Impact of transgenic cottons expressing cry1Ac on soil biological attributes

Abstract

Three transgenic Bt cotton hybrids (RCH-2 Bt, Bunny Bt and NHH 44 Bt) expressing cry1Ac gene were evaluated for their effects on soil biological, microbiological and diversity attributes at 0-15 cm and 15-30 cm soil depth under field conditions. At both soil depths, soil respiration rate and fluorescein diacetate hydrolysis were the highest in the soil under Bt cotton grown followed by non-Bt soil, and by the control bulk soil, indicating no adverse effects of Bt cotton on soil microbial activity. Urease and dehydrogenase activities, reflecting potentially available N and the oxidative metabolism in soil, respectively, also increased in the sequence no-crop variant < non-Bt soil < soil under Bt cotton at both soil depths. A similar trend was found with the soil microbial biomass carbon, microbial population and microbial diversity indices. These results suggest that cultivation of Bt cotton expressing cry1Ac gene may not pose ecological or environmental risk.

Salt tolerant SUV3 overexpressing transgenic rice plants conserve physicochemical properties and microbial communities of rhizosphere

“…There was not any significant difference in the enzyme activity of rhizospheric microbes of transgenic and WT plants, which corroborated with the experimental findings on Bt cotton (Mina et al, 2011). Except for the dehydrogenase enzyme activity, the activity of alkaline phosphatase, nitrate reductase and urease enzymes of Bt and non Bt plants rhizosphere were different, but this difference was not statistically significant (Velmourougane and Sahu, 2013). During the growth period (of 150 days), the activity of enzymes such as phosphatase, nitrate reductase and urease was high in the rhizosphere at early vegetative and flowering stage, whereas activity of dehydrogenase enzyme was elevated during gall formation stage.…”

Impact ofBt-cotton on soil microbiological and biochemical attributes

“…These changes may be transient depending upon soil type, crop stage, as well as environmental conditions (Velmourougane & Sahu, 2013). In Pakistan, previously no study has been conducted with primary objective to investigate the effects of growing Bt-cotton on soil microbiological and chemical attributes.…”

“…The diverse microbial communities sustain their growth in close proximity to the plant roots using decomposed organic matter and root exudates. Plant genetic transformation can alter rhizosphere chemistry (Gasson, 2000;Kowalchuk et al, 2003;Lynch et al, 2004) that can also cause distinct changes in root exudates and root structural properties (Velmourougane & Sahu, 2013).…”

Effects of transgenic Bt rice on the active rhizospheric methanogenic archaeal community as revealed by DNA-based stable isotope probing

“…; Li et al . ; Velmourougane and Sahu ; Singh et al . ), and few reports studied the effect of planting transgenic Bt plants on critical ecosystem processes and their functional microbial groups.…”

“…In addition, some ecological functions and micro-organisms seem to be more sensitive to environmental changes compared with general micro-organisms (Herold et al 2012;Han et al 2013). However, until now, most studies were concerned only with culturedependent or nonfunctional microbes Li et al 2011;Velmourougane and Sahu 2013;Singh et al 2015), and few reports studied the effect of planting transgenic Bt plants on critical ecosystem processes and their functional microbial groups.…”