Effects Of Transgenic Maize C0030.3.5 On The Community Of Soil Nitrogen Cycle Key Function Microbes

In this paper,the quantitative real-time(qPCR)and terminal fragment polymorphism(T-RFLP)technology were combined with statistical analysis to study the transgenic maize C0030.3.5 on the structure and abundance of the key functional microbial community of soil N cycle.Provide the theoretical basis for the comprehensive evaluation of the ecological and environmental risk of transgenic maize C0030.3.5.The main results are as follows:1.The dominant populationsof soil nitrogen fixation microorganisms,AOB and AOA of the transgenic maize,maize receptors and conventional maize were the same,only the proportion of their respective samples was different,the community structure did not change significantly.2.Depend on the analysis of amo A gene diversity index of AOB and AOA andnif H geneof soil nitrogen fixing microorganisms,it has been found that the results of different years and different regions were different.The experimental results of Heibei province showed that except the Shannon index and Evenness index of the nif H gene in the non-rhizosphere soil of the transgenic maize C0030.3.5 in the jointing stage and the late-ripening period of 2015 had significant difference compared with conventional maize and Shannon index of non-rhizoshphere soil in the late-ripening period of 2016 had significant difference compared with that of maize receptors and conventional maize(P <0.05),the others all showed no significant difference between.The Shannon index of AOA of in the non-rhizosphere soil of the transgenic maizein the late-ripening period of 2015 was significantly different from that of recipient maize and conventional maize(P <0.05).The results of Jilin showed that the Shannon index and Evenness indexof the nif H gene of transgenic maize were not significantly different from those of the conventional maize and the recipient maize in the same growth period(P> 0.05).The results of AOA analysis were same as nitrogen fixation microorganisms.For AOB,there was no significant difference exceptthe Shannon index of AOA of in the non-rhizosphere soil of the transgenic maize C0030.3.5 and conventional maize in the late-ripening period of 2015(P <0.05).The overall analysis showed that the two species diversity indices of the three functional microbes did not show a consistent change pattern throughout the growth period.3.The RDA analysis showed that the key physiochemical impact factors of soil microbial biomass,ammonia oxidizing bacteria and ammonia-oxidized archaea were changed in different years and in different regions.The experimental resultsog Heibei showed that the change of soil nitrogen fixing microbial community structure was significantly correlated with NH4+-N and NO3--N in 2015.The changes of AOB and AOA community structure were significantly correlated with p H,total nitrogen and nitrate nitrogen.In 2016,Ammonium nitrogen,nitrate nitrogen,water content and organic matter were the key factors affecting the microbial community structure of soil nitrogen fixation.The community structure of AOB was significantly affected by available phosphorus,total phosphorus,ammonium nitrogen,nitrate nitrogen and organic matter.The changes of AOA community structureis are the result of the combined effect of water content,nitrate nitrogen,total nitrogen,total phosphorus and p H.The results showed that soil water content was the key factor to control the change of soil nitrogen fixation microbial community structure.The soil AOB community structure was significantly affected by soil water content in 2015,and the change of AOA community structure wasjoint influenced by soil p H and water content.And p H was the main controlling factor affecting the structural change of AOB community in 2016,while the AOA community structure was significantly affected by p H.4.In the same growth phase,nif H genes of the transgenic maize C0030.3.5 soil,amo A gene abundance of AOB and AOA were not significantly different from maizereceptor and conventional maize,but the growth period has a significant influence on the abundance of soil nif H genes and amo A genes.The results above studies point out that the cultivation of the transgenic maize C0030.3.5 has no significant effect on soil nitrogen-fixing microorganism,AOB and AOA community structure and abundance.The change of soil nitrogen-fixing microorganism,AOB and AOA community structure and abundance were significantly affected by maize growth period,and the soil sampling area had no obvious effect on the change.