Research progress on the formation, function, and impact of calcium oxalate crystals in plants

Calcium oxalate (CaOx) crystals, ubiquitous in numerous plant families, have emerged as fascinating and complex structures with far-reaching implications in plant physiology, ecology, and human health. This paper encapsulates a comprehensive exploration of CaOx crystals, beginning with their formation and physiological role within plants, to their larger ecological implications, and finally, their impact on human society. Recent research has elucidated key genes involved in CaOx crystal formation, as well as the crystals' diverse physiological roles, including their function in calcium regulation, defense against herbivory, and potential contributions to carbon sequestration. We also highlight the ecological significance of CaOx crystals in nutrient cycling and plant-soil interactions, and the potential hazards posed by these crystals in human nutrition, particularly in the context of oxalate-rich diets and kidney stone formation. Despite significant advances, many aspects, particularly their ecological impacts and potential role in climate change mitigation, remain under-explored, necessitating future research.