Adaptation mechanisms of low-phosphorus stress in plants: physiological responses, molecular regulation, and future perspectives

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Phosphorus (P) is essential for plant growth and development. Although soils contain abundant total P, about 70% of global arable land is deficient in available inorganic phosphate (Pi), severely restricting sustainable agricultural production. To date, numerous physiological and molecular mechanisms underlying plant adaptation to low-Pi stress have been elucidated. In this review, we provide an overview of recent advances in plant adaptation to low-Pi stress at both the physiological and molecular levels, including root plasticity and hormonal regulation, root exudate-mediated Pi acquisition, metabolic adaptation such as sugar metabolism, membrane lipid remodeling, and secondary metabolite accumulation, as well as arbuscular mycorrhizal (AM) symbiosis. Furthermore, we summarize the molecular regulatory networks governing plant responses to low-Pi stress, covering phosphate transporters, SPX-PHR signaling, transcription factors, non-coding RNAs, and epigenetic modifications. The interaction between low-Pi signaling and other signaling pathways is also discussed. This review synthesizes recent advances in adaptive mechanisms across multiple regulatory levels and discusses strategies for breeding P-efficient crops to support sustainable agriculture.