Effects Of Transgenic Phytase Maize On Diversity Of Soil Microbial Groups And Soil Enzyme Activities

Phytases are enzymes of phytic acid and phytate hydrolysis of inositol and phosphate(salt) referring to a kind of enzyme. Phytase is phosphoric monoester hydrolases which hasspecial structures with the function of separation of phytic acid phosphorus in phytic acid(salt), the degradation of inositol and inorganic phosphorus, and releasing of other nutrientsbinding with phytic acid (salt).Maize is one kind of the important crop, the expression of phytase gene in maize hasimportant significance. Transgenic phytase maize can increase the content of phytase andorganic acid in root exudates of maize plants, thereby reducing the amount of application ofphosphorus fertilizer in the soil. Transgenic phytase maize has the vital significance to avoidmore serious environmental pollution and reducing the production cost of corn. In recentyears, with the rapid development of transgenic corn, transgenic phytase maize has enteredthe field of commodity production, its security problem attracts more and more attention. Atpresent, domestic and foreign scholars on the safety detection of phytase transgenic maizemainly focus on food safety, while on the effects of transgenic phytase corn to environmentalsecurity is not involved.The soil is an important aspect of environmental safety, so we designexperiments to analyze soil microbial community diversity and the influence of soil enzymeactivity in transgenic phytase maize.The transgenic phytase maize10TPY005and its parental non-transgenic maize weregrown in field to study the quantitative changes of culturable microorganisms and thediversity of bacterial functional groups at developmental and strawing stages in2011. And westudied the soil activities including the soil sucrose activity, soil protease activity, soil ureaseactivity and the soil acid phosphatase activity at developmental and strawing stages underfield condition in2011.(1) The diversity of the same bacterial functional groups in the same stage of transgenicphytase corn was similar compared to non-transgenic maize and blank control, but thediversity of different bacterial functional groups varied during different developmental stages;(2) The quantity of ammonifying bacteria was significant higher in developmental stagethan in strawing stage, however, the quantity of aerobic cellulose-decomposing bacteria andaerobic nitrogen fixing bacteria were fewer in developmental stage than in strawing stage;(3) There were significant differences of quantity in different bacterial functional groupsduring different stages. Across the whole growth period the three population characteristic parameters (Simpson index, evenness index and the Shannon-Wiener index) keep stable. Indevelopmental stage, the population characteristic parameters of the microorganisms inphytase corn were higher than those in non-phytase corn except at trumpet stage. Thepopulation characteristic parameters of strawing stage were significant lower compared to thedevelopmental stage.(4) There were no significant differences in soil sucrose activity, soil protease activityand soil urease activity between transgenic phytase maize field and non-transgenic maize fieldin all growing stages and strawing stages in2011.(5) There were significant differences in soil acidic phosphatase activities between thetransgenic phytase maize and non-transgenic maize fields at developmental and strawingstages. The soil acidic activities of transgenic phytase maize fields were significant higherthan that of the non-transgenic maize fields showing gradual increase starting from theseedling stage while soil acidic phosphatase activity of the non-transgenic maize fieldsretained unstable.