Effects of Field-Grown Transgenic Cry1Ah1 Poplar on the Rhizosphere Microbiome

Abstract

Background: Poplar (Populus) is a genus of globally important plantation trees used widely in industrial and agricultural production. However, poplar is easily damaged by Micromelalopha troglodyta and Hyphantria cunea, resulting in a decline in poplar quality. Due to their strong insect resistance, Bt toxin-encoded Cry genes have been widely adopted in poplar breeding; however, potential adverse effects of Cry1Ah1-modified poplars on the ecological environment have raised concerns. Results: In this study, we comprehensively analyzed the structural and functional composition of the rhizosphere microbiome in field-grown transgenic Bt poplar. Conclusions: Our analysis of soil chemistry patterns revealed that soil alkaline nitrogen, soil available phosphorus, and microbial biomass nitrogen and phosphorus levels were improved, whereas microbial biomass carbon declined in Cry1Ah1-modified poplar rhizosphere samples. We applied metagenomic sequencing of Non-Transgenic (NT) and Cry1Ah1-modified poplar rhizosphere samples collected from a natural field; the predominant taxa included Proteobacteria, Acidobacteria, and Actinobacteria. We also identified microbial functional traits involved in membrane transport, amino acid metabolism, carbohydrate metabolism, and replication and repair in NT and Cry1Ah1-modified poplars. Together, these results demonstrate that the NT and Cry1Ah1-modified poplar rhizosphere microbiomes had similar diversity and structure. These differences in relative abundance were observed in a few genera but did not affect the primary genera or soil.

Genetically Modified Sugarcane Intercropping Soybean Impact on Rhizosphere Bacterial Communities and Co-occurrence Patterns

“…These microbes are associated with numerous important biochemical reactions that affect plant growth and metabolism ( Souza et al, 2015 ). The integration of transgenic plants may have either intended or unintended effects on soil microbial communities and functions ( DeBruyn et al, 2017 ; Wei et al, 2020 ). The interaction between genetically modified (GM) crops and rhizosphere microbes is mainly associated with the production of root exudates and tiller or leaf degradation ( Khan et al, 2017 ).…”

Combinatorial transient gene expression strategies to enhance terpenoid production in plants

“…Some of the frequently employed techniques include overexpression of rate-limiting enzymes, often including 1-deoxy-D-xylulose 5-phosphate synthase (DXS), 1-deoxy-D-xylulose-5phosphate reductoisomerase (DXR), and 3-hydroxy-3methylglutaryl-CoA reductase (HMGR), reconstruction of the synthetic MVA pathway in Escherichia coli and overexpression of a transcription factor to increase the overall flux (Paddon et al, 2013;Lv et al, 2016). The rate-limiting enzyme of MEP (DXS and DXR) and MVA (HMGR) activity is highly regulated and considered in the upstream biosynthetic pathway for the synthesis of diverse functional metabolites (Wei et al, 2019). Typically, the overexpression of these important genes is enough to double the concentration of target compounds.…”