Induction of abiotic stress tolerance in plants by endophytic microbes (original) (raw)
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Role of Plant Endophytes in Conferring Abiotic Stress Tolerance
Plant Ecophysiology and Adaptation under Climate Change: Mechanisms and Perspectives II
Plants, being stationary, are continuously challenged to extreme environmental conditions like drought, salinity, heat, cold, etc. that limit crop productivity by about 50-70%. The response of plants to these abiotic stresses is complex and involves a plethora of physiological, biochemical, and gene expression changes. A number of approaches like plant breeding, genetic engineering, mutagenesis, and omics-based approaches have been used to understand and impart tolerance against various types of stresses in economically important plant species. This chapter would, however, focus on the application of endophytes (a group of beneficial microorganisms present within the plant tissues) in conferring selective advantage to host plants with which they are associated in harsh environmental conditions. Numerous reports have proposed that endophytes impart stress tolerance to plants either by activation of host stress response system or by biosynthesis of anti-stress metabolites like plant growth regulators, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, volatiles, bioactive compounds, etc. Depending on the types of abiotic stress, different types of endophytes adopt different signaling mechanisms which may include synthesis and accumulation of compatible solutes, adjustment in ion transport, expression of stress-responsive genes, generation of ROS scavenger
6 Role of Endophytes in Plant Health and Abiotic Stress Management
2019
Microbial endophytes are symbionts dwelling within plant tissues without appearance of disease symptoms on host plant and have been recently investigated for their plant growth-promoting properties and their beneficial functions associated with plant responses under abiotic stress conditions. This study focuses on the critical role of endophytic microbes in plant health and their stim-ulatory different mechanisms to tolerance against abiotic stress in plants. Endophytic microbial community can enhance plant growth through producing secondary active compounds which protect the plant from pathogens such as insect and fungi; also endophytes can produce extracellular enzymes which play critical roles in colonization of endophytes within the plant host. Microbial endo-phytes have the ability to act as plant growth-promoting agents through producing phytohormones and also enable plants to grow in contaminated soils through breakdown of hazardous compounds. Endophytes manage plant growth under adverse conditions such as salinity, drought, temperature, heavy metal stress, and nutrient stress through different mechanisms. This chapter may introduce new approaches for the use of endophytic inoculants to combat abiotic stresses in agricultural fields, which increases global crop production.
Journal of Ecophysiology and Occupational Health
Microbial communities in nature involve complex interactions with several biotic and abiotic components. An endo-symbiotic association is one in which one organism lives within the host plant for at least a part of its life. It is often obligate and does not create visible disease and has been reported to exist for at least 400 million years. Beneficial endophytes promote plant nutrient uptake, host plant growth, reduce disease severity, inhibit plant pathogens and improve tolerance to environmental stresses. Stresses like salinity, alkalinity, drought, global warming, temperature and pollution will increase in prominence and endophytes are predicted to play a significant role and offer eco-friendly techniques to increase productivity under such conditions. There also exists the potential for genetic modification of endophytes to impart additional stress tolerance traits in hosts. The present review discusses the beneficial effect of fungal and bacterial endophytes, emphasizing impr...
Endophytic Bacteria in Plant Salt Stress Tolerance: Current and Future Prospects
Journal of Plant Growth Regulation, 2018
Soil salinity is a major limiting factor for crop productivity worldwide and is continuously increasing owing to climate change. A wide range of studies and practices have been performed to induce salt tolerance mechanisms in plants, but their result in crop improvement has been limited due to lack of time and money. In the current scenario, there is increasing attention towards habitat-imposed plant stress tolerance driven by plant-associated microbes, either rhizospheric and/or endophytic. These microbes play a key role in protecting plants against various environmental stresses. Therefore, the use of plant growth-promoting microbes in agriculture is a low-cost and eco-friendly technology to enhance crop productivity in saline areas. In the present review, the authors describe the functionality of endophytic bacteria and their modes of action to enhance salinity tolerance in plants, with special reference to osmotic and ionic stress management. There is concrete evidence that endophytic bacteria serve host functions, such as improving osmolytes, anti-oxidant and phytohormonal signaling and enhancing plant nutrient uptake efficiency. More research on endophytes has enabled us to gain insights into the mechanism of colonization and their interactions with plants. With this information in mind, the authors tried to solve the following questions: (1) how do benign endophytes ameliorate salt stress in plants? (2) What type of physiological changes incur in plants under salt stress conditions? And (3), what type of determinants produced by endophytes will be helpful in plant growth promotion under salt stress?
Frontiers in Microbiology, 2022
Change in global climate has started to show its effect in the form of extremes of temperatures and water scarcity which is bound to impact adversely the global food security in near future. In the current review we discuss the impact of drought on plants and highlight the ability of endophytes, microbes that inhabit the plants asymptomatically, to confer stress tolerance to their host. For this we first describe the symbiotic association between plant and the endophytes and then focus on the molecular and physiological strategies/mechanisms adopted by these endophytes to confer stress tolerance. These include root alteration, osmotic adjustment, ROS scavenging, detoxification, production of phytohormones, and promoting plant growth under adverse conditions. The review further elaborates on how omics-based techniques have advanced our understanding of molecular basis of endophyte mediated drought tolerance of host plant. Detailed analysis of whole genome sequences of endophytes followed by comparative genomics facilitates in identification of genes involved in endophyte-host interaction while functional genomics further unveils the microbial targets that can be exploited for enhancing the stress tolerance of the host. Thus, an amalgamation of endophytes with other sustainable agricultural practices seems to be an appeasing approach to produce climate-resilient crops.
