scholarly journals Mitigating abiotic stress in crop plants by microorganisms

Author(s):  
Nada Milosevic ◽  
Jelena Marinkovic ◽  
Branislava Tintor

Microorganisms could play an important role in adaptation strategies and increase of tolerance to abiotic stresses in agricultural plants. Plant-growth-promoting rhizobacteria (PGPR) mitigate most effectively the impact of abiotic stresses (drought, low temperature, salinity, metal toxicity, and high temperatures) on plants through the production of exopolysaccharates and biofilm formation. PGPR mitigate the impact of drought on plants through a process so-called induced systemic tolerance (IST), which includes: a) bacterial production of cytokinins, b) production of antioxidants and c) degradation of the ethylene precursor ACC by bacterial ACC deaminase. Symbiotic fungi (arbuscular mycorrhizal fungi) and dual symbiotic systems (endophytic rhizospheric bacteria and symbiotic fungi) also tend to mitigate the abiotic stress in plants.

2021 ◽  
Vol 9 (7) ◽  
pp. 1491
Author(s):  
Alka Sagar ◽  
Parikshita Rathore ◽  
Pramod W. Ramteke ◽  
Wusirika Ramakrishna ◽  
Munagala S. Reddy ◽  
...  

Soil saltiness is a noteworthy issue as it results in loss of profitability and development of agrarian harvests and decline in soil health. Microorganisms associated with plants contribute to their growth promotion and salinity tolerance by employing a multitude of macromolecules and pathways. Plant growth promoting rhizobacteria (PGPR) have an immediate impact on improving profitability based on higher crop yield. Some PGPR produce 1-aminocyclopropane-1-carboxylic (ACC) deaminase (EC 4.1.99.4), which controls ethylene production by diverting ACC into α-ketobutyrate and ammonia. ACC deaminase enhances germination rate and growth parameters of root and shoot in different harvests with and without salt stress. Arbuscular mycorrhizal fungi (AMF) show a symbiotic relationship with plants, which helps in efficient uptake of mineral nutrients and water by the plants and also provide protection to the plants against pathogens and various abiotic stresses. The dual inoculation of PGPR and AMF enhances nutrient uptake and productivity of several crops compared to a single inoculation in both normal and stressed environments. Positively interacting PGPR + AMF combination is an efficient and cost-effective recipe for improving plant tolerance against salinity stress, which can be an extremely useful approach for sustainable agriculture.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1531
Author(s):  
Narcisa Urgiles-Gómez ◽  
María Eugenia Avila-Salem ◽  
Paúl Loján ◽  
Max Encalada ◽  
Leslye Hurtado ◽  
...  

Coffee is an important, high-value crop because its roasted beans are used to produce popular beverages that are consumed worldwide. Coffee plantations exist in over 70 countries and constitute the main economic activity of approximately 125 million people. Currently, there is global concern regarding the excessive use of agrochemicals and pesticides in agriculture, including coffee crops. This situation has motivated researchers, administrators, and farmers to seek ecologically friendly alternatives to decrease the use of synthetic fertilizers and pesticides. In the last decades, multiple studies of the rhizosphere, at the chemical, physical and biological levels, have improved our understanding of the importance of beneficial microorganisms to plant health and growth. This review aims to summarize the state of the use of plant growth-promoting microorganisms (PGPM) in coffee production, where the most extensively studied microorganisms are beneficial plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF). This review also contains information on PGPM, in regard to plantations at different latitudes, isolation techniques, mass multiplication, formulation methods, and the application of PGPM in nurseries, monoculture, and coffee agroforestry systems. Finally, this review focuses on relevant research performed during the last decade that can help us improve sustainable coffee production.


2021 ◽  
Vol 3 ◽  
Author(s):  
Michael Prabhu Inbaraj

Crop plants are continuously exposed to various abiotic stresses like drought, salinity, ultraviolet radiation, low and high temperatures, flooding, metal toxicities, nutrient deficiencies which act as limiting factors that hampers plant growth and low agricultural productivity. Climate change and intensive agricultural practices has further aggravated the impact of abiotic stresses leading to a substantial crop loss worldwide. Crop plants have to get acclimatized to various environmental abiotic stress factors. Though genetic engineering is applied to improve plants tolerance to abiotic stresses, these are long-term strategies, and many countries have not accepted them worldwide. Therefore, use of microbes can be an economical and ecofriendly tool to avoid the shortcomings of other strategies. The microbial community in close proximity to the plant roots is so diverse in nature and can play an important role in mitigating the abiotic stresses. Plant-associated microorganisms, such as endophytes, arbuscular mycorrhizal fungi (AMF), and plant growth-promoting rhizobacteria (PGPR), are well-documented for their role in promoting crop productivity and providing stress tolerance. This mini review highlights and discusses the current knowledge on the role of various microbes and it's tolerance mechanisms which helps the crop plants to mitigate and tolerate varied abiotic stresses.


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 194 ◽  
Author(s):  
José Ramón Acosta-Motos ◽  
Consuelo Penella ◽  
José A. Hernández ◽  
Pedro Díaz-Vivancos ◽  
María Jesús Sánchez-Blanco ◽  
...  

Salinity is one of the main constraints for agriculture productivity worldwide. This important abiotic stress has worsened in the last 20 years due to the increase in water demands in arid and semi-arid areas. In this context, increasing tolerance of crop plants to salt stress is needed to guarantee future food supply to a growing population. This review compiles knowledge on the use of phytoprotectants of microbial origin (arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria), osmoprotectants, melatonin, phytohormones and antioxidant metabolism-related compounds as alleviators of salt stress in numerous plant species. Phytoprotectants are discussed in detail, including their nature, applicability, and role in the plant in terms of physiological and phenotype effects. As a result, increased crop yield and crop quality can be achieved, which in turn positively impact food security. Herein, efforts from academic and industrial sectors should focus on defining the treatment conditions and plant-phytoprotectant associations providing higher benefits.


2017 ◽  
Vol 5 (2) ◽  
pp. 196-199
Author(s):  
Amrit Kumar Jha

A field experiment was conducted on trace metal contaminated soil at Patratu (Ramgarh) to study the effect of lime, compost, plant growth promoting rhizobacteria and arbuscular mycorrhizal fungi on micronutrient removal viz. Zn, Cu, Mn and Fe in mustard-maize cropping system. Results reveal that inoculation with Glomus mossae, Pseudomonas striata and Azotobacter chroococcum increased Zn concentration to the extent 13 to 32, 10 to 24 and 9 to 24 (%), respectively over control. Copper, manganese and iron uptake followed almost similar trend as that of Zn. Microbial inoculants with or without vermicompost increased the trace metal removal, however, vermicompost alone decreased the removal. It was observed that microbial inoculations reduced the total Zn, Cu, Mn and Fe content in soil. However, available micronutrients were significantly reduced by microbial inoculation and amendments.


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