Assessment of soil bacterial diversity in long-term cultivation of virus-resistant GM papaya

Concerns over the environmental impact of genetically modified (GM) plants include potential horizontal gene transfer (HGT) of antibiotic-resistant genes used for constructing GM plants, leading to changes in soil bacterial diversity. A landfill pond with virus-resistant GM papaya, along with soil from greenhouse continuously growing GM papaya for over 10 years, were used to assess the long-term effects of GM papaya on soil bacterial diversity. Therefore, we aimed to investigate the impact of GM plant materials on soil bacterial diversity.

Pre-planting soil and soil growing GM and wild-type papaya were analyzed along with soil from landfill ponds with or without GM papaya. The abundance of NPTII sequence matching the selectable marker gene sequence of the recombinant plasmid used to engineer GM papaya was assessed via high-throughput sequencing, while microbial diversity was evaluated through metagenomic analysis of 16S rRNA.

No change was detected in the abundance of NPTII sequence due to GM papaya. Moreover, there was no distinct separation among soil samples, except those from the control pond with no GM plant material, which exhibited lower Firmicute abundance and higher Proteobacteria abundance. However, the difference is likely unrelated to GM papaya.

This study found no changes in the overall soil bacterial diversity or NPTII sequences in the bacterial population due to the presence of virus-resistant GM papaya even after more than a decade of continuous presence.