Salt tolerance in rice: Physiological responses and molecular mechanisms

Crop yield loss due to soil salinization is an increasing threat to agriculture worldwide. Salt stress drastically affects the growth, development, and grain productivity of rice (Oryza sativa L.), and the improvement of rice tolerance to salt stress is a desirable approach for meeting increasing food demand. The main contributors to salt toxicity at a global scale are Na' and Cl ions, which affect up to 50% of irrigated soils. Plant responses to salt stress occur at the organismic, cellular, and molecular levels and are pleiotropic, involving (1) maintenance of ionic homeostasis, (2) osmotic adjustment, (3) ROS scavenging, and (4) nutritional balance. In this review, we discuss recent research progress on these four aspects of plant physiological response, with particular attention to hormonal and gene expression regulation and salt tolerance signaling pathways in rice. The information summarized here will be useful for accelerating the breeding of salt-tolerant rice. (C) 2021 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

Soil salinization-induced crop yield loss is a growing threat to global agriculture. The growth, development, and grain productivity of rice are significantly affected by salt stress, and enhancing rice tolerance to salt stress is crucial for meeting the increasing food demand. The main contributors to salt toxicity on a global scale are Na+ and Cl- ions, which affect up to 50% of irrigated soils. Plant responses to salt stress occur at various levels and involve maintaining ion balance, osmotic adjustment, scavenging reactive oxygen species (ROS), and maintaining nutritional balance. This review summarizes recent research progress on these four aspects of plant physiological response, with a focus on hormonal and gene expression regulation, as well as salt tolerance signaling pathways in rice. The information presented here will be valuable for accelerating the breeding of salt-tolerant rice.