Transcriptional Regulatory Crosstalk Between Heat Stress and Nitrogen–Sulfur Nutrition in Plants

Plant responses to high temperature depend on the nutritional state in which the stress occurs. Nitrogen and sulfur shape this state through photosynthetic capacity, protein synthesis, nitric oxide production, and thiol redox buffering, while heat alters nutrient uptake and assimilation. We review how nitrate and sulfate nutrition interact with heat responses through direct transcriptional cross-regulation, metabolite- or redox-mediated regulation, and convergence on shared processes. Nitrate provides the clearest transcriptional link: in Arabidopsis, the nitrate-responsive transcription factor NLP7 regulates HSFA2 and HSFA3, encoding heat stress transcription factors that sustain chaperone expression and acquired thermotolerance, and rice NLP3 binds the HsfA3 and HsfA7 promoters under heat. Nitrate reductase-derived nitric oxide modulates HSF activity, and warm temperature represses the nitrate transporter and sensor NRT1.1 through the transcription factor HY5. For sulfur, evidence comes mainly from glutathione-deficient mutants, glutathione application and hydrogen sulfide donors, which alter heat-responsive transcription factors and antioxidant genes; whether sulfate supply acts through these routes, and how sulfate sensing and the sulfate-limitation regulator SLIM1 contribute, remain unresolved. Comparing published Arabidopsis transcriptomic meta-analyses, we identify genes responding to heat and to nitrate or sulfate and propose candidate regulators. In crops, nitrogen maintains photosynthesis under heat but does not consistently protect yield.