My research explores the intricate roles of ion transport, γ-aminobutyric acid (GABA), and calcium (Ca²⁺) signalling in plant stress physiology. I have focused on elucidating key mechanisms underlying plant-environment interactions using extensive range of techniques, covering molecular biology, cell biology, electrophysiology and plant physiology. My research has led to groundbreaking discoveries in three key areas:

• GABA signalling in plants: I definitively proved the non-protein amino acid GABA as a bona fide signalling molecule in plants, acting via a mechanism not found in animals. My work discovered the first plant ‘GABA receptors’ and demonstrated its role in reducing stomatal opening –small pores surround by guard cells on leaf surface control transpirational water loss, which improves water use efficiency in plants (Ramesh et al., 2015; Xu et al., 2021a, 2021b). Additionally, my research also revealed GABA’s impact on guard-cell Reactive Oxygen Species (ROS) signalling but not stomatal carbon dioxide (CO₂) sensing, shedding the light on its complex interaction with other plant signals (Xu et al., 2024; Piechatzek et al., 2024).
• Salinity tolerance in plants: I uncovered natural variation in wheat’s salinity tolerance through different sodium (Na⁺) exclusion capacities by root Na⁺ transporters, and identified key amino-acid residues within these transporters that influence wheat tolerance to salt. My findings led to the development of wheat cultivars with improved salinity tolerance, now being utilized in breeding programs worldwide (Munns et al., 2012; Byrt et al., 2014; Xu et al., 2018, 2020).
• Calcium nutrient and signalling: I discovered a novel calcium (Ca²⁺) sensor that modulates plant cell-to-cell communication and disease resistance, linking it to calcium nutrient storage and signalling pathways facilitated by two Ca²⁺ transporters, which is essential for optimal plant growth (Xu et al., 2017; Hocking et al., 2017).

My current research focus on refining cell-specific GABA signalling and membrane ion transport to develop innovative strategies for enhancing water-use efficiency and carbon gain in crops, particularly under hot and dry climates, with direct relevance to the fields of molecular biology and biotechnology.