scholarly journals Salinity Stress: Toward Sustainable Plant Strategies and Using Plant Growth-Promoting Rhizobacteria Encapsulation for Reducing It

2021 ◽  
Vol 13 (22) ◽  
pp. 12758
Author(s):  
Roohallah Saberi Riseh ◽  
Marzieh Ebrahimi-Zarandi ◽  
Elahe Tamanadar ◽  
Mojde Moradi Pour ◽  
Vijay Kumar Thakur

Salinity is one of the most important abiotic stresses that influences plant growth and productivity worldwide. Salinity affects plant growth by ionic toxicity, osmotic stress, hormonal imbalance, nutrient mobilization reduction, and reactive oxygen species (ROS). To survive in saline soils, plants have developed various physiological and biochemical strategies such as ion exchange, activation of antioxidant enzymes, and hormonal stimulation. In addition to plant adaption mechanisms, plant growth-promoting rhizobacteria (PGPR) can enhance salt tolerance in plants via ion homeostasis, production of antioxidants, ACC deaminase, phytohormones, extracellular polymeric substance (EPS), volatile organic compounds, accumulation of osmolytes, activation of plant antioxidative enzymes, and improvement of nutrients uptake. One of the important issues in microbial biotechnology is establishing a link between the beneficial strains screened in the laboratory with industry and the consumer. Therefore, in the development of biocontrol agents, it is necessary to study the optimization of conditions for mass reproduction and the selection of a suitable carrier for their final formulation. Toward sustainable agriculture, the use of appropriate formulations of bacterial agents as high-performance biofertilizers, including microbial biocapsules, is necessary to improve salt tolerance and crop productivity.

2009 ◽  
Vol 55 (11) ◽  
pp. 1302-1309 ◽  
Author(s):  
Sajid Mahmood Nadeem ◽  
Zahir Ahmad Zahir ◽  
Muhammad Naveed ◽  
Muhammad Arshad

Salt stress is one of the major constraints hampering agricultural production owing to its impact on ethylene production and nutritional imbalance. A check on the accelerated ethylene production in plants could be helpful in minimizing the negative effect of salt stress on plant growth and development. Four Pseudomonas , 1 Flavobacterium , and 1 Enterobacter strain of plant growth promoting rhizobacteria containing 1-aminocyclopropane-1-carboxylate (ACC)-deaminase were selected and their effects on growth and yield of maize were investigated to improve the salt tolerance of maize grown on salt-affected fields. The selected rhizobacterial isolates reduced or eliminated the classical “triple” response, indicating their ability to reduce stress-induced ethylene levels. Results showed that rhizobacterial strains, particularly Pseudomonas and Enterobacter spp., significantly promoted the growth and yield of maize compared with the non-inoculated control. Pseudomonas fluorescens increased plant height, biomass, cob yield, grain yield, 1000 grain mass, and straw yield of maize up to 29%, 127%, 67%, 60%, 17%, and 166%, respectively, over the control. Under stress conditions, more N, P, and K uptake and high K+–Na+ ratios were recorded in inoculated plants compared with the control. The results imply that inoculation with plant growth promoting rhizobacteria containing ACC-deaminase could be a useful approach for improving growth and yield of maize under salt-stressed conditions.


2011 ◽  
Vol 57 (7) ◽  
pp. 578-589 ◽  
Author(s):  
Maqshoof Ahmad ◽  
Zahir A. Zahir ◽  
H. Naeem Asghar ◽  
M. Asghar

Twenty-five strains of plant-growth-promoting rhizobacteria (PGPR) containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase and 10 strains of rhizobia were isolated from rhizosphere soil samples and nodules of mung bean. They were screened in separate trials under salt-stressed axenic conditions. The three most effective strains of PGPR (Mk1, Pseudomonas syringae ; Mk20, Pseudomonas fluorescens ; and Mk25, Pseudomonas fluorescens biotype G) and Rhizobium phaseoli strains M1, M6, and M9 were evaluated in coinoculation for their growth-promoting activity at three salinity levels (original, 4 dS·m–1, and 6 dS·m–1) under axenic conditions. The results showed that salinity stress significantly reduced plant growth but inoculation with PGPR containing ACC deaminase and rhizobia enhanced plant growth, thus reducing the inhibitory effect of salinity. However, their combined application was more effective under saline conditions, and the combination Mk20 × M6 was the most efficient for improving seedling growth and nodulation. The effect of high ethylene concentrations on plant growth and the performance of these strains for reducing the negative impact of saline stress was also evaluated by conducting a classical triple-response bioassay. The intensity of the classical triple response decreased owing to inoculation with these strains, with the root and shoot lengths of inoculated mung bean seedlings increasing and stem diameter decreasing, which is a typical response to the dilution in a classical triple response bioassay. Thus, coinoculation with PGPR containing ACC deaminase and Rhizobium spp. could be a useful approach for inducing salt tolerance and thus improving growth and nodulation in mung bean under salt-affected conditions.


