Correlation Analysis Between Virulence With SNP Of Pel In Soft Rot Bacteria In Chinese Cabbage

Brassica campestris L.ssp.pekinensis originated in China,which is one of the important vegetable crops in cruciferous.The Erwinia.carotovorum subsp.carotovorum typically causes soft rot to Chinese cabbage,which is responsible for the soft rot,blackleg,or stem rot of a number of economically important crops has a broader host range.Erwinia.carotovorum subsp.carotovorum is the most important soft rot subspecies.Different varieties of Chinese cabbage have different resistance to the soft rot.There have been some report about identification and phylogenetic diversity of soft rot bacteria in Chinsese cabbage.But the report about their pathogenic genes,is very little.In this paper,I isolated 15 Ecc strains by the conventional method.Then I cloned the 16s rDNA,go to BLAST,and identified they are Ecc.According to the sequences of PelA,PelB published on the NCBI design primers.,and clone the sequences.in Ecc strains.to do the SNP analysis.The main conclusions are as following:1.The 15 Ecc strain is divided into four pathotypes,? type:Ecc 1,Ecc 2,Ecc 6;? type:Ecc 9,Ecc 10,Ecc 11,Ecc 13,Ecc 15;? type:Ecc 4,Ecc 5,Ecc 8,Ecc 12,Ecc 14,? type:Ecc 7.2.In the 15 Ecc strains:there are 18 SNP and 11 indel in PelA,19 SNP and 4 indel in PelB.3.Virulence of Ecc strains showed extremely significant correlation with pectinase activity.Disease index of Ecc on the sense host A-78 with pectinase activity r=0.91**(**p<0.01);Pathogenic type with pectinase activity:r=0.96**(**p<0.01).4.Pectinase activity showed significant correlation with PelA.at lbp indel(G),r=0.60*(*p<0.05)and 6bp indel(T)r=-0.78**(**p<0.01);at 471bp A-G r=0.65*(*p<0.05);with PelB at 7bp A-G,11bp Indel(A)and 1087bp T-A showed significant correlation,correlation coefficient:r=0.65*(*p<0.05).5.Disease index of Ecc on the sense host A-78 with PelA at 6bp indel(T)showed extremely significant correlation,correlation coefficient:r=-0.72**(**p<0.01).Pathotype of Ecc showed significant correlation with PelA at lbp indel(G),6bp indel(T),correlation coefficient separately:r= 0.61*(*p<0.05),r=-0.63*(*p<0.05)?6.Disease index of Ecc on the sense host A-78 and Pathotype of Ecc with SNP of PelB showed no significant correlation..