Purple acid phosphatases (PAPs) play a key role in phosphorus (P) assimilation and redistribution in plants, catalyzing the hydrolysis of phosphate esters to produce inorganic phosphate (Pi). In this study, a total of 77 PAP genes were identified in B. napus. The candidate genes were divided into three groups and ten subgroups based on the phylogenetic analyses and exon-intron organization. Among these 77 BnaPAP proteins, 35 exhibit typical metal-ligating residues characteristic of known PAPs, whereas certain unaltered amino acid residues were absent or displaced in other BnaPAPs. A computational prediction was conducted, revealing that the majority of PAPs contain signal peptide motifs and display a range of N-glycosylation levels, as well as transmembrane helix motifs. An analysis of previously obtained RNA-seq data revealed that 55.84% (43 of 77) of the BnaPAPs responded to Pi deficiency. Moreover, we conducted a preliminary examination of the expression profiles of BnaPAP genes in response to salt stress, and discovered that 42.86% (33 of 77) of these genes were induced under salt stress, either in the shoots or in the roots. Further qRT-PCR and GUS analyses revealed that BnaC9.PAP10 and BnaA7.PAP10, two paralogs of BnaPAP10s, were induced by Pi deficiency. Notably, BnaC9.PAP10 exhibits robust induction, compared to the relatively mild induction observed in BnaA7.PAP10. Our research shows that BnaA7.PAP10 uniquely responds to Pi stress via the W-box, while BnaA7.PAP10 predominantly responds via the P1BS element, and the differences in cis-regulatory elements (CREs) within their promoter regions specifically contribute to their distinct expression levels under Pi stress. Our findings provide valuable insights and establish a foundation for future functional studies of BnaPAPs.

Wheat (Triticum aestivum L.) is considered one of the most important cereals globally, contributing significantly to the human population’s caloric and protein requirements. Therefore, ensuring a sufficient yield of wheat for global consumption plays a significant role in maintaining food security in different parts of the world. With increasing demand and dwindling production capacity, due to increasingly uncertain growing conditions, projections indicate that there should be an upswing of 60–70% in wheat productivity by 2050 to fulfill the requirement. However, drought represents the most significant and widespread abiotic limitation to global wheat production, currently resulting in approximately 10% yield losses worldwide. Furthermore, each additional 1 °C increase in temperature is anticipated to decrease staple calorie production by 4.4%. The factors contributing to drought in wheat, as well as its impact on the plant’s biochemical, physiological, and morphological structures, include altered rainfall patterns, elevated atmospheric CO₂ levels, increased temperatures, hot and dry winds, and restricted soil water availability. These factors initiate a series of morphological, physiological, and biochemical disruptions that hinder wheat growth and productivity. Drought impact on wheat starts at biochemical levels through reactive oxygen species (ROS) generation and degradation of chlorophylls, and tolerance to stress is influenced by a polygenic system where numerous genes contribute minor effects and interact significantly with environmental factors transitioning to osmoprotectants. At the physiological level, drought alters the water content in the plant body, leading to reduced net photosynthetic rates, stomatal conductance, transpiration rates, and water utilization efficiency. At the morphological level, drought impacts all kinds of structures such as roots, shoots, leaves and reproductive parts. To counter these effects, wheat develops a set of tolerant mechanisms called drought escape, avoidance and tolerance. An increase in trichomes and leaf waxes, alteration of root–shoot ratios, the staying green phenomenon, production of stress proteins like proline, activity of enzymes including superoxide dismutase (SOD), ascorbate peroxidase, catalase, etc., osmotic adjustment, abscisic acid (ABA) accumulation, expression of dehydration proteins called dehydrin, etc., contribute towards drought tolerance. This comprehensive review investigates the intricate interactions between drought and various wheat genotypes, emphasizing their substantial impacts on plant physiology, biochemistry, growth dynamics, and grain yield. Additionally, this review assesses a variety of genetic and biotechnological strategies aimed at enhancing the resilience of wheat genotypes to drought stress. By integrating recent research findings with practical applications, this review provides a detailed framework for improving the adaptive capacity of wheat plants to withstand the escalating threats of drought stress, thereby supporting sustainable wheat production in a changing climate. Addressing drought stress through genetic and biotechnological management practices is crucial for maintaining wheat productivity.