2013 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Umesh P. Shrivastava ◽  
Ashok Kumar

A total of nine strains of plant growth promoting rhizobacteria were analyzed for ACC deaminase activity, where highest ACC deaminase activity was found in Klebsiella sp strain ECI-10A (539.1 nmol α-keto butyrate/ mg protein/ h) and lowest in Microbacterium sp strain ECI-12A (122.0 nmol α-keto butyrate/ mg protein/ h). Although Microbacterium sp strain ECI-12A showed lowest level of ACC deaminase activity, but, the species of Microbacterium isolated from rhizosphere is the first report. Microbacterium sp strain ECI-12A was also analyzed under varying conditions of time, amount of 1-Aminocyclopropane-1- carboxylate (ACC), and temperature for optimization of the ACC deaminase activity. The optimum activity was recorded with the supplementation of 5mM ACC at 30°C temperature after 24h of culture growth. All the nine strains showed acdS gene in the PCR amplification of that gene. No any rhizospheric Microbacterium species showing ACC deaminase activity have been reported earlier, therefore, we report here ACC deaminase activity in Microbacterium sp ECI-12A isolated from rice rhizosphere is a novel finding. DOI: http://dx.doi.org/10.3126/ijasbt.v1i1.7921 Int J Appl Sci Biotechnol, 2013, Vol. 1(1): 11-15


2021 ◽  
Vol 21 (no 1) ◽  
Author(s):  
Z. Mary Swaroopa ◽  
R. Jaya Madhuri

Crop productivity and crop improvement are colloidal components as the demand of the increasing population, worldwide for the provision of food from crops require dedicated agricultural strategies that tend to lean on natural, available and, beneficial, easily reproducible means of products. In general, the soil components rich in organic matter that can avail rich microbial community initiates agricultural productivity in abundance and in the way to deduce it. But, commercially available chemical pesticides, pollution in the environment, biotic and abiotic constituents are found to be the key components that stress the crop productivity. This can be overtaken by the microbes that can function as both “bio-fertilizer” and “antagonistic” agents, mentioned as Plant growth-promoting rhizobacteria(PGPR), as they present satisfactory, advantageous impact when ever required, due to their presence in the rhizospheric region, by providing nutrients uptake from soil and controlling the unnecessary hazardous bio-impact on plants .Present study relies on sustainable agricultural development that utilizes the bacteria from the rhizospheric region thereby recommending bio-formulation in the future to mobilize the unaware farmer for better productivity, free of devastating chemical components that enter the food chain via crop produced by using chemicals, and also by easy means without affecting the surrounding environment and human health. In this context, Sclerotium rolfsii, a deleterious pathogen that affects groundnut crops predominantly, how best can be prevented and can be suppressed by using beneficial PGPR is been studied.


2021 ◽  
Vol 12 ◽  
Author(s):  
Pu-Sheng Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Yu Zhang

Salt stress is one of the major abiotic stresses that affects plant growth and development. The use of plant growth-promoting rhizobacteria to mitigcate salt stress damage in plants is an important way to promote crop growth under salt stress conditions. Rahnella aquatilis JZ-GX1 is a plant growth-promoting rhizobacterial strain, but it is not clear whether it can improve the salt tolerance of plants, and in particular, the role of volatile substances in plant salt tolerance is unknown. We investigated the effects of volatile organic compounds (VOCs) from JZ-GX1 on the growth performance, osmotic substances, ionic balance and antioxidant enzyme activities of acacia seedlings treated with 0 and 100mm NaCl and explored the VOCs associated with the JZ-GX1 strain. The results showed that compared to untreated seedlings, seedlings exposed to plant growth-promoting rhizobacterium JZ-GX1 via direct contact with plant roots under salt stress conditions exhibited increases in fresh weight, lateral root number and primary root length equal to approximately 155.1, 95.4, and 71.3%, respectively. Robinia pseudoacacia seedlings exposed to VOCs of the JZ-GX1 strain showed increases in biomass, soil and plant analyser development values and lateral root numbers equal to 132.1, 101.6, and 166.7%, respectively. Additionally, decreases in malondialdehyde, superoxide anion (O2−) and hydrogen peroxide (H2O2) contents and increases in proline contents and superoxide dismutase, peroxidase and glutathione reductase activities were observed in acacia leaves. Importantly, the sodium-potassium ratios in the roots, stems, and leaves of acacia exposed to VOCs of the JZ-GX1 strain were significantly lower than those in the control samples, and this change in ion homeostasis was consistent with the upregulated expression of the (Na+, K+)/H+ reverse cotransporter RpNHX1 in plant roots. Through GC-MS and creatine chromatography, we also found that 2,3-butanediol in the volatile gases of the JZ-GX1 strain was one of the important signaling substances for improving the salt tolerance of plants. The results showed that R. aquatilis JZ-GX1 can promote the growth and yield of R. pseudoacacia under normal and salt stress conditions. JZ-GX1 VOCs have good potential as protectants for improving the salt tolerance of plants, opening a window of opportunity for their application in salinized soils.


2019 ◽  
Vol 10 ◽  
Author(s):  
Dilfuza Egamberdieva ◽  
Stephan Wirth ◽  
Sonoko Dorothea Bellingrath-Kimura ◽  
Jitendra Mishra ◽  
Naveen K. Arora

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