Assessment of environmental microbial effects of insect-resistant transgenic Populus × euramericana cv. ‘74/76’ based on high-throughput sequencing

Abstract

Pests and diseases present major obstacles to poplar growth, which have been overcome via transgenic engineering applications. However, given the long growth cycle of transgenic poplars, long-term environmental safety assessments are needed for transgenic poplars planted in the field. Therefore, we investigated the effects of exogenous genes in transgenic poplar on the diversity of endophytic and rhizosphere soil bacterial communities in poplars. The composition and diversity of bacterial communities in trunk tissue, root tissue, and rhizosphere soil samples of transgenic Populus × euramericana cv. ‘74/76’ containing the high-resistance gene HPb1 (hereafter, HPb1) and non-transgenic Populus × euramericana cv. ‘74/76’ (hereafter, 107) in a 4-year-old experimental forest were analyzed using high-throughput sequencing. In terms of bacterial abundance at the phylum level, in trunk tissue, Bacteroidetes was the dominant phylum in both poplar lines (HPb1: 32.17%; 107: 47.42%). In root tissue, Proteobacteria was the dominant phylum in both lines (HPb1: 67.52%; 107: 65.96%). In rhizosphere soil, Proteobacteria was the dominant phylum in both lines (HPb1: 39.75%; 107: 37.98%). There were no significant differences in the richness and diversity of bacterial communities between HPb1 and 107. Finally, the bacterial community compositions in root tissue and rhizosphere soil were highly similar, both of which differed somewhat from that in trunk samples. This study provides a reference for ecological safety assessments of transgenic poplars and allows for a more systematic understanding of the potential ecosystem risk posed by environmental release of transgenic poplars.