Chapter 22 - Abiotic-stress tolerance in plants-system biology approach

Abstract

Abiotic stresses of the environment, such as soil salinity, drought, extreme temperatures (heat and cold), light, water supply, nutrient deficiency, excess levels of metals within the soil, negatively impact plant growth. Agriculture faces intolerable economic losses wherever stress-related alterations in plant development, growth, and productivity ultimately results in limited yield. Soil salinity and water scarcity (drought) problems exist in India, Argentina, China, the United States, Sudan, and many other countries in Western and Central Asia. Field crop estimation showed that almost all crops give best result only reaching 30% of the genetic potential for yield, but over 90% of global rural land area is considered affected globally by abiotic stresses during the growing season. Most common responses to abiotic stresses in plants include differential transcription of the many genes; production of stress-responsive genes leading to cellular metabolic changes; alteration in activity behavior of many enzymes; overproduction of several compatible metabolites such as amino acids, sugars, polyamines, phytochelatins, organic acids; increased synthesis of many enzymes and stress-specific proteins. These specific responses to stresses have served as basis to engineer crop plants suitable for cultivation in the stress-prone regions of the world. Generally, plants are affected by low and moderate levels of abiotic stresses, but when the intensity of stress increases, tolerance mechanism of plants start breaking down that might ultimately result into death of the plant. To satisfy the increasing demand of food of the developing and underdeveloped nations where abiotic stresses are severe constraints to crop productivity, development of stress-tolerant plants appear to be a propitious approach. Several biochemical, physiological, and metabolic strategies are developed in plants to combat such abiotic stresses. Often it is hard to foresee the complex signaling pathway that are activated or deactivated in response to various abiotic stresses. New biotechnological methods should be adopted by plant breeders to accelerate breeding program. Specifically, breeders must emphasize on increasing the tolerance of crops to abiotic stresses. Development of crop species with increasing yield below stress environment can be possible by the use of modern genetic engineering tools which help in selection across multiple traits and reduce cost and time. It is a big challenge to current agriculture biotechnology to fulfill increasing demand in food production due to constant increase in world population which may achieve 9 billion by 2050. Responses of crop plants in a systems biology manner will be helpful to build networks or models that will give better understanding of varied responses of crop plants to a dynamic environment which empowering us to outline the best engineering strategy for the development of enhanced abiotic-stress tolerant crop species. Systems biology is an imminent field in the area of plant science going for coordinating information from various high throughput “omics” platforms, for example, transcriptome, metabolome, proteome, and genomics to comprehend the regulatory structure and association of plant responses and their inherent components. They give new bits of knowledge and open new horizons for the better understanding of stresses and responses and also the improvement of plant responses and its resistance to stresses. Because of the vast-scale nature of these approaches, bioinformatics and computational approaches are highly connected with the above for either developing new data analytical methods, better visualization, or storage in sustainable online resources. Omic technologies have been used in substantial researches as a way to identify imperative intermediates controlling stress tolerance and as a tool to screen for variation in plants. The outcomes obtained by utilizing these approaches would then be able to be delivered using genetic transformation.