Study On Labeling Biocontrol Bacteria Bacillus ZA1 With GFP And Its Colonization

In order to study the colonization of ZA1 in the root of potato and rhizosphere soil, the vector with GFP was transformed into biocontrol bacteria ZA1 and the stability was tested. Then the safety evaluation was used for studying microbial interaction in soil. The main results are as follows: 1 Transformation of ZA1 and stability of ZA1-gfpThe vector of p GFP78 with DNA methylation was transformed into ZA1 by electroporation, the results showed that there was no difference in morphology between positive strain ZA1-gfp and ZA1, the ZA1-gfp appeared bright green under the fluorescence microscope. The stability turned out to 100 % and there was no obvious difference was found in the growth curves of ZA1 and ZA1-gfp(P<0.05). The inhibition rates of ZA1 against Fusarium avenaceum,Colletotrichum coccodes and Phoma foveata were 64.5%,68.35% and 66.55%, respectively, and the inhibition rates of ZA1-gfp against Fusarium avenaceum,Colletotrichum coccodes and Phoma foveata were 67.46%,76.56% and 66.75%, respectively, which indicated that genetic transformation had no effect on the antibacterial effect of biocontrol bacteria. In addition, the results revealed genetic transformation was beneficial to colonization because it had no effect on the motility of ZA1. 2 The colonization of ZA1-gfpZA1-gfp could be colonized well in soil with a density of 3.68 ′ 104 to 7.31 ′ 104 cfu/g. In non sterile soil, ZA1-gfp could be colonized in the root of potato and rhizosphere with a density of 4.86 ′ 101 to 6.3 ′ 102 cfu/g and 2.97 ′ 103 to 1.46 ′ 105 cfu/g, respectively. In sterile soil, ZA1-gfp could be colonized in the root of potato and rhizosphere with a density of 2.42 ′ 101 to 1.16 ′ 102 cfu/g and 2.44 ′ 102 to 2.38 ′ 103 cfu/g, respectively. Significant analysis indicated no obvious difference found in two neighbouring data of all colonization dynamics of ZA1-gfp in 60 days(P<0.05). Meanwhile, ZA1-gfp could be colonize on the root epidermis, root hair and root transverse section of potato with bright green bacteria based on the fluorescence microscopy observation. Otherwise, ZA1-gfp had showed obviously growth-promoting effect(P<0.05). 3 The effect of ZA1-gfp on soil microorganismIn non sterile soil, IR were 1349.1, 2163.74 and 1293.47 for 15, 25 and 35 days later after ZA1-gfp inoculation, the results showed that the soil microbial number was increased significantly(P<0.05). In sterile soil, IR were-9.26, 53.17 and 1249.45 for 15, 25 and 35 days later after ZA1-gfp inoculation, which indicated that the soil microbial number was increased after ZA1-gfp inoculation.In non sterile soil, the number of soil bacteria, fungi and actinomycetes was 3.66×108~2.63×109 cfu/g, 2.38×104~2.50×105 cfu/g and 8.11×104~6.32×105 cfu/g, respectively. In sterile soil, the number was 3.15×108~4.22×109 cfu/g, 1.46×105~5.23×105 cfu/g and 1.41×104~3.65×105 cfu/g, respectively. Significant analysis indicated no obvious difference found in two neighbouring data of soil microbial dynamics(P<0.05). There was no harm effect on soil microorganisms after ZA1-gfp inoculation and the community stability of soil microorganisms was kept well.