Analyzing Single and Combined Cultures of Plant Growth-Promoting Rhizobacteria Isolates from Afghanistan as a Potential Biofertilizer for Rice Growth and Development (original) (raw)
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Microbes and Environments, 2019
To develop biofertilizers for rice in Afghanistan, 98 plant growth-promoting rhizobacteria were isolated from rice plants and their morphological and physiological characteristics, such as indole-3-acetic acid production, acetylene reduction, phosphate and potassium solubilization, and siderophore production, were evaluated. The genetic diversity of these bacteria was also analyzed based on 16S rRNA gene sequences. Of 98 bacteria, 89.7% produced IAA, 54.0% exhibited nitrogenase activity, and 40% showed phosphate solubilization and siderophore production. Some isolates assigned to Pseudomonas (brassicacearum, chengduensis, plecoglossicida, resinovorans, and straminea) formed a relationship with rice, and P. resinovorans and P. straminea showed nitrogen fixation. Rhizobium borbori and R. rosettiformans showed a relationship with rice plants and nitrogen fixation. Among the isolates examined, AF134 and AF137 belonging to Enterobacter ludwigii and P. putida produced large amounts of IAA (92.3 μg mL-1) and exhibited high nitrogenase activity (647.4 nmol C 2 H 4 h-1), respectively. In the plant growth test, more than 70% of the inoculated isolates showed significantly increased root and shoot dry weights. Highly diverse bacterial isolates showing promising rice growth-promoting traits were obtained from Afghanistan alkaline soils.
American Journal of Agricultural and Biological Science
Biofertilizer is a relatively safer, environmentally friendly and cost-effective approach as an alternative to reduce chemical fertilizer usage. The selection of bacterial strains with multiple beneficial characteristics are important to maximize the effectiveness on the host plant. Due to aforementioned interest, several Plant Growth-Promoting Rhizobacterial (PGPR) and rhizobial strains were isolated from rice and legume roots, respectively, at four locations in Malaysia namely Universiti Putra Malaysia (UPM), Serdang, Selangor; Besut, Terengganu; Tunjung, Kelantan and Sik, Kedah. Bacterial isolations were undertaken to select the best isolates which exhibit multiple beneficial effects to the rice plant and a total of 205 bacterial strains were isolated and categorized as follows; 94 rhizospheric and 107 endophytic bacteria from rice roots, one rhizobial strain from soybean and three from Mimosa pudica. These isolates were screened for their abilities to fix N 2 and solubilize phosphate; 52 were positive for both tests. The selected isolates were then tested for IAA production and other biochemical tests such as potassium solubilization, hydrolyzing enzymes (cellulase and pectinase) and iron siderophore productions. Four isolates, namely UPMB19 (rhizospheric PGPR from Tunjung, Kelantan), UPMB20 (endophytic PGPR from Besut, Terengganu), UPMR30 (rhizobia from soybean) and UPMR31 (rhizobia from Mimosa) were selected for subsequent plant inoculation tests with UPMB10, a PGPR isolated from oil palm root, as the reference strain. Based on 16S rDNA gene sequencing, these bacterial strains were identified under several genera: Lysinibacillus, Alcaligenes, Bradyrhizobium, Rhizobium and Bacillus, respectively. Results of plant inoculation test indicated that UPMB19 significantly enhanced the seedling height at the early growth stage (7 days after transplanting, DAT) which could be attributed to the higher N 2 fixation rate of this strain as compared to the other strains, except UPMB20. UPMB10 and UPMR31 also showed significant effects with increased seedling height and Total Dry Weight (TDW) at the later stage (14 DAT) possibly due to the higher bacterial population and IAA produced as observed in the residual nutrient solution without addition of fertilizer-N. This study has successfully demonstrated the effectiveness of locally isolated PGPR and rhizobial strains with multiple beneficial characteristics on early growth and vigor of rice seedlings under controlled condition. The result proved to be a vital information in the development of a liquid biofertilizer for rice; thus further studies will be done to evaluate the effectiveness of these isolates under glasshouse and field conditions on growth, tillering and yield of rice.
