Changes in the Stress Response and Fitness of Hybrids Between Transgenic Soybean and Wild-Type Plants Under Heat Stress

Understanding the ability of hybrids of genetically modified (GM) soybean and wild soybean to survive and reproduce under unfavorable conditions is critical for answering questions regarding risk assessment and the existence of transgenes in the environment. To investigate the effects of high-temperature stress on soybean growth and competitive ability, the GM soybean DBN8002, which expresses the VIP3Aa and PAT proteins, and F generations derived from a cross between GM soybean and NJW (wild soybean) were placed in a greenhouse with an elevated temperature (38/32 °C) for 14 days, and the plant agronomic performance and foreign protein levels of hybrid soybean were evaluated to observe their responses to high temperature. The results revealed that the VIP3Aa and PAT protein levels in F and GM were not influenced by high-temperature stress. In contrast, the pollen germination, pod number, hundred-seed weight, and seed vigor of the F hybrid and parent soybean plants decreased after high-temperature stress. However, except for the number of fully filled seeds per plant, the above parameters of the F hybrid were similar to or slightly lower than those of wild soybean, and no significant difference in fitness was observed between the F hybrid and wild soybean, indicating that the growth and competitive ability of the hybrid were similar to those of its female parent under heat stress conditions, resulting in the transgenes persisting and spreading within agricultural ecosystems. Our results enhance the understanding of the GM soybean plant's response to heat stress, lay the foundation for breeding heat-resistant soybean varieties, and provide new insights and advanced information on the ecological risks arising from the escape of transgenes.