转cry1Ab和epsps基因玉米C0030.3.5对土壤古菌丰度和多样性的影响

为探讨转基因玉米的生态安全问题,2015年分别于玉米拔节期、抽雄期、乳熟期和完熟期采集土壤样品,并采用荧光定量PCR(Quantitative real-time PCR,q PCR)和末端限制性片段长度多态性分析(Terminal restriction fragment length polymorphism,TRFLP)技术,研究了转cry1Ab和epsps基因玉米C0030.3.5种植对土壤古菌丰度和多样性的影响。结果表明:转cry1Ab和epsps基因玉米C0030.3.5(TM)和受体玉米DBN318(PM)的根际土和非根际土古菌数量为1.41×10~9~4.04×10~9copies·g~(-1)土,随生长时期的推进均呈现先升高后降低的变化趋势,同一生长时期和土壤样品采集区域,2种玉米古菌16S rRNA基因丰度间无显著差异。T-RFLP分析共获得15种不同长度的T-RFs,其中89 bp和184 bp片段为优势种群,同一生长时期和土壤样品采集区域每种优势种群在TM和PM间均无显著差异。土壤古菌Shannon指数除PM非根际土呈现先降低后升高的变化趋势外,其他均表现为先降低后升高再降低;TM和PM根际土古菌Evenness指数的变化趋势均为先降低后升高,而非根际土古菌Evenness指数表现为先降低后升高再降低。同一生长时期和土壤样品采集区域TM和PM的Shannon指数间及Evenness指数间差异均不显著。冗余分析(Redundancy analysis,RDA)显示土壤总氮和硝态氮含量对古菌群落结构有显著影响。主成分分析(Principal component analysis,PCA)表明,TM和PM土壤古菌群落在根际土和非根际土中均未发生明显分离,说明TM和PM土壤古菌群落组成无显著差异。上述结果表明:转cry1Ab和epsps基因玉米C0030.3.5土壤古菌丰度和群落结构组成与受体玉米DBN318无显著差异,古菌丰度和多样性主要受生长时期的影响,受土壤样品采集区域的影响不显著,土壤总氮和硝态氮是调控土壤古菌群落变化的关键因子。

Effects of transgenic maize containing cry1Ab and epsps gene C0030.3.5 on the abundance and diversity of soil archaea

In order to comprehensively understand the ecological safety of transgenic maize, soil samples were collected in 2015 at the jointing, tassel, milky and ripening stage of transgenic maize containing cry1Ab and epsps gene C0030.3.5, and the effects of this maize on the abundance and diversity of soil archaea were investigated by quantitative polymerase chain reaction and terminal restriction fragment length polymorphism(T-RFLP) analyses. The results indicated that the number of archaea in the rhizosphere and non-rhizosphere zones of transgenic maize containing cry1Ab and epsps gene C0030.3.5(TM) and the parental maize DBN318(PM) was between 1.41×10⁹ and 4.04×10⁹ copies·g^-1 soil, and all showed the trend of initially increasing and then decreasing with growth stage progression. No significant difference was observed in the abundance of the archaeal 16S rRNA gene between TM and PM for the same growth stage and sampling area(P>0.05). A total of 15 terminal restriction fragments of different lengths were acquired by T-RFLP, and among these, the fragments with lengths of 89 bp and 184 bp were derived from the dominant populations. For the same growth stage and sampling area, each dominant population showed no significant difference between TM and PM(P>0.05). The Shannon index initially decreased, then increased and decreased again, with the exception of the non-rhizosphere zone of PM, which showed an initial decrease followed by an increase. The Evenness index of the rhizosphere of TM and PM initially decreased and then increased. However, in the non-rhizosphere zone of TM and PM, the Evenness index showed a decrease-increase-decrease trend. For both the Shannon and Evenness indices, there were no significant differences between TM and PM for the same growth stage and sampling area. Redundancy analysis indicated significant correlations between total nitrogen and nitrate-nitrogen and the composition of archaea. Principal component analysis indicated no significant separation between TM and PM in either the rhizosphere or non-rhizosphere zone, suggesting that there was no significant difference in the composition of archaea between TM and PM. In summary, no significant differences were found in the abundance and community structure of archaea between the transgenic maize containing the cry1Ab and epsps genes and its parental maize. The abundance and diversity indices of archaea were mainly affected by the growth stage of maize. Soil total nitrogen and nitrate-nitrogen were the key factors controlling the soil archaeal community.