Growth and Yield Response of Upland Rice to Application of Plant Growth-Promoting Rhizobacteria
Journal of Plant Growth Regulation
This study evaluated the effects of plant growth-promoting rhizobacteria (PGPR) isolates in enhancing upland rice growth and yield. Bacteria were isolated, screened for growth-promoting activities in vitro, biochemically identified, and tested under screenhouse conditions at the Philippine Rice Research Institute (PhilRice). Isolates exhibited growth-promoting activities, such as indole-3-acetic acid (IAA) production, tricalcium phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, siderophore production, and starch hydrolysis. The screenhouse experiment was conducted with upland rice (PSB Rc23) as the test crop, sterilized and natural soils, and recommended rate of inorganic fertilizers (RRIF) as other source variables. Results showed that significantly heavier shoot and root fresh weights are evident in plants grown in sterilized soil. Plants treated with full RRIF exhibited superior growth in terms of plant height, shoot and root weights, and grain yield. Among inoculated and fertilized plants, comparable growth promotion was obtained with Acidovorax delafieldii combined with half inorganic fertilizer rate, in terms of root fresh weight, shoot and root dry weights, plant height, grain yield, and nitrogen, phosphorus, and potassium (NPK) uptake. Overall findings show that PGPR (A. delafieldii) in combination with 50% RRIF is as effective as full RRIF in enhancing growth and yield of PSB Rc23 rice, implying that dependence on chemical fertilizer can be reduced utilizing this PGPR. However, further evaluation of these bacterial isolates in actual field conditions is necessary to uncover their efficiency as potential biofertilizer.
Agriculture
Upland rice farming plays a crucial role in ensuring food security in Indonesia. This study aimed to evaluate the impact of plant growth-promoting rhizobacteria (PGPR) isolates on the growth of upland rice. The bioassay and pot experiments were conducted to select the capable isolates of PGPR and to investigate the effect of the PGPR inoculant on the N fertilizer efficiency and agronomic traits of upland rice. The bacterial isolates were identified through a biochemical analysis and tested under controlled greenhouse conditions. The selected PGPR inoculant was formulated as a liquid biofertilizer (LB). The three capable isolates were obtained to fix nitrogen, produce indole-3-acetic acid (IAA), organic acid, and nitrogenase activity and were identified through a biomolecular analysis as Delftia tsuruhatensis strain D9, Delftia sp. strain MS2As2, and Bacillus sp. The application of the LB into the soil at a dose of 10 L ha−1 and 50 kg ha−1 N resulted in a grain yield of 29.81 g pot−1...
Efficacy of Rhizobacteria to Promote the Growth and Increase the Yield of Several Rice Cultivars
Journal of Biology, Agriculture and Healthcare, 2021
Rice is still play important role as staple food for most of Indonesian population; consequently Indonesia is greatly relying on rice production to maintain food security. This plant is commonly cultivated with intensive use of synthetic agrochemicals such as synthetic chemical fertilizers and pesticides. However, the improper use of agrochemicals may result in adverse effects to the environment including biotic and abiotic components. This study was conducted to evaluate the efficacy of rhizobacteria formulation to promote the growth and increase the yield of four rice cultivars that commonly grown in Indonesia i.e. Ciherang, Cigeulis, Inpari 33, and IR64. Experiment was done in a green house with three concentrations of rhizobacteria formulation i.e. 0%, 1%, and 2% (v/v). Several parameters were observed in this study such as seedling height, leaf chlorophyll content of seedling, plant height at 50 days after transplanting (DAT), leaf chlorophyll content at 50 DAT, number of tillers per plant at 50 DAT, number of productive tillers per plant, and yield per plant. Results showed that significant interactions were observed between rice cultivar and concentration of rhizobacteria formulation in all parameters observed. Rice cultivar IR64 consistently showed superior growth and yield among four rice cultivars tested. Except for cultivar IR64, rhizobacteria concentration at 2% showed superior results compared to 1% and 0% for all parameters observed. This study proved that rhizobacteria formulation containing Stenotrophomonas maltophilia Sg3 and Enterobacter cloacae Al7Kla effectively promoted the growth and increase the yield of four rice cultivars that commonly cultivated in Indonesia, suggested that this rhizobacteria formulation is promising bio-agent to be used for rice production in Indonesia.
