Unlocking sugar subcellular dynamics: The crucial function and regulation of tonoplast sugar transporters in plant response to climate change

Tonoplast sugar transporters are key regulators of intracellular sugar partitioning, mediating sugar flux between the cytosol and vacuole—an essential process for plant development and stress adaptation. Recent advances have deepened our understanding of well-characterized transporters such as TSTs and SWEETs, while also expanding the transporter repertoire with newly identified members including SWEET2, ERDL4, and SFP1/SAST1 across diverse plant species, including crops. Despite these insights, the regulatory mechanisms controlling transporter activity remain largely unresolved. This review aims to consolidate this expanding body of knowledge and explore in greater depth the molecular regulatory mechanisms controlling tonoplast sugar transporters. Additionally, we also analyze publicly available expression datasets to evaluate the potential of these transporters as targets for improving plant resilience under climate change conditions, particularly in response to elevated atmospheric CO₂. Ultimately, this review presents a new perspective on the significance of studying tonoplast sugar transporters, aiming to develop innovative strategies that enhance plant resilience to environmental challenges.