Effects of long-term cultivation of transgenic Bt rice (Kefeng-6) on soil microbial functioning and C cycling

Abstract

Understanding how soil ecosystem responds to transgenic Bacillus thuringiensis (Bt) rice is necessary for environmental risk assessment. While the influences of short-term cultivation of Bt rice on soil properties have been reported previously, little is known about the long-term effects of Bt rice on soil ecosystems. In this study, soil samples were taken from a long-term rice cultivation site in Fujian Province, China, where transgenic Bt rice (Kefeng-6) and its non-Bt parent breed (Minghui-86) had been continuously cultivated for 8 years. Soil Bt protein concentration and a total of 16 variables were analyzed to assess potential risks of soil health under Bt rice cultivation. The results revealed that soil Bt protein is unlikely to accumulate after Bt rice cultivated in the field, and no consistently significant changes were observed in soil enzymatic activities (catalase, dehydrogenase, acid phosphatase, and urease), microbial biomass (microbial carbon and nitrogen), total organic carbon, decomposition (soil respiration, Q 10, and qCO2), soil nitrogen and phosphorus contents. Due to a local tradition that aboveground biomass was removed after harvest, the increased net primary productivity by Bt rice cultivation did not significantly change soil C cycling. Results of this study suggested that on the aspects of soil microbial functioning and C cycling, long-term cultivation of Bt rice is unlikely to result in significant effects on soil health.

The response of dominant and rare taxa for fungal diversity within different root environments to the cultivation of Bt and conventional cotton varieties

“…Further, soil pH was the strongest predictor of soil fungal community composition, followed closely by Bt protein content, suggesting that Bt protein introduced by root exudates did not impact fungal community composition more strongly than soil pH. Notably, several studies have shown that Bt protein expressed by Bt crops does not persist in the soil after long-term cultivation of Bt crops [ 10 , 47 , 48 ]. Moreover, environmental factors and cotton growth traits are specific at different growth stages, which affect the diversity and dynamics of rhizosphere microbial communities differently.…”

Effect of Two Different Sugarcane Cultivars on Rhizosphere Bacterial Communities of Sugarcane and Soybean Upon Intercropping

“…Each soil sample was divided into three parts for DNA extraction, environmental factor determination, and soil enzyme activity determination. Soil organic carbon (SOC), total nitrogen (TN), and available phosphorus (AP) content was then measured as previously described (Bremner and Tabatabai, 1972 ; Soon and Abboud, 1991 ; Zhaolei et al, 2017 ), and soil enzyme kits were used to determine soil urease (S-U), soil sucrase (S-SC), soil catalase (S-CAT), and soil acid phosphatase (S-ACP) (Wang et al, 2014 ; Hou et al, 2020 ). Each soil sample was analyzed in three replicates, 0.5 g per sample.…”

Effects of Bt-cotton on biological properties of Vertisols in central India

“…The impact of Bt-toxin on soil microorganisms is either inconsistent or negligible under various agro-climatic conditions (Kapur et al 2010;Hu et al 2013;Velmourougane & Sahu 2013). However, the continuous growing of transgenic crops in the same location might enhance the toxin's concentration to a level that might influence the composition and activity of soil microbial communities and microbiological properties (Zhaolei et al 2017;Li et al 2018). Existing literature present inconclusive data on this issue.…”