Halophytes and Climate Change: Elucidation of Salt-Tolerance Mechanisms and Biodiversity Conservation

The progressive secondary salinisation of irrigated farmland, mostly caused by accumulation in the soil of toxic ions dissolved in the irrigation water and accelerated by climate change, is a major contributor to declining crop yields. The best approach to address this problem should be the genetic improvement of crop salt tolerance, which requires a deep understanding of the underlying molecular mechanisms of tolerance. Over the last two decades, halophytes, plants adapted to natural saline environments, have emerged as ideal models to elucidate these mechanisms. In this chapter, we summarise some examples of studies conducted on a wide variety of halophytes, which provide valuable insights into stress tolerance mechanisms, from anatomical adaptations and physiological and biochemical responses to molecular approaches, including gene isolation and characterisation and “omics” technologies. Furthermore, the effects of climate change on natural saline habitats are also mentioned, highlighting concerns about biodiversity loss, local extinction of sensitive species, and the proliferation of invasive species under evolving climatic conditions. Knowledge of tolerance levels and mechanisms becomes essential for designing and implementing effective conservation and regeneration programmes. The final section includes a more personal view on halophyte research, based on our group’s work over the last 20 years, with some comments and recommendations to pursue work with this amazing group of salt-tolerant plants.