Isolation and in vitro screening of plant growth promoting rhizobacteria from Barak Cenana red rice
PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON BIOSCIENCES AND MEDICAL ENGINEERING (ICBME2019): Towards innovative research and cross-disciplinary collaborations, 2019
This research aimed to get bacterial isolate from rhizospheric soil of Barak Cenana, one of red rice cultivar. Rhizosphere area is a potential source as plant growth promoting rhizobacteria (PGPR) can be isolated and utilized to support growth and productivity of Barak Cenana red rice in the future. The potential of isolates as PGPR inoculants was determined based on the ability of the isolates to produce siderophores, Indole Acetic Acid (IAA), and phosphate solubilization, by in vitro screening. The results suggested that G4c isolate has potential as plant growth promoting ability, based on the promising observation of siderophores production, the highest concentration of Indole Acetic Acid (IAA) production, and phosphate solubilization. Based on 16S rRNA sequencing by using 785F and 907R primer set, G4c isolates were tentatively identified as Rhizobium pusense.
Plant growth promoting rhizobacteria: potential for sustainable agriculture
2021
With growing world population, there is an exponential increase in demand for food. The use of chemical fertilizers to improve crop productivity is associated with considerable health risks, environmental hazards, and costs. In this scenario, biofertilizers or microbial fertilizers appear to be an important alternative strategy. Therefore, this manuscript was proposed document the importance of biofertilizers and plant growth promoting rhizobacteria (PGPR) as candidates for it production. The various underlying mechanisms promoting the growth of plants, different types and comparison with chemical fertilizers are compiled in this review and the potential for developing a sustainable agriculture.
Plant Growth Promoting Rhizobacteria as Biofertilizers: Application in Agricultural Sustainability
Acta Scientific Microbiology, 2022
The demand for agricultural productivity has increased dramatically as a result of civilization and industrialization. Chemical fertilizers and pesticides increase agricultural yields, but they can degrade soil fertility and quality, posing environmental risks. As a result, the need for environmentally friendly biological agents, such as plant growth promoting rhizobacteria, has skyrocketed in order to improve soil fertility and agricultural operations while also protecting environmental health. The active activity of plant growth promoting rhizobacteria in the rhizosphere, which promotes the growth and development of host plants, has long been known. Plants growing compounds generated by these microbes have a direct or indirect effect on plant physiology, making them valuable agricultural goods in high demand. The plant's resistance power has been increased against biotic and abiotic stress conditions thanks to the PGPR'
Advances in Agriculture
Plant growth-promoting rhizobacteria (PGPR) are beneficial soil microorganisms that colonize plant roots and enhance plant growth by a wide variety of mechanisms. In this work, five Bacillus and two Cyanobacteria isolates were successfully isolated and characterized. A pot experiment was conducted to evaluate the effect of PGPR on the growth of three cultivars of rice seedlings. Pots were laid down in a complete random design and 100 ml of spore and Cyanobacteria suspension were poured on the soil surface surrounding each seedling. After 45 days, the seedlings were uprooted and shoot and root parameters were recorded. All the Bacillus and Cyanobacteria isolates showed positive effects on the growth of rice seedlings as compared to control; however, their effectiveness varies from isolate to isolate and also from cultivar to cultivar. Bacterial isolates B3 and B5 showed the highest mean value and statistically significant difference ( P < 0.05 ) in most of the root and shoot param...
Plant Growth Promoting Rhizobacteria and Sustainable Agriculture
Microbial Strategies for Crop Improvement, 2009
The diverse groups of bacteria in close association with roots and capable of stimulating plant growth by any mechanism(s) of action are referred to as plant growth-promoting rhizobacteria (PGPR). They affect plant growth and development directly or indirectly either by releasing plant growth regulators (PGRs) or other biologically active substances, altering endogenous levels of PGRs, enhancing availability and uptake of nutrients through fixation and mobilization, reducing harmful effects of pathogenic microorganisms on plants and/or by employing multiple mechanisms of action. Recently, PGPR have received more attention for use as a biofertilizer for the sustainability of agro-ecosystems. Selection of efficient PGPR strains based on well-defined mechanism(s) for the formulation of biofertilizers is vital for achieving consistent and reproducible results under field conditions. Numerous studies have suggested that PGPR-based biofertilizers could be used as effective supplements to chemical fertilizers to promote crop yields on sustainable basis. Various aspects of PGPR biotechnology are reviewed and discussed.