This report summarizes the potential of phosphite (Phi) fertilization to boost soybean resilience under environmental stresses while serving as an alternative phosphorus (P) source. The study addressed four main goals: (1) assessing transcriptional responses to Phi in ptxD and wild-type (WT) soybean plants, (2) identifying Phi-induced metabolic changes, (3) evaluating Phi’s effects on nitrogen fixation and nodule formation, and (4) determining Phi’s role in resilience to heat and drought. We found that phosphite fertilization activates key defense genes across both genotypes, especially those linked to jasmonic acid biosynthesis and photosynthesis, thereby enhancing transcriptional stress responses. Metabolomic analysis showed that phosphite treatment significantly upregulates osmoregulatory and antioxidant metabolites, suggesting Phi acts as a priming agent that prepares plants to respond to abiotic stresses. In addition, we found that phosphite does not interfere with nitrogen-fixing bacteria, allowing successful nodule formation and maintaining the essential symbiotic relationships critical for nitrogen fixation and soil health. Under drought and heat, phosphite-treated plants exhibited improved growth, stable chlorophyll levels, and increased antioxidant activity, demonstrating enhanced resilience. In ptxD-transgenic plants, these effects were observed mainly under high phosphite concentrations that support the multiple effects. These findings highlight phosphite’s dual role as a phosphorus source and a stress tolerance enhancer, offering promising applications in sustainable agriculture. By improving stress resilience while supporting nitrogen fixation, phosphite fertilization in combination with ptxD transgenic plants can contribute to yield stability for soybean under climate-related stresses. These insights underline phosphite’s potential as a versatile tool in crop management; it helps control diverse weeds, including herbicide-resistant biotypes, provides phosphorus fertilization, and improves plant stress resilience. Studies under field settings are strongly recommended to confirm these benefits under diverse agricultural conditions and optimize phosphite application to maximize crop productivity and resilience.

This study provides an effective alternative agricultural system for soybean cultivation based on phosphite fertilization and ptxD plants. We demonstrated this system represents a valuable strategy to enhance phosphorus nutrition, control diverse weeds, and bolster soybean resilience to high temperature and water-limiting conditions.