نوع مقاله : مقاله مروری
نویسندگان
1 استادیار پژوهش، مرکز ملی تحقیقات شوری، سازمان تحقیقات، آموزش و ترویج کشاورزی، یزد، ایران
2 دانشیار، گروه زراعت و اصلاح نباتات، دانشکده کشاورزی، دانشگاه یاسوج، یاسوج، ایران
3 استاد، گروه تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شیراز، شیراز، ایران
4 دانشیار پژوهش، مرکز ملی تحقیقات شوری، سازمان تحقیقات، آموزش و ترویج کشاورزی، یزد، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Cereals such as wheat, rice, and maize, rank among the most important agricultural products on a global scale. As fundamental components of the human diet, these crops play a decisive role in ensuring food security for the world's population. The production of these crops particularly in arid and semi-arid regions faces numerous challenges, with abiotic stresses such as drought, salinity, heat, and cold capable of significantly reducing their yields. Among these factors, salinity stress is recognized as a major constraint on crop production. The key question is: how are cereals able to perceive environmental cues and activate their defense pathways through intricate regulatory networks to cope with such stress? The aim of the present study is to provide a comprehensive and up-to-date overview of recent advances in understanding the physiological and molecular mechanisms of salt tolerance in crop plants, with a special focus on cereals.
Research findings
In most plants, including cereals, salinity stress typically occurs in two distinct phases: first, osmotic stress, followed by ionic toxicity, leading to secondary stresses such as oxidative stress and nutritional imbalances. From a physiological perspective, plants cope with salinity stress by employing effective systems that regulate ion uptake and distribution, maintain osmotic balance, and accumulate protective compounds. At the biochemical level, the activation of antioxidant systems and the production of compatible solutes such as proline are key strategies for mitigating the oxidative stress induced by salinity. At the molecular level, complex networks of transcription factors and functional genes including NHX1, HKT1, SOS, and P5CS are responsible for coordinating the stress response. Key signaling pathways, such as the MAPK cascade and the SOS pathway, play a central role in transducing stress signals and activating defense responses. The identification of QTLs associated with salt tolerance and effective candidate genes has advanced our understanding of the genetic basis of salt tolerance in plants. Given that salt tolerance is a complex quantitative trait controlled by multiple genes, its molecular processes are coordinated through extensive regulatory networks comprising transcription factors and functional genes. The MAPK and SOS pathways have been extensively studied in cereals, and our understanding of salt tolerance is grounded in research specifically focused on these plants. For instance, the SOS1, SOS2, and SOS3 genes in rice enhance salt tolerance by facilitating sodium ion efflux from cells and preventing ionic toxicity. Furthermore, the accumulation of osmolytic compounds (including proline) and the activation of antioxidant systems play a crucial role in maintaining cellular integrity in plants under salinity stress.
Conclusion
Given the polygenic and complex nature of salt tolerance, conducting genetic studies to identify QTLs and effective genes is critically important. Furthermore, integrating physiological, genetic, and molecular mechanisms into breeding programs, along with leveraging genomic approaches, appears essential for developing new salt-tolerant and stable-yielding cereal varieties.
کلیدواژهها [English]
)