| Since the introduction of Genetically Modified(GM)crops in 1996,the area of commercial planting around the world has been increasing,and people have paid great attention to their safety issues while harvesting the huge economic benefits they bring.The cultivation of genetically modified crops has potential impacts on local ecological diversity,especially the root exudates of crops may affect the activity of soil functional enzymes,the diversity of microbial functions,and the structure of bacterial communities in the soil.The soil ecosystem is a natural complex of soil organisms(including planted plants and animals and microorganisms in the soil)and their surrounding environment.The interaction between organisms and soils occurs simultaneously,and the soil microbial diversity It can be used to express the health status of soil ecosystems,and the diversity of microorganisms can affect the plant diversity associated with them.In this study,the transgenic cry1Ab-Ma gene-resistant maize CM8101(CM)and its corresponding non-transgenic receptor maize Zheng 58(CMCK)were used as experimental materials.Both materials were provided by the Chinese Academy of Agricultural Sciences,and the test site was located in the environmental safety research and test market in Changchun,Jilin.In this study,the rhizosphere soil of maize was collected in the three growth stages of seedling,flowering and maturity of maize in 2017 and 2018,respectively.It was used to study the physical and chemical properties and related functional enzymes of long-term planting of transgenic insect-resistant maize CM8101.Activity,functional diversity of microbial communities,and effects of bacterial community structure.The main findings are as follows:1.Effects of transgenic insect-resistant maize CM8101 on soil physical and chemical properties and functional enzyme activities.In this paper,two basic physical and chemical properties of water content and pH were studied.The activities of three functional enzymes,soil urease,phosphatase and catalase,were determined.The results showed that there was no significant difference in soil water content,pH value,urease,phosphatase and catalase activity between the transgenic insect-resistant maize CM8101 and non-transgenic maize Zheng 58 in three consecutive growth years.This indicates that long-term planting of transgenic insect-resistant maize CM8101 does not significantly affect the main physical and chemical properties and functional enzyme activities of the soil.2.The effect of transgenic insect-resistant maize CM8101 on the functional diversity of rhizosphere soil microbial community.In this paper,the functional diversity of transgenic insect-resistant maize CM8101 and non-transgenic maize Zheng 58 rhizosphere soil microbial community was determined by Biolog ECO plate.Biolog ECO plates were incubated for 7 days in a 25? incubator at the same time every 24 h.The absorbance of the plate was determined by microplate reader.The results showed that there was no significant difference in microbial carbon source utilization,diversity index and overall metabolic activity between the transgenic insect-resistant maize CM8101 and the non-transgenic maize Zheng 58 in two years.It was further shown that the transgenic insect-resistant maize CM8101 planted for two years did not significantly affect the functional diversity of rhizosphere soil microbial communities.3.The effect of transgenic insect-resistant maize CM8101 on the bacterial community structure of rhizosphere soil.In this paper,the bacterial community structure of transgenic insect-resistant maize CM8101 and non-transgenic maize Zheng 58 rhizosphere soil was compared by 16S rRNA amplicon sequencing.The results showed that the transgenic insect-resistant maize CM8101 and non-transgenic maize Zheng 58 rhizosphere soil in two years.There was no significant difference in bacterial community structure and bacterial community diversity,indicating that the bacterial community structure of rhizosphere soil was not affected by transgenic insect-resistant maize CM8101.In summary,long-term planting of transgenic insect-resistant maize CM8101 does not significantly affect the physical and chemical properties,functional enzyme activities,microbial community functional diversity and bacterial community structure of rhizosphere soil by comparison with non-transgenic maize Zheng 58.The results of this study have increased the understanding of the safety of transgenic insect-resistant maize CM8101,and provided a reliable theoretical basis for the future commercialization of this variety. |
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