Effect Of Rhizosphere Microbe On Chemotaxis Of Root-knot Nematode

Rhizosphere microorganisms attract two nematodes(Meloidogyne incongnita,Caenorhabditis elegans)and their effect on chemotaxis of Meloidogyne incongnita in tomato roots were studied.The results are as follows:One hundred and two strains of actinomycetes and 150 rhizosphere bacteria were screened chemotaxis of M.incognita.There are four strains showed chemotactic ability to the M.incognita,and the chemotaxis index reached 0.21,0.21,0.26 and 0.31.The strain G-2 was identified as Streptomyces plicatus.Fermentation broth of strain G-2 had a chemotactic effect on C.elegans at 24 h and on M.incognita at 72 h.The volatile compounds produced by G-2 were identified by GC-MS.Trans-1,10-Dimethyl-trans-9-decalol(105 ppm)and Dibenzofuran(103ppm)had negative chemotaxis on C.elegans.Benzothiazole(106 ppm,I05 ppm,104 ppm,103 ppm)and Trans-1,10-Dimethyl-trans-9-decalol(104 ppm)had positive chemotaxis on C.elegans.Benzothiazole(104 ppm)had negative chemotaxis on M.incognita.Dibenzofuran(104 ppm)had positive chemotaxis on M.incognita.The soil with fermentation broth of strain G-2,2-35,1-50,5-14 and 6-4’showed a chemotactic effect on the M.incognita,respectively.The soil with Decanal(103 ppm),Trans-2-hexenal(104 ppm),Dibenzofuran(104ppP)showed positive chemotaxis on M.incognita.The soil with Trans-2-hexenal(103 ppm),Benzothiazole(104 ppm)showed negative chemotaxis on M.incognita.Chemotaxis effect were enhanced when G-2,2-35,5-14,6-4 ’fermentation broth were put into tomato roots.And the chemotaxis ability of M.incognita increased 15%,25%,26%and 20%,Decanal(103 ppm),Trans-2-hexenal(104 ppm),dibenzofuran(104 ppm)increased the chemotaxis ability of M.incognita at 33%,38%,32%on tomato roots.Chemotaxis effect were weakened slightly when 1-50,5-14 fermentation broth and Benzothiazole(104 ppm)were put into tomato root.Highlight of this research:1.Streptomyces plicatus were proved to be have attractive ability towards the M.incognita at 72 h and negative to the C.elegans at 24 h.It was confirmed that Benzothiazole and Trans-1,10-Dimethyl-trans-9-decalol(104ppm)produced by S.plicatus can attract to C.elegans.Dibenzofurans can attract M.incognita.2.It was found that five rhizosphere bacteria and their metabolites could increase the chemotaxis ability of M.incognita in tomato roots.