Effect of PGPR on enzymatic activities of rice (Oryza sativa L.) under salt stress (original) (raw)
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Effect of PGPR on growth promotion of rice (Oryza sativa L.) under salt stress
Large areas of the world are not usable from the agricultural perspective due to the constraints posed by nature and human activities making the soil less or unproductive. Soil salinity is a major abiotic stress worldwide. The development of salt-tolerant crops is not always an economical approach for sustainable agriculture, whereas microbial inoculation to alleviate salt stress is a better option because it minimizes production costs and environmental hazards. Plant Growth Promoting Rhizobacteria (PGPR) have been indicated as efficient growth enhancer of crop plants and the growth promoting effect under stress conditions has also been suggested to be beneficial for crop production. In this study two rice genotypes ADT43 and IR50 treated with PGPR (Pseudomonas strains PF1 and TDK1) were subjected to 100mM NaCl, following IRRI method under laboratory environment. The salt stress symptoms included stunted growth, poor root growth and the leaves from the tip turned to white. The results of the experiment indicated that the plant height, root length, dry weight of shoot and root were significantly increased due to Pseudomonas strain treatment even under salt stress whereas the plants grown without any treatment had less growth. ADT43 genotype treated with Pseudomonas strain TDK1 recorded better plant development under salt stress.
2018
The effects of the inoculation of plant growth promoting rhizobacterial (PGPR) strains Pseudomonas fluorescence strain P2, Pseudomonas jessenii R62, Pseudomonas synxantha R81, Pseudomonas koreensis strainYB1 and Arthrobacter nitroguajacolicus strain YB3 on CSR-36 (Salinity tolerance) and IR-64 (Salinity sensitive) genotypes of rice were studied under three level of saline alkali soil stress. The Level I have 9.18 pH and 2.05 ds/m Electrical conductivity (Ec), the Level II have 9.38 pH and 2.47 ds/m Ec, while the Level III have 9.63pH and 3.05 ds/m Ec. PGPRs, Pseudomonas jessenii, R62, Pseudomonas synxantha, R81 were used as a consortium. Most of the inoculated plants had remarkably higher plant height, fresh weight, chlorophyll, carotenoid content, lowered electrolyte leakage (EL) and Malondialdehyde (MDA) content as compare to uninoculated plants in all the level of stress. The PGPRs efficiently reduced the proline and superoxide dismutase (SOD) activity in both the genotype of ric...
PLOS ONE, 2020
In this study, we characterized, identified, and determined the effect of salt-tolerant PGPR isolated from coastal saline areas on rice growth and yield. A total of 44 bacterial strains were isolated, and 5 were found to be tolerant at high salt concentration. These isolates were further characterized for salinity tolerance and beneficial traits through a series of quantitative tests. Biochemical characterization showed that bacterial survivability decreases gradually with the increase of salt concentration. One of the strains, UPMRB9, produced the highest amount of exopolysaccharides when exposed to 1.5M of NaCl. Moreover, UPMRB9 absorbed the highest amount of sodium from the 1.5M of NaCl-amended media. The highest floc yield and biofilm were produced by UPMRE6 and UPMRB9 respectively, at 1M of NaCl concentration. The SEM observation confirmed the EPS production of UPMRB9 and UPMRE6 at 1.5M of NaCl concentration. These two isolates were identified as Bacillus tequilensis and Bacillus aryabhattai based on the 16S rRNA gene sequence. The functional group characterization of EPS showed the presence of hydroxyl, carboxyl, and amino groups. This corresponded to the presence of carbohydrates and proteins in the EPS and glucose was identified as the major type of carbohydrate. The functional groups of EPS can help to bind and chelate Na + in the soil and thereby reduces the plant's exposure to the ion under saline conditions. The plant inoculation study revealed significant beneficial effects of bacterial inoculation on photosynthesis, transpiration, and stomatal conductance of the plant which leads to a higher yield. The Bacillus tequilensis and Bacillus aryabhattai strains showed good potential as PGPR for salinity mitigation practice for coastal rice cultivation.
Effect of salt-tolerant PGPR on the activity of some microbial and plant enzymes under saline stress
This experiment was conducted under greenhouse conditions using a randomized complete block design (RCBD) with three replicates in the experimental farm station of Fac. Agric. at Moshtohor during 2011 season.This research aims to study the effect of tomato and pepper inoculation with salt-tolerant PGPR strains (Pseudomonas fluorescence D23, Bacillus pumilus D135 and Azospirillum lipoferum D178) for tomato while, (Bacillus megaterium D159, Paenibacillus alvie D139 and Azospirillum lipoferum D207) for pepper in combination with humic acid and organic manure (compost) on some microbial enzymes activity such as dehydrogenase, phosphatase, nitrogenase and oxidative enzymes like nitrate reductase, peroxidase and polyphenol oxidase. The application of salt-tolerant PGPR in combination with compost at a rate of 10 ton/fed. and humic acid at a rate of 4 kg/fed. gave positive impact on the tested enzymes which resulted to beneficial effect on tomato and pepper cultivated under saline stress.
