From swamp to field: how genes from mangroves and its associates can enhance crop salinity tolerance

Salinity stress is a critical challenge in crop production and requires innovative strategies to enhance the salt tolerance of plants. Insights from mangrove species, which are renowned for their adaptability to high-salinity environments, provides valuable genetic targets and resources for improving crops. A significant hurdle in salinity stress is the excessive uptake of sodium ions (Na⁺) by plant roots, causing disruptions in cellular balance, nutrient deficiencies, and hampered growth. Specific ion transporters and channels play crucial roles in maintaining a low Na⁺/K⁺ ratio in root cells which is pivotal for salt tolerance. The family of high-affinity potassium transporters, recently characterized in Avicennia officinalis, contributes to K⁺ homeostasis in transgenic Arabidopsis plants even under high-salt conditions. The salt overly sensitive pathway and genes related to vacuolar-type H⁺-ATPases hold promise for expelling cytosolic Na⁺ and sequestering Na⁺ in transgenic plants, respectively. Aquaporins contribute to mangroves' adaptation to saline environments by regulating water uptake, transpiration, and osmotic balance. Antioxidant enzymes mitigate oxidative damage, whereas genes regulating osmolytes, such as glycine betaine and proline, provide osmoprotection. Mangroves exhibit increased expression of stress-responsive transcription factors such as MYB, NAC, and CBFs under high salinity. Moreover, genes involved in various metabolic pathways, including jasmonate synthesis, triterpenoid production, and protein stability under salt stress, have been identified. This review highlights the potential of mangrove genes to enhance salt tolerance of crops. Further research is imperative to fully comprehend and apply these genes to crop breeding to improve salinity resilience.