| Plant pests are a global ecological problem and continue to threaten the ecological resources necessary for human survival.Controlling pests is a necessary means to increase plant yields.The planting area of poplar plantations in my country ranks first in the world,and cultivating insect-resistant poplar varieties will be of great significance to the control of forest pests in my country.Our laboratory has successfully transferred the Bt Cry1 Ac gene into Populus × euramericana ev.‘ 74/76 ’,and launched a genetically modified environment release test in 2015.In this study,4 strains of PB1,PB2,PB3,and PB9 of transgenic Eurasian poplar 107 that were grown in the field for 4 years were used as treatments,and non-transgenic Eurasian poplar 107 was used as a control.The arthropod community composition,community characteristics,and soil were investigated in each area.Microbial composition and community diversity,systematically exploring the safety of transgenic poplars,provide a more comprehensive theoretical basis for the safety of genetic breeding of transgenic forests.The main findings are as follows:(1)Transformation of insect-resistant genes has an impact on the growth of O.U.U.P.107.Compared with the control 107 poplar,the growth of the transgenic 107 poplar in tree height,branch height,DBH,crown width and other indicators were significantly lower than that of the control 107 poplar.It was preliminarily judged that the transgenic insect-resistant gene inhibited the growth of O.U.U.P.107.(2)The analysis of the plant community structure of the transgenic insect-resistant poplar107 showed that the total number of individuals in the plant community of the transgenic107 poplar was higher than that of the control 107 poplar,and there was no significant difference in the number of species between the two groups.The dominant species in the 5blocks were the same.It is a gramineous plant.Comparing the community characteristic indexes of each group and combining the results of the analysis of variance,it was found that there was no significant difference in the diversity characteristic indexes,indicating that the transgenic 107 poplar had no effect on the understory plant community.(3)A comparative analysis of the composition and structure of the arthropod community of the transgenic insect-resistant gene 107 poplar.The arthropod statistics of the transgenic107 poplar and the control 107 poplar showed that the number of lepidopteran insects in the transgenic 107 poplar arthropod community was greatly reduced,and the number of hymenopteran insects increased significantly,indicating that the transgenic 107 poplar had a significant inhibitory effect on the target lepidopteran insects effect.The number of subcommunities of pests in the transgenic 107 poplar arthropod community was greatly reduced,the number of sucking insects and natural enemies increased slightly,and the number of neutral insects increased significantly.(4)The effect of transgenic insect-resistant poplar 107 on the functional groups of arthropod communities.Compared with non-transgenic 107,the species abundance of transgenic 107 poplar decreased in each line,and the species with the largest decrease was Lepidoptera;the median species abundance of transgenic 107 poplar increased in each line.The abundance of the top species has a small change.(5)The effect of insect-resistant gene 107 poplar on arthropod community characteristic index and community stability.The arthropod community characteristic index showed that the shannon index and evenness index of the control 107 poplar were the largest,and the dominance concentration index was the smallest.The analysis of variance showed that there was no significant difference in the community structure of the other transgenic lines and the control 107 poplar except for the 9 strain.Due to the flow of insects in the forest,the dynamic change of the community characteristic index is not obvious,but compared with the control 107 poplar,the stability of the arthropod community in each transgenic 107 poplar line is higher.(6)Analysis of soil microbial community composition of transgenic insect-resistant gene107 poplar.The analysis results show that the soil bacteria of transgenic 107 poplar are mainly composed of Rokubacteria,Bacterioidetes,Firmicutes,Verrucomicrobia,Gammatimonadetes,and Chlorocurvate The composition of Chloroflexi,Acidobacteria,Proteobacteria,Planctomycetacia,Actinobacteria is the same as that of the control 107 Populus.(7)The effect of transgenic insect-resistant poplar 107 on soil microbial diversity.By comparing and analyzing the soil microbial diversity index of the transgenic 107 poplar and the control 107 poplar,it was found that the Chao1 index,Shannon index,Simpson index and ACE index of soil bacteria were not significantly different.The analysis of differences between and within groups showed that there was no significant difference in soil microbes between the transgenic 107 poplar and the control 107 poplar.(8)The results of cluster analysis of soil microorganisms of transgenic insect-resistant 107 poplar showed that the differences of soil microorganisms between the groups were not obvious,which was consistent with the results of PCoA analysis,and the relationship of soil microorganisms between the groups was close. |
