New Molecular Approaches to Improving Salt Tolerance in Crop Plants (original) (raw)
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Transgenic approaches to enhance salt and drought tolerance in plants
Plant Gene, 2017
Abiotic stresses including drought, salinity, extreme temperatures, and heavy metal stress, are responsible for reduction in crop yields around the globe. The situation may further worsen with the reduction in arable land in countries of Asia due to population explosion. Though the conventional breeding programs developed stress tolerant varieties, the pace was very slow due to complication in abiotic stress by complex multigene traits and cumbersome phenotyping procedures. With the dawn of plant biotechnology, enormous efforts have been made to engineer stress tolerance in major-crops and model-plants. A substantial number of stress-responsive and/or stress-regulated genes have been identified. Addressing these constraints would help us in better understanding how transgenic plants are tolerating drought and salinity. Overview of the present and future methodologies would enable us to gain more insights in understanding transgenic approaches for tolerance to abiotic stress.
Molecular basis of salt stress tolerance in crop plants
Pure and Applied Biology, 2015
Plant growth, survival, biomass production and yield are sensitive to abiotic stress factors. Salt stress is major problem for crop plant growth and yield and thus, salinity regard as a main limiting factor in crop productivity. Modern molecular biology tools if we use it explicate salt stress tolerance mechanism and then specific stress related gene expression is used to generate stress tolerant crops. Identification of genes that play important role in salt tolerance in plants when exposed to high salt levels in soil is very important tool to improve plant tolerance in stress condition. In a high salt concentration expression the genes represent salt tolerance mechanism and that information helpful to recover the plant growth under high salt. In high salt concentration, expressions of many genes encoding proteins increase and improve crop plant growth and productivity. In this review, we sum up the work which has been formerly reported about molecular basis of stress tolerance mechanism of crop plants under high salt levels.
Plant Molecular Responses to Salt Stress
2020
Plants are frequenly exposed to environmental changes. In fact, abiotic stresses are the most serious factors limiting the productivity of agricultural crops, with adverse effects on germination, plant vigor and crop quality and yield. In particular, salinity stress is a global problem widespread that affects over 800 million ha. In the Mediterranean area, seawater intrusion into freshwater aquifers highly contribute to soil salinisation, resulting in crops productivity decrease. Responses to abiotic stresses are complicated pathways involving the interaction of different signalling molecules to coordinate a specific metabolic pathways. The regulation of these responses involves transcriptional factors, which regulate gene expression by binding to specific DNA promoter sequences. Transcription factors involved in salt stress responses include DRE-related binding factors, leucine zipper DNA binding proteins, putative zinc finger proteins, myb proteins, bZIP/HD-ZIPs, and AP2/EREBP. Particularly, AP2/ERF domain proteins include the DREB or CBF proteins binding to dehydration response elements (DRE) or C-repeats. Transcription factors are powerful targets for genetic engineering in abiotic stress resistance in crops and many studies have been focused on this topic.
Molecular Mechanisms of Salt Tolerance in Plants Article ID: 41060
Salinity is a significant stressor that hinders the growth and productivity of plants in many parts of the world, resulting from the increasing use of low-quality irrigation water and soil salinization. To develop salt-tolerant plant varieties for these affected areas, it is essential to have a comprehensive understanding of how plants respond to salinity stress at various levels and to integrate molecular tools with physiological and biochemical techniques. Plant adaptation or tolerance to salinity stress involves a complex interplay of physiological traits, metabolic pathways, and gene networks. Recent research has identified various adaptive responses to salinity stress at the molecular, cellular, metabolic, and physiological levels. However, the mechanisms underlying salinity tolerance are still not fully understood.
What molecular mechanism is adapted by plants during salt stress tolerance
2010
Salt stress harmfully shocks agricultural yield throughout the world affecting production whether it is for subsistence or economic outcomes. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyper-osmolarity and ion disequilibrium. Salt tolerance and yield stability are complex genetic traits that are difficult to establish in crops since salt stress may occur as a catastrophic episode, be imposed continuously or intermittently and become gradually more severe at any stage during development. Molecular biology research has provided new insight into the plant response to salinity and identified genetic determinants that effect salt tolerance. Recent confirmation that many salt tolerance determinants are ubiquitous in plants has led to the use of genetic models, like Arabidopsis thaliana, to further dissect the plant salt stress response. Since many of the most fundamental salt tolerance determinants are those that mediate cellular ion homeostasis, this review will focus primarily on the functional essentiality of ion homeostasis mechanisms in plant salt tolerance. The transport systems that facilitate cellular capacity to utilize Na + for osmotic adjustment and growth and the role of the Salt-Overly-Sensitive (SOS) signal transduction pathway in the regulation of ion homeostasis and salt tolerance will be particularly emphasized. The objective of the review is to know "What molecular mechanism is adopted by plants during salt stress tolerance?" A conclusion will be presented that integrates cellular based stress signaling and ion homeostasis mechanisms into a functional paradigm for whole plants and defines biotechnology strategies for enhancing salt tolerance of crops.
Developing salt tolerant plants in a new century: A molecular biology approach
2003
Soil salinity is a major abiotic stress in plant agriculture strongly, influencing plant productivity world-wide. Classical breeding for salt tolerance in crop plants has been attempted to improve field performance without success. Therefore, an alternative strategy is to generate salt tolerant plants through genetic engineering. Several species and experimental approaches have been used in order to identify those genes that are important for salt tolerance. Due to high level of salt tolerance, halophytes are good candidates to identify salt tolerance genes. However, other species such as yeast and glycophytes have also been employed. Three approaches are commonly used to identify genes important for salt tolerance. The first approach is to identify genes involved in processes known to be critical for salt tolerance (osmolyte synthesis, ion homeostasis, etc.). The second approach is to identify genes whose expression is regulated by salt stress. This is relatively simply and applicable to any plant species. Genetic amenability of some species allows the third approach, which consists in the identification of salt tolerance determinants based on functionality. At the moment, there is a large number of reports in the literature claiming that plants with increased salt tolerance have been obtained. The main problem is that different plant species, stage of development, organs, promoters and salt conditions used it is difficult to compare the degree of salt tolerance conferred by different genes. In this review, we discuss progress made towards understanding the molecular elements involved in salt stress responses that have been used in transgenic approaches to improve salt tolerance.
Planta, 2003
Abiotic stresses, such as drought, salinity, extreme temperatures, chemical toxicity and oxidative stress are serious threats to agriculture and the natural status of the environment. Increased salinization of arable land is expected to have devastating global effects, resulting in 30% land loss within the next 25 years, and up to 50% by the year 2050. Therefore, breeding for drought and salinity stress tolerance in crop plants (for food supply) and in forest trees (a central component of the global ecosystem) should be given high research priority in plant biotechnology programs. Molecular control mechanisms for abiotic stress tolerance are based on the activation and regulation of specific stressrelated genes. These genes are involved in the whole sequence of stress responses, such as signaling, transcriptional control, protection of membranes and proteins, and free-radical and toxic-compound scavenging. Recently, research into the molecular mechanisms of stress responses has started to bear fruit and, in parallel, genetic modification of stress tolerance has also shown promising results that may ultimately apply to agriculturally and ecologically important plants. The present review summarizes the recent advances in elucidating stress-response mechanisms and their biotechnological applications. Emphasis is placed on transgenic plants that have been engineered based on different stressresponse mechanisms. The review examines the following aspects: regulatory controls, metabolite engineering, ion transport, antioxidants and detoxification, late embryogenesis abundant (LEA) and heat-shock proteins.