Stylosanthes guianensis (stylo), an important tropical and subtropical green manure crop, shows remarkable adaptation to acidic soils with low phosphate (Pi) availability. Nevertheless, the specific mechanisms underlying its high phosphorus (P) utilization efficiency (PUE) in acidic soils are not fully understood. This study combined a field experiment conducted in low-Pi acidic soils with multifaceted analyses to compare the physiological and molecular responses of two stylo genotypes differing in PUE. The high-PUE genotype P457 was superior to the low-PUE genotype Reyan No.2 in acidic soils, exhibiting significantly greater biomass, P content, and PUE. Notably, P457 displayed higher leaf acid phosphatase (APase) activity than Reyan No.2. Untargeted metabolomic and lipidomic analyses further revealed significantly lower phospholipid levels in P457 leaves than in Reyan No.2. Transcriptomic analysis identified significantly elevated expression of a purple APase gene ( SgPAP10b ) in P457 leaves than in those of Reyan No.2. Functional characterization of SgPAP10b via heterologous overexpression in Arabidopsis demonstrated that it not only enhanced shoot biomass, PUE, and APase activity but also reduced shoot phospholipid levels relative to wild-type plants. Recombinant SgPAP10b exhibited phosphatase activity and high hydrolytic activity toward phospholipids, including phosphatidylethanolamine and lysophosphatidylcholine. Taken together, our results suggest that SgPAP10b -mediated lipid remodeling and P recycling are associated with the superior low-Pi adaptability of P457, thereby contributing to improved PUE. These findings uncover a previously unrecognized role of SgPAP10b in stylo adaptation to low-Pi conditions and highlight it as a promising target for enhancing PUE in crops grown on acidic soils. • Genotype P457 achieves high PUE via high APase activity and low phospholipid levels • SgPAP10b is essential for phospholipid degradation to enhance PUE • P457 and SgPAP10b are key resources for breeding cultivars targeting low-P acid soils
Xu et al. (Sun,) studied this question.