Evolution and stress-responsive regulation of the apyrase gene family in Chinese cabbage (Brassica rapa L. ssp. pekinensis): a genome-wide perspective on temperature and drought tolerance.

Apyrases (APYs), nucleoside triphosphate-diphosphohydrolases, serve as critical enzymes in regulating extracellular ATP levels and maintaining biochemical homeostasis under stress conditions. Under the escalating pressures of global climate change, the adverse effects of rising temperatures and altered precipitation patterns on crop productivity have become increasingly severe. Chinese cabbage (Brassica rapa L. ssp. pekinensis, B.rapa), a globally significant cruciferous crop, faces substantial threats due to its high sensitivity to environmental stressors. Throughout its growth cycle, it is frequently subjected to various environmental stresses and exhibits high sensitivity to drought stress and temperature fluctuations. In this study, we systematically identified 13 APY genes in the B.rapa genome and conducted a comprehensive analysis of their phylogenetic relationships, conserved motifs, and cis-regulatory elements. qRT-PCR analysis further revealed distinct tissue-specific expression patterns of BrAPYs and their differential regulation under drought, extreme temperature, and cold stress conditions. These findings establish a molecular framework for understanding the stress-responsive functions of APYs in Chinese cabbage and highlight potential targets for enhancing stress tolerance through genetic improvement.