which held 87.2% of the whole genome. We got the β-1,3 glucanase gene by PCR and found that β-1, 3 glucanase gene was 1086 bp.Compared its gene with β-1,3 glucanase gene with yhflE of Bacillus atrophaeus UCMB-5137 genetic,we found the similarity was 95% which proved that the whole genome sequencing results are true and correct.3.After protein annotation, SF1 genome contained multiple antibiotics, including bacteriocins compounded by ribosome (subtilosin,mycosubtilin,epidermin,etc.) and anti-bacterial enzymes (chitinase,β-1,3-glucanase and protease,etc.).It also included non-ribosomal synthesis of lipopeptide antibacterial substances (surfactin and fengycin) and bacilysin; and also found the gene cluster PKS which synthesized polyketide antibiotics bacillaene and the gene ytpA which synthesized by phospholipids antibiotic bacilysocin. We also found the Catechol-type siderophore bacillibactin and five genes closely related to swarming colonization, respectively as swrA, flgB, efp, srfA and cheB.4.Comparison the whole genome sequencing information with Bacillus atrophaeus 1942 reference genome, we found five different genes,predicted that may be related to SF1 biocontrol function. And the 5 genes were enoyl-CoA hydratase synthesized by polyketide biosynthesis, polyketide synthases, subunit A synthesized by antifungal subtilisin, superoxide dismutase and catechol-type siderophores siderophore synthetase.