Change in abuscular mycorrhizal fungi colonization rate and nutrient content in Bt corn

Changes in abuscular mycorrhizal fungi colonization rate and in nitrogen, phosphorus and potassium content in Bt corn “5422Bt11” and “5422CBCL” resulting from two different transformation events along with their non-transgenic isogenic lines “5422” were investigated. Meanwhile, the correlation between abuscular mycorrhizal fungi colonization rate and nutrient content was subjected to further analysis in this study. The results indicate no significant differences among three corn cultivars in abuscular mycorrhizal fungi colonization rate for the experiment period. Remarkable differences, however, exist between Bt and non-Bt corn in-terms of nitrogen, phosphorus and potassium content. Moreover, the correlation between abuscular mycorrhizal fungi colonization rate and nutrient content varies with corn variety, growth stage and plant organ. For Bt corn “5422Bt1”, leaf total potassium and root total phosphorus at the large trumpet stage, leaf total phosphorus and root total nitrogen at flowering stage, leaf total potassium at milk stage, and leaf total phosphorus and root nitrogen and potassium at mature stage are significantly higher than those for the non-Bt corn “5422”. On the contrary, leaf total nitrogen at large trumpet and flowering stages, root total phosphorus and potassium at flowering stage, and root total potassium at milk stage tend to decrease in Bt corn “5422Bt1”. With regard to Bt corn “5422CBCL”, leaf total potassium and root total nitrogen and potassium at large trumpet stage, leaf total phosphorus at flowering stage, and root total nitrogen and potassium at mature stage are evidently higher than those for the non-Bt corn “5422”. However, root total phosphorus at flowering stage, root total phosphorus and potassium at milk stage, and leaf total phosphorus at mature stage are relatively lower than those for the non-Bt corn “5422”. The analysis shows that abuscular mycorrhizal fungi colonization rate in non-Bt corn “5422” and Bt corn “5422CBCL” is positively correlated with root total nitrogen and leaf total potassium (P < 0.05). Contrarily, there is insignificant correlation between abuscular mycorrhizal fungi colonization rate and nutrient content in Bt corn “5422Bt1” (P > 0.05). In comparison with non-Bt corn, the findings suggest that the changes in nutrient content along with correlation variations between abuscular mycorrhizal fungi colonization rate and nutrient content of Bt corns are associated with the varietal characteristics induced by transformation process.