Rhizobacteria containing ACC-deaminase confer salt tolerance in maize grown on salt-affected fields

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.

2019 ◽  
Vol 17 (1) ◽  
pp. e0801 ◽  
Author(s):  
Mitra Azadikhah ◽  
Fatemeh Jamali ◽  
Hamid-Reza Nooryazdan ◽  
Fereshteh Bayat

Plant growth-promoting rhizobacteria containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme reduce the level of stress, ethylene and stimulate plant growth under various biotic and abiotic stress conditions. The present study aims at characterizing efficient salt-tolerant, ACC deaminase containing Pseudomonas fluorescens strains with plant growth-promoting activity isolated from the rhizosphere of barley plants and evaluating the influence of potent plant growth-promoting rhizobacteria (PGPR) isolates on growth and yield of five barley cultivars under salinity stress. Plant growth and yield in barley cultivars following inoculation with salt-tolerant, ACC deaminase producing PGPR strains under salt stress were quantified. Results indicated that under various levels of salinity (50, 100 and 150 mM NaCl) inoculation with PGPRs had positive impact on growth parameters and yield of barley cultivars including plant height, spike length, weight and number, peduncle length, number of grains per spike, 1000-grain weight and grain yield, comparing to uninoculated control plants under salinity stress. Inoculation of barley cultivars with bacteria ameliorated the negative effects of salinity and resulted in increase in growth and yield. Besides, as the salinity levels increased, growth and yield of barley cultivars decreased; however, cultivars showed different responses to salt stress. This study demonstrates the vital role of rhizobacteria containing ACC deaminase for increasing salt tolerance and consequently improving the growth and yield of barley plants under salinity stress.


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.


2007 ◽  
Vol 53 (10) ◽  
pp. 1141-1149 ◽  
Author(s):  
Sajid Mahmood Nadeem ◽  
Zahir Ahmad Zahir ◽  
Muhammad Naveed ◽  
Muhammad Arshad

Twenty rhizobacterial strains containing 1-aminocyclopropane-1-carboxylate deaminase were isolated from the rhizosphere of salt-affected maize fields. They were screened for their growth-promoting activities under axenic conditions at 1, 4, 8, and 12 dS·m–1salinity levels. Based upon the data of the axenic study, the 6 most effective strains were selected to conduct pot trials in the wire house. Besides one original salinity level (1.6 dS·m–1), 3 other salinity levels (4, 8, and 12 dS·m–1) were maintained in pots and maize seeds inoculated with selected strains of plant growth-promoting rhizobacteria, as well as uninoculated controls were sown. Results showed that the increase in salinity level decreased the growth of maize seedlings. However, inoculation with rhizobacterial strains reduced this depression effect and improved the growth and yield at all the salinity levels tested. Selected strains significantly increased plant height, root length, total biomass, cob mass, and grain yield up to 82%, 93%, 51%, 40%, and 50%, respectively, over respective uninoculated controls at the electrical conductivity of 12 dS·m–1. Among various plant growth-promoting rhizobacterial strains, S5 ( Pseudomonas syringae ), S14 ( Enterobacter aerogenes ), and S20 ( Pseudomonas fluorescens ) were the most effective strains for promoting the growth and yield of maize, even at high salt stress. The relatively better salt tolerance of inoculated plants was associated with a high K+/Na+ratio as well as high relative water and chlorophyll and low proline contents.


HortScience ◽  
2013 ◽  
Vol 48 (5) ◽  
pp. 563-567 ◽  
Author(s):  
Huseyin Karlidag ◽  
Ertan Yildirim ◽  
Metin Turan ◽  
Mucahit Pehluvan ◽  
Figen Donmez

