scholarly journals Harnessing the Rhizosphere of the Halophyte Grass Aeluropus littoralis for Halophilic Plant-Growth-Promoting Fungi and Evaluation of Their Biostimulant Activities

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 784
Author(s):  
Mohamed Tarroum ◽  
Walid Ben Romdhane ◽  
Ahmed Abdelrahim Mohamed Ali ◽  
Fahad Al-Qurainy ◽  
Abdullah Al-Doss ◽  
...  
Keyword(s):  
Plant Growth ◽  
Nutrient Solution ◽  
Dna Sequences ◽  
Growth Media ◽  
Chemical Fertilizers ◽  
Aeluropus Littoralis ◽  
Research Activities ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Hydroponic Systems

Hydroponic systems have gained interest and are increasingly used in hot and dry desert areas. Numbers of benefits are offered by hydroponic systems such as the ability to save water, enhance nutrients use efficiency, easy environmental control, and prevention of soil-borne diseases. However, the high consumption of chemical fertilizers for nutrient solution and the sensitivity of closed hydroponic systems to salinity are issues that need solutions. Thus, the main goal of our research activities is to isolate plant growth promoting fungi in order to develop sustainable hydroponic systems. We are working on isolating and testing the possibility to incorporate the cell-free filtrate (CFF) of plant growth promoting fungi (PGPF) in the composition of the nutrient solution. In this work, we isolated six strains of PGPF from the rhizosphere of the halophyte grass Aeluropus littoralis. Phylogenetic analyses of DNA sequences amplified by ITS1 and ITS4 primers identified the isolated fungi as: Byssochlamys spectabilis, Chaetomium globosum, Cephalotheca foveolata, Penicillium melinii, Alternaria tenuissima, and Nigrospora chinensis. The promoting of vigor in tobacco seedlings was used as criteria to evaluate the biostimulant activity of these fungi by adding either their mycelia (DE: direct effect) or their cell-free filtrates (CFF: indirect effect) to the plant-growth media. The best significant growth stimulation was obtained with plants treated by B. spectabilis. However, only the CFFs of Byssochlamys spectabilis (A5.1) and Penicillium melinii (A8) when added at a dilution factor of 1/50 to half-strength nutritive solution (0.5NS) resulted in significant improvement of all assessed growth parameters. Indeed, the A5.1CFF and A8CFF in 0.5NS induced a significant better increase in the biomass production when compared to NS or 0.5NS alone. All fungi produced indole acetic acid in the CFFs, which could be one of the key factors explaining their biostimulant activities. Furthermore, six genes involved in nitrogen-metabolism (NR1 and NRT1), auxin biosynthesis (Tryp1 and YUCCA6-like), and brassinosteroid biosynthesis (DET2 and DWF4) were shown to be induced in roots or leaves following treatment of plants with the all CFFs. This work opens up a prospect to study in deep the biostimulant activity of PGPFs and their applications to decrease the requirement of chemical fertilizers in the hydroponic growing systems.

scholarly journals Selection of the Root Endophyte Pseudomonas brassicacearum CDVBN10 as Plant Growth Promoter for Brassica napus L. Crops

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1788
Author(s):  
Alejandro Jiménez-Gómez ◽  
Zaki Saati-Santamaría ◽  
Martin Kostovcik ◽  
Raúl Rivas ◽  
Encarna Velázquez ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Dry Weight ◽  
Bacterial Endophytes ◽  
Chemical Fertilizers ◽  
Brassica Napus L ◽  
Bacterial Microbiome ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Pseudomonas Brassicacearum

Rapeseed (Brassica napus L.) is an important crop worldwide, due to its multiple uses, such as a human food, animal feed and a bioenergetic crop. Traditionally, its cultivation is based on the use of chemical fertilizers, known to lead to several negative effects on human health and the environment. Plant growth-promoting bacteria may be used to reduce the need for chemical fertilizers, but efficient bacteria in controlled conditions frequently fail when applied to the fields. Bacterial endophytes, protected from the rhizospheric competitors and extreme environmental conditions, could overcome those problems and successfully promote the crops under field conditions. Here, we present a screening process among rapeseed bacterial endophytes to search for an efficient bacterial strain, which could be developed as an inoculant to biofertilize rapeseed crops. Based on in vitro, in planta, and in silico tests, we selected the strain Pseudomonas brassicacearum CDVBN10 as a promising candidate; this strain produces siderophores, solubilizes P, synthesizes cellulose and promotes plant height in 5 and 15 days-post-inoculation seedlings. The inoculation of strain CDVBN10 in a field trial with no addition of fertilizers showed significant improvements in pod numbers, pod dry weight and shoