Molecular Approaches to Nutrient Uptake and Cellular Homeostasis in Plants Under Abiotic Stress

Abstract

Plants suffer from abiotic stress due to several soil- and environment-related factors. They need water and essential plant nutrients to carry out their metabolism and survive. Plant genome regulates expression of different sets of genes to ensure availability of nutrients and water under conditions of stress and maintain their cellular homeostasis. The plasma membranes of root hair cells have several channels, which contain transporter proteins, coded by their specific genes for uptake of water and each of the essential plant nutrients. The transporter proteins involved in water uptake are known as aquaporins (AQPs). Since plants encounter several water stress conditions during its growth period, plant genome has many AQP genes to maintain cellular water homeostasis. Two sets of genes regulate uptake of primary nutrients, nitrogen, phosphorus, and potassium. A set of high-affinity transporters are involved, when their concentration in the growth medium is low, and a set of low-affinity transporters at higher concentrations. There are specific transporters for uptake of secondary and micronutrients both under low- and high-nutrient stress conditions. Plant genome responds to various types of abiotic stresses such as cold, heat, salinity, drought, and oxidative stresses and regulates suitably uptake of nutrients to maintain their cellular homeostasis. Amino acids, plant growth regulators, intermediate metabolites, and the nutrients themselves are involved in induction or repression of transporter-encoding genes as well as posttranscriptional modification of transporter proteins. Transcription factors regulate expression of nutrient stress response genes and control nutrient homeostasis in plants at molecular level. miRNAs are involved in posttranscriptional regulation of gene expression and also in nutrient stress signal transduction pathways. Some of the beneficial elements such as Na and Si play significant roles in abiotic stress tolerance of plants. Heavy metals, which are toxic and have no known function in plant metabolism, are sometimes taken up by ion transporters involved in uptake of essential nutrients from mineral-rich soils. Plants take up radioactive isotopes without any apparent damage to them. Exposure to high nuclear radiations may kill some of the plants but others survive. Abiotic stress caused by climate change has its effect on nutrient uptake by plants.