Plants have continuously to cope with changing environmental conditions. In this context, soil salinization is a major environmental challenge reducing the yield of crops, which are mostly salt sensitive species. Soil salinization primarily depends on geological processes, such as those involving rock erosion and inland sea water intrusion. Evolving climate conditions exacerbated this process by promoting drought and desertification. In this situation, adaptive strategies emerge increasing biodiversity. Therefore, the identification of intra-species variability in terms of molecular responses activated toward oncoming adverse situations, represents a research goal aimed at increasing crop resilience under climate change scenario.
Baldo (B) and Vialone Nano (VN), two rice cultivars grown in the North of Italy, have been identified for showing different susceptibility to soil salinization. In particular, VN plants showed more marked growth reduction and earlier suffering symptoms than B ones under NaCl exposure.
Being root the organ primarily involved in sensing this stress, the effects of salt stress on root phenotype and metabolism have been investigated. Different root growth inhibition was reflected in different alteration of cell cycle progression and cellular viability. Upon perception of stress, ROS, as molecular warning signals, were rapidly modulated to trigger plant defence mechanisms. The higher capability to face a constraint condition by plants also involves a more efficient anti-oxidative system and a higher capacity to promptly modulate ROS after stress exposure. Consistently, the salt tolerant B shows a different H2O2 signature compared to VN. Studies on root redox state, metabolite concentrations, expression and activity of the enzymes involved in glutathione biosynthesis and metabolism as well as the modulation of miRNA involved in S uptake and metabolism suggest a fine cross-talk between GSH metabolic network and the modulation of growth pathways differently exerted in tolerant versus sensitive cultivars.
Taken together the obtained results contribute to highlight the role of ROS and anti-oxidative pathways as a part of a complex signalling network working in plant responses against salt stress. A better knowledge of the mechanisms acting in tolerant varieties as B, will also allow the identification of effective strategies aimed at promoting crop resilience toward environmental stress and, consequently, increasing food availability for humans worldwide.
Audience Take Away:
- The identification of molecular and genetic determinants of plant tolerance to salt is a complex matter, being salt exposure a multifaceted stress for plants.
- 2 The study of intra-species variability can help to identify breeding and biotechnological strategies to increase crop resilience to salt.