Applied Biological Chemistry, 2021
Salinization of agricultural lands, particularly rice paddies, results in the drastic decline of crop yields. Soil salinization impacts the plant physiology by inducing salt stress which may leads to osmotic stress, ionic stress and water-related nutrient imbalance. These imbalances necessitate the need for plants to produce osmolytes including proline and glycine betaine. This study aimed to elucidate the dynamic changes in proline and glycine betaine accumulation modulated by the inoculation of Brevibacterium linens RS16 in salt-sensitive and moderately salt-tolerant rice plants under salt stress conditions. This study showed the interaction of four major factors including rice genotypes with differing tolerance to salt stress, length of exposure to salt stress, level of salt stress and effects of inoculation. Salt stress resulted in significant reduction in plant growth parameters with the salt-sensitive rice genotype (IR29) having a more significant growth reduction. Both the sa...
Frontiers in Microbiology
Salt-tolerant plant growth-promoting rhizobacteria (PGPR) can improve soil enzyme activities, which are indicators of the biological health of the soil, and can overcome the nutritional imbalance in plants. A pot trial was executed to evaluate the effect of inoculation of different salt-tolerant PGPR strains in improving soil enzyme activities. Three different salinity levels (original, 5, and 10 dS m–1) were used and maize seeds were coated with the freshly prepared inocula of ten different PGPR strains. Among different strains, inoculation of SUA-14 (Acinetobacter johnsonii) caused a maximum increment in urease (1.58-fold), acid (1.38-fold), and alkaline phosphatase (3.04-fold) and dehydrogenase (72%) activities as compared to their respective uninoculated control. Acid phosphatase activities were found to be positively correlated with P contents in maize straw (r = 0.96) and grains (r = 0.94). Similarly, a positive correlation was found between alkaline phosphatase activities and...
2017
Bacteria possessing ACC deaminase activity reduce the level of stress ethylene conferring resistance and stimulating growth of plants under various biotic and abiotic stresses. Therefore, this study was carried out at National Agriculture Research Centre Islamabad to screen rhizobacteria containing ACC deaminase for inducing salt tolerance and improving rice plant growth and enhancement in paddy production under salt-stressed conditions. (ECe=9.65 dS m-1) during June, 2015 to November, 2016. Rice variety Basmati-385 seeds were inoculated with rhizobacterial strains which were: SBCC (M9), RPR (32), RPR (33), WPS (8) PBS, SBCC (M8) and RPR (41). Salinity (9.65dS m-1) was artificially developed using salts. This study resulted that rice crop improved growth and yield under salt stressed conditions with the induction of salt tolerance through ACC deaminaze PGPR and this was accomplished with the reduction in ethylene production. Reduction in sodium uptake by the utilization of different...
Journal of Plant Pathology & Microbiology, 2015
Maize (Zea mays L.) biomass and its allied attributes were assessed under salinity stress and three plant growthpromoting rhizobacteria (Pseudomonas fluorescens, Pseudomonas putida and Azotobacter vinelandii) treatments. The three PGPRs inocula exhibited a different pattern of shoot growth under both normal and saline stress conditions. Plant biomass, carbohydrates, protein and chlorophyll content were reduced by saline stress, however application of PGPRs treatments improved them either in comparison to control samples or to untreated samples under saline stress. Lipids and antioxidant enzymes (catalase and peroxidase) increased as a response for saline stress as an indication of oxidative stress. Plant growth-promoting rhizobacteria treatment restored them to semi-normal levels. Sodium/ potassium balance was observed to be disturbed by saline stress through higher levels of Na + and lower levels of K + , but treating samples balance was clearly restored close to normal conditions especially in the root system.
Rice (Oryza sativa L.) is highly susceptible to the rhizosphere salinity than other cereals. High sensitivity has been observed , mainly at vegetative and reproductive stages in rice. It is the duty of plant physiologists to comprehend the growth, development, and physiological processes of rice plants under stress. This paper includes the overview of rice growth and developmental processes influenced by salt stress and the regulation pathways involved in these processes. It also includes the promising salt tolerance strategies, i.e., genetic modification techniques, agronomic practices to improve rice growth, yield, and role of phytohormones and their management, especially inhibition of ethylene biosynthesis by using inhibitors 1-methylcyclopropene (1-MCP). Rice cultivation may be a first choice for improvement of salt tolerance through plant growth regulators and improved cultivation techniques. This study will significantly improve the understanding toward low rice grain yield and poor rice resistance under salt stress and will also stream scientific knowledge for effective utilization of salt affected soils by using different regulating ways.
The PGPR Mechanisms of Salt Stress Adaptation and Plant Growth Promotion
Agronomy
Worldwide crop productivity hampers severely due to the adverse effects of salinity. Global warming causes a rapid escalation of the salt-affected area, and new agricultural land is affected through saltwater intrusion. The ever-growing human population impulses to utilize the saline area for crop cultivation to ensure food security. Salinity resistance crops could be a promising substitute but with minor success because inappropriate tactics on saline soil management resulted in unsatisfactory yield. Salt-tolerant plant growth-promoting rhizobacteria (ST-PGPR) is considered an alternate way towards enhancing crop growth in saline ecosystems. It is reported that PGPR is enabled to produce exopolysaccharides which lead to biofilm formation and generate osmoprotectants and antioxidant enzymes that can significantly contribute to stimulating plant growth in the saline ecosystem. In addition, several plant growth-promoting characteristics of PGPR such as the acquisition of essential nut...