Response to Salinity Stress in Plants and nitrogen effect: About hormone signaling pathway and root development

Around the world, 110 billion hectares of cultivated land in more than 100 countries are affected by soil salinity due to rapid climate change. Salinity and drought stress among various abiotic stresses are the main causes of significant decrease in crop production worldwide. In the 21st century, there are also predictions that 50% of the arable land will be affected by soil salinity. To alleviate the salt stress of crops and further increase production, mechanisms related to various physiological phenomena related to plant salt stress should be identified at the molecular level. In addition, plants can not move, so in order to successfully grow and develop in a given environment, various nutrients including micronutrients such as iron, manganese, and zinc are needed as well as large nutrients such as nitrogen, phosphorus and potassium. Most of these soil nutrients are absorbed into the plant body through the underground root system of a wide range of plants. In particular, nitrogen is one of the essential macronutrients for plant growth and crop productivity. Plants evolved various mechanisms to adapt to unbalanced nitrogen conditions. However, plants absorb nitrates with the help of nitrogen-fixing-related bacteria around their roots, as they cannot absorb nitrogen directly from the atmosphere. To meet the growing demand for food resources, the large amount of synthetic nitrogen fertilizer supplied to crops increased dramatically as synthetic nitrogen fertilizers began to be developed, resulting in a significant increase in crop yields. However, most of the nitrates deposited in the soil are not absorbed by plants but spread to the surrounding environment, leading to serious environmental and ecological pollution. Thus, identification of regulatory genes associated with in-depth understanding of nitrate absorption, assimilation and their use mechanisms is a key prerequisite for improving nitrogen use efficiency (NUE) in crops, and consequently is critical for maintaining agricultural stability.