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

We investigated the 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 both field and controlled conditions.

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 morpho-physiological and molecular level were studied under different N and P treatment combinations.

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 principal component analysis (PCA; PC1 + PC2) accounted for 54.1% (low N) and 56.1% (low P) genetic variability. Among genotypes, the traits like biomass, N and P uptake, root morphology, N assimilation, and 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.

Differential gene expression in wheat, particularly in HD2781, enhanced nutrient uptake, assimilation, and internal nutrient reutilization, contributing to dual-nutrient stress tolerance. Recognizing resilient genotypes like HD2781 is crucial for sustaining wheat productivity in low-fertility soils.