Functional roles of osmotin, dehydrin and aquaporin in drought stress response: comparative analysis in tomato and olive

Climate change is exacerbating the frequency and severity of droughts, thereby inducing substantial stress in crops. This review investigates the molecular responses to water deficit in two key Mediterranean crops: the annual tomato (Solanum lycopersicum) and the perennial olive (Olea europaea). The focus is on the function of osmotin, dehydrin (DHN) and aquaporin (AQP) proteins, which are essential for drought stress tolerance. Osmotin protects enzymes and functions as a chaperone, DHNs mitigate oxidative stress and enhance water retention, and AQPs control water transport. A comparative analysis of tomato and olive demonstrates contrasting adaptive mechanisms. Tomato, an annual plant, increases AQP expression to promote photosynthesis, despite increased water loss, and quickly completes its life cycle. Olive, a perennial species, exhibits a more complex AQP modulation, decreasing expression during stress and increasing it during recovery for water conservation. Olive trees also accumulate DHNs as a defense against dehydration. These molecular differences in osmotin, DHN and AQP responses highlight the distinct adaptive strategies of annual and perennial species. This review offers insights into drought tolerance mechanisms in crops, potentially aiding the development of climate-resilient varieties.