Effects of the transgenic CrylAc and CpTI insect-resistant cotton SGK321 on rhizosphere soil microorganism populations in northern China

Abstract

Transgenic CrylAc and CpTI insect-resistant cotton SGK321 has been widely adopted for many years in several regions of China, however the understanding of its potential effects on soil microorganisms is limited. The impact of transgenic cotton SGK321 on microorganism populations in rhizosphere soil was investigated. The numbers of bacteria, fungi, and actinomycetes were measured by counting colony-forming units after incubation on appropriate medium in a two-year field study in the northern China. Rhizosphere soil microorganism populations between transgenic cotton SGK321 and its non-transgenic parental cotton or conventional cotton were different at some plant growth stages and/or in some years. However compared to the plant growth stage and cotton cultivar, the impacts of the transgenic trait were slight or transient. The principal component analysis also showed no significant or minor difference in the numbers of bacteria, fungi, and actinomycetes in rhizosphere soil between transgenic cotton SGK321 and its non-transgenic parental cotton. These results suggest that the transgenic cotton SGK321 has no apparent impact on microorganism populations in rhizosphere soil.

Transgenic traits in the cotton crop in Brazil: a review

“…Sarkar et al (2008) evaluated the soil microbial activity, and found a significant reduction in dehydrogenase activity (17%) and soil respiration (3.5%) in a Bt-cotton rhizosphere compared with a non-Bt isoline. These results differ from those obtained by Li et al (2011), Velmourougane andSahu (2014), andZhang et al (2014), where transgenic cotton had no impact on microbial populations. According to Romeis et al (2006), the Bt technology is more specific and provides fewer environmental damages and collateral effects on parasitoids and predators than most insecticides currently used, which justifies its adoption due to the significant reduction in the number of applications.…”

“…Prado et al (2014) conducted an extensive review on the development of transgenic plants and described several phases involved from the initial concept to the release of the commercial product. The whole process may be summarized in consecutive procedures as follows: product concept (1), gene discovery (2), evaluation (3), event selection (4), variety development (5), regulatory process (6), field production (7), and commercial release (8). These procedures are distributed in five main phases: gene discovery and identification, genetic transformation, early development, advanced development, and prelaunch and launch.…”

Assessing Impacts of Transgenic Plants on Soil Using Functional Indicators: Twenty Years of Research and Perspectives

“…The potato plant growth stage and field location affected the soil enzyme activities more than the starch modification of tubers [100]. Compared to harvest year, plant growth stage and cotton cultivar, the pest resistance trait had a negligible effect on the activities of DHA, urease and phosphatase in soil [67]. The year and stage of growth significantly affected the urease, DHA and sucrase activities in the field trials of virus-resistant wheat [82].…”

O cultivo de milho transgênico Bt e seus impactos na microbiota do solo

“…Esses resultados podem, inicialmente, indicar que o tempo de condução experimental (103 dias) foi insuficiente para que evidenciasse o efeito da transgenia do milho Bt nos demais tratamentos relacionados ou não a FMAs, já que a mesma está relacionada, em condições de campo, à resistência a pragas, doenças e maior produção (Bobrowski et al, 2003). No entanto, em estudos anteriores, que conduziram experimentos também em curto prazo, avaliando o efeito de plantas geneticamente modificadas na microbiota do solo, não observaram alterações em atributos como densidade de bactérias, fungos e actinobactérias em solo rizosférico de algodão (Zhang et al, 2014), assim como Saxena & Stotzky (2001) que não observaram efeitos do milho Bt (Cry1Ab) na densidade total de microrganismos do solo, por um período de 40 dias.…”