The Use of Beneficial Microbial Endophytes for Plant Biomass and Stress Tolerance Improvement
Recent Patents on Biotechnology, 2010
Endophytes are microorganisms that live within host plants for at least part of their life and do not cause apparent symptoms of diseases. In general, beneficial endophytes promote host plant growth, increase plant nutrient uptake, inhibit plant pathogen growth, reduce disease severity, and enhance tolerance to environmental stresses. As sustainable and renewable agricultural production (including current biofuel and bioenergy crops) increases in prominence, endophytic microorganisms will play important roles and offer environmentally-friendly methods to increase productivity while reducing chemical inputs. This review discusses various aspects of beneficial fungal and bacterial endophyte interactions with plants, including the physiological and molecular mechansims by which they benefit plant performance. We also discuss the potential for genetic modification of endophytes with useful genes, which could be used to impart additional traits following inoculation with the genetically engineered endophytes. Finally, we review US-issued patents over the past decade which relate to the use of fungal and bacterial endophytes for plant growth and stress tolerance improvement.
Plant-Endophyte Interaction during Biotic Stress Management
Plants
Plants interact with diverse microbial communities and share complex relationships with each other. The intimate association between microbes and their host mutually benefit each other and provide stability against various biotic and abiotic stresses to plants. Endophytes are heterogeneous groups of microbes that live inside the host tissue without showing any apparent sign of infection. However, their functional attributes such as nutrient acquisition, phytohormone modulation, synthesis of bioactive compounds, and antioxidant enzymes of endophytes are similar to the other rhizospheric microorganisms. Nevertheless, their higher colonization efficacy and stability against abiotic stress make them superior to other microorganisms. In recent studies, the potential role of endophytes in bioprospecting has been broadly reported. However, the molecular aspect of host–endophyte interactions is still unclear. In this study, we have briefly discussed the endophyte biology, colonization effic...
Drought tolerance improvement in plants: an endophytic bacterial approach
Applied Microbiology and Biotechnology, 2019
Climate change is a crucial issue among the serious emerging problems which got a global attention in the last few decades. With the climate change, worldwide crop production has been seriously affected by drought stress. In this regard, various technologies including traditional breeding and genetic engineering are used to cope with drought stress. However, the interactions between plants and endophytic bacteria emerged as an interesting era of knowledge that can be used for novel agriculture practices. Endophytic bacteria which survive within plant tissues are among the most appropriate technologies improving plant growth and yield under drought conditions. These endophytic bacteria live within plant tissues and release various phytochemicals that assist plant to withstand in harsh environmental conditions, i.e., drought stress. Their plant growth-promoting characteristics include nitrogen fixation, phosphate solubilization, mineral uptake, and the production of siderophore, 1-aminocyclopropane-1carboxylate (ACC) deaminase, and various phytohormones. These plant growth promoting characteristics of endophytic bacteria improve root length and density, which lead to the enhance drought tolerance. In addition, plant-endophytic bacteria assist plant to withstand against drought stress by producing drought-tolerant substances, for instance, abscisic acid, indole-3-acetic acid, ACC deaminase, and various volatile compounds. Indirectly, endophytic bacteria also improve osmotic adjustment, relative water content, and antioxidant activity of inoculated plants. Altogether, these bacterial-mediated drought tolerance and plant growth-promoting processes continue even under severe drought conditions which lead to enhanced plant growth promotion and yield. The present review highlights a natural and environment-friendly strategy in the form of drought-tolerant and plant growth-promoting endophytic bacteria to improve drought tolerance in plants.
Role of microbes in alleviating abiotic stress in plants
Plant Science Today
The leading threat to agricultural productivity is the recurrent variations in environmental conditions. A battery of abiotic stresses namely flooding, salinity, temperature, drought, heavy metal toxicities, nutrient deficiencies and oxidative stress causes irreversible damage resulting in loss of plant’s vigor and yield. The relationship between plants and microorganisms is a highly dynamic system. The plant microbiome consists of plant growth-promoting bacteria and fungi. In the last decade, many microbes that give hosts the ability to withstand abiotic stress have been characterized in detail. Their beneficial association with plants enables the plant to endure different stresses imposed on them thereby enhancing the plant's sustainability and productivity. For sustainable agriculture, it is very significant to comprehend microbiome-assisted mechanisms for mitigating abiotic stress. This review will shed light on the current knowledge about the roles of various microorganisms...
Cells
Biotic and abiotic stresses severely affect agriculture by affecting crop productivity, soil fertility, and health. These stresses may have significant financial repercussions, necessitating a practical, cost-effective, and ecologically friendly approach to lessen their negative impacts on plants. Several agrochemicals, such as fertilizers, pesticides, and insecticides, are used to improve plant health and protection; however, these chemical supplements have serious implications for human health. Plants being sessile cannot move or escape to avoid stress. Therefore, they have evolved to develop highly beneficial interactions with endophytes. The targeted use of beneficial plant endophytes and their role in combating biotic and abiotic stresses are gaining attention. Therefore, it is important to experimentally validate these interactions and determine how they affect plant fitness. This review highlights research that sheds light on how endophytes help plants tolerate biotic and abi...