RESUMO
A healthy soil ecosystem is essential for nutrient cycling and energy conversion, and the impact of exogenous genes from genetically modified crops had aroused wide concerns. Phytase transgenic corn (i. e., the inbred line BVLA430101) was issued a bio-safety certificate on 27 September 2009 in China, which could improve the efficiency of feed utilization, reduce environmental pollution caused by animal manure. In this study, the abundance of trophic groups, community structure and ecological indices of soil nematodes were studied over the growing cycle of phytase transgenic corn (ab. transgenic corn) and control conventional parental corn (ab. control corn) in the field. Totally 29 and 26 nematode genera were isolated from transgenic corn and control corn fields, respectively. The abundances of bacterivores and omnivores-predators, the total number of soil nematodes, and the Shannon index (H) were significantly greater under transgenic corn than under control corn, while the opposite trend was found for the relative abundance of herbivores and the maturity index (Sigma MI) of soil nematodes. Repeated-measures analysis of variance (ANOVA) did not detect any significant effects of transgenic corn on the composition and abundance of nematode trophic groups and ecological indices of soil nematodes. Furthermore, the Student-T test showed that the abundances of bacterivores and omnivores-predators and the total number of soil nematodes during the milk-ripe stage were significant higher in the transgenic corn field than in the control corn field. The effects of transgenic corn planting on soil nematodes might be related to the increase in the nitrogen content of field soil under transgenic corn compared to control corn.
