Dual-nutrient induced stress tolerance in wheat is regulated by nitrogen and phosphorus uptake, assimilation, reutilization, and differential expression of candidate genes

Abstract

Background and Aims We investigated genetic variability in wheat for dual-nutrient stress (DNS) tolerance in field conditions due to soil deficiencies in essential nutrients like nitrogen (N) and phosphorus (P). Most studies focus on model plants in controlled environments, but our research addresses DNS tolerance at the whole-plant level in real-world field conditions. Methods Seventy wheat genotypes were evaluated in field under low nutrient conditions (two years each for N and P). Data were subjected to principal component analysis and genotypes clustering by Ward’s method. In selected genotypes, the DNS tolerance mechanisms at physiological and molecular level were studied under different N and P treatment combinations. Results Field evaluation under low N and P demonstrated decreased total biomass and grain yield while nutrient use efficiency increased in comparison to their respective controls. The PCA (PC1+PC2) accounted for 54.1% (low N) and 56.1% (low P) genetic variability. Among genotypes, the physiological traits (biomass, N and P uptake, root morphology, N assimilation, extracellular acid phosphatase activity) were superior in HD2781, while inferior in C306 thereby, confirming the pattern obtained in the field. The expression of candidate genes involved in N and P transport, N assimilation, internal P remobilization, and transcription factors was significantly higher in HD2781 in comparison to C306. Conclusion Differential gene expression in wheat, particularly in genotype HD2781, enhances nutrient uptake, assimilation, and internal reutilization, contributing to dual-nutrient stress (DNS) tolerance. Recognizing resilient genotypes like HD2781 is crucial for sustaining wheat productivity in low-fertility soils.