biostudies-literatureXu HNational Key Research, Development Program of ChinaJoint Research Program of State Key Laboratory of Agricultural and Forestry BiosecurityFunding for a World-Class Plant Protection DisciplineNatural Science Foundation of FujianNational Natural Science Foundation of China -Youth Fund ProjectNational Natural Science Foundation-Outstanding Youth Foundatione11907https://www.ebi.ac.uk/biostudies/studies/S-EPMC12948193biostudies-literatureUnknown13(12)Enhancing nitrogen-use efficiency is essential for boosting crop yields and advancing sustainable agriculture, particularly in the absence of synthetic fertilizers. Despite the inherent nitrogen-fixation capacity of the staple legume crop soybean (Glycine max) by symbiotic rhizobia, improving nitrogen use has been challenging. Here, a role for the auxin-efflux transporters PIN3a and PIN3b in soybean nitrate acquisition is uncovered. PIN3a/b localizes to the plasma membrane, and high environmental nitrate induces PIN3a degradation and its accumulation at cell junctions. Disrupting PIN3 homologs results in auxin over-accumulation, impairs pavement-cell polarity, and enhances signaling via the transcription factors ARF and STF3/4. These transcription factors separately bind to and activate thAdvanced science (Weinheim, Baden-Wurttemberg, Germany)Soybean Auxin Transporter PIN3 Regulates Nitrate Acquisition to Improve Nitrogen Use and Seed Traits.PMC12948193SKLJPR25052022YFA09121002023J0148232300277322220092022J01161133-725025010BWu KHan QChen JHuang LXu HWang JShi XWang MLiu YHuang STu TChen ZZhang YWang TLin GGao ZChen XfalseSoybean Auxin Transporter PIN3 Regulates Nitrate Acquisition to Improve Nitrogen Use and Seed Traits.Enhancing nitrogen-use efficiency is essential for boosting crop yields and advancing sustainable agriculture, particularly in the absence of synthetic fertilizers. Despite the inherent nitrogen-fixation capacity of the staple legume crop soybean (Glycine max) by symbiotic rhizobia, improving nitrogen use has been challenging. Here, a role for the auxin-efflux transporters PIN3a and PIN3b in soybean nitrate acquisition is uncovered. PIN3a/b localizes to the plasma membrane, and high environmental nitrate induces PIN3a degradation and its accumulation at cell junctions. Disrupting PIN3 homologs results in auxin over-accumulation, impairs pavement-cell polarity, and enhances signaling via the transcription factors ARF and STF3/4. These transcription factors separately bind to and activate th2026-01-01T00:00:00Z2026 Feb2026-07-16T22:28:57.216Z2026-07-11T03:12:08.503ZS-EPMC129481934125091310.1002/advs.202511907