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 maize, rice and wheat constitute major crop groups and serve as essential nutritional sources for a large portion of the global population. These crops hold significant international importance and, as central components of human diets, play a decisive role in ensuring global food security. Moreover, particularly in arid and semi-arid regions, cereals are recognized as primary providers of carbohydrates and proteins. The production of these staple crops faces numerous challenges: abiotic stresses such as drought, salinity, heat and cold can substantially reduce their yield and performance. Among these factors, salt stress stands out as one of the major barriers to cereal crop production. The key question addressed here is: How can cereals perceive environmental stimuli and, via intricate regulatory networks, activate their defense pathways to cope with such stresses?
Research findings
The plant (including cereal) response to salt stress typically unfolds in two distinct phases: initially, osmotic stress; subsequently, ionic toxicity followed by secondary stresses such as oxidative stress and nutritional imbalances. At the physiological level, plants confront salt stress by utilizing efficient systems for ion uptake and distribution, maintaining osmotic balance and accumulating protective compounds. At the biochemical level, activation of antioxidant systems and synthesis of compatible solutes such as proline—are among the principal strategies to mitigate oxidative damage triggered by salinity. On the molecular level, complex networks of transcription factors and functional genes (for example, NHX1, HKT1, SOS and P5CS) coordinate the salt‐stress response. Key signaling pathways including the MAPK cascade and the SOS (Salt-Overly Sensitive) pathway play central roles in transducing the stress signal and initiating defense responses. The identification of quantitative trait loci (QTLs) associated with salt tolerance and candidate genes has advanced our understanding of the genetic basis of this trait. Since salt tolerance is a quantitative (polygenic) trait controlled by multiple genes, its molecular processes are regulated via extensive regulatory networks comprising transcription factors and functional genes. Pathways such as MAPK and SOS have been widely studied in cereals, and the present findings draw on research specific to those crops; for example, in rice the SOS1, SOS2 and SOS3 genes enhance salt tolerance by mediating sodium efflux from the cytosol, thereby preventing ionic toxicity. Additionally, the accumulation of protective compounds (e.g., proline) and activation of antioxidant defenses are critically involved in maintaining cellular integrity under saline conditions.
Conclusion
Considering the polygenic nature of salt tolerance, it is imperative to conduct genetic studies and identify relevant QTLs and key genes. Ultimately, the integration of physiological, genetic and molecular findings into breeding programmers coupled with the use of genomic approaches is indispensable for the development of novel cereal varieties that are salt-tolerant and exhibit stable performance under saline conditions.
کلیدواژهها [English]
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