The effect of selected plant growth-promoting rhizobacteria (PGPR) on the growth, chlorophyll content, nutrient element content, and yield of strawberry plants under natural field salinity conditions stress was investigated. Field experiments were conducted using a randomized complete block design with five PGPRs (Bacillus subtilis EY2, Bacillus atrophaeus EY6, Bacillus spharicus GC subgroup B EY30, Staphylococcus kloosii EY37, and Kocuria erythromyxa EY43) and a control (no PGPR) in 2009 and 2010. PGPR inoculations significantly increased the growth, chlorophyll content, nutrient element content, and yield of strawberry plants. PGPR treatments lowered electrolyte leakage of plants under saline conditions. The leaf relative water content (LRWC) of plants rose with bacterial inoculation. All nutrient element contents of leaves and roots investigated were significantly increased with PGPR inoculations with the exception of sodium (Na) and chlorine (Cl). The highest efficiency to alleviate salinity stress on the yield and nutrient uptake of strawberry plants was obtained from EY43 (228 g per plant) and EY37 (225 g per plant) treatment and the yield increasing ratio of plants was 48% for EY43 and 46% for EY 37 compared with the control treatment (154 g per plant). The highest nitrogen (N), potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), manganese (Mn), copper (Cu), and iron (Fe) concentrations were obtained from EY43 and followed by E6, E37, and E30, and increasing ratio of leaves and root N, P, K, Ca, Mg, S, Mn, Cu, and Fe contents were 22% to 33%, 34% to 8.8%, 89% to 11%, 11.0% to 7.2%, 5.1% to 6.2%, 97% to 65%, 120% to 140%, 300% to 15%, and 111% to 9.0%, respectively. The results of the study suggested that PGPR inoculations could alleviate the deleterious effects of salt stress conditions on the growth and yield of strawberry plants under salinity conditions.


2020 ◽  
Vol 19 (6) ◽  
pp. 15-29
Author(s):  
Yagmur Yilmaz ◽  
Ceknas Erdinc ◽  
Ahmet Akkopru ◽  
Selma Kipcak

Salt stress affects many aspects of plant metabolism and as a result, growth and yield are reduced. The aim in this study was to determine the effects of plant growth promoting rhizobacteria (PGPR) on tomato plants under salt stress. With this aim, the Interland F1 cv. and bacterial isolates of Bacillus thuringiensis CA41/1, Pseudomonas putida 18/1K, Pseudomonas putida S5/4ep, and Pseudomonas putida 30 were used. Salt application was completed in two different doses of 25 and 50 mM NaCl when seedlings reached the stage of 3 true leaves. At the end of the study, in addition to seedling development criteria, some nutrient element contents and rates (K, Ca, Na, K/Na and Ca/Na), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) enzyme activities, malondialdehyde (MDA) and photosynthetic pigment contents were determined. In the stress environment, PGPR inoculation increased K content by up to 10%, while apart from isolate P. putida no.30, the other isolates lowered Na content by up to 18%. Additionally, 18/1K and S5/4ep isolates were identified to reduce membrane injury index by up to 97%. It was identified that CA41/1, 18/1K and S5/4ep isolates were more effective against salt stress, especially. In general, the plant tolerance levels induced by the bacteria were identified to increase with the increase in salt stress.


Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 712 ◽  
Author(s):  
Omena Ojuederie ◽  
Oluwaseyi Olanrewaju ◽  
Olubukola Babalola

Abiotic stresses arising from climate change negates crop growth and yield, leading to food insecurity. Drought causes oxidative stress on plants, arising from excessive production of reactive oxygen species (ROS) due to inadequate CO2, which disrupts the photosynthetic machinery of plants. The use of conventional methods for the development of drought-tolerant crops is time-consuming, and the full adoption of modern biotechnology for crop enhancement is still regarded with prudence. Plant growth-promoting rhizobacteria (PGPR) could be used as an inexpensive and environmentally friendly approach for enhancing crop growth under environmental stress. The various direct and indirect mechanisms used for plant growth enhancement by PGPR were discussed. Synthesis of 1-aminocyclopropane−1-carboxylate (ACC) deaminase enhances plant nutrient uptake by breaking down plant ACC, thereby preventing ethylene accumulation, and enable plants to tolerate water stress. The exopolysaccharides produced also improves the ability of the soil to withhold water. PGPR enhances osmolyte production, which is effective in reducing the detrimental effects of ROS. Multifaceted PGPRs are potential candidates for biofertilizer production to lessen the detrimental effects of drought stress on crops cultivated in arid regions. This review proffered ways of augmenting their efficacy as bio-inoculants under field conditions and highlighted future prospects for sustainable agricultural productivity.


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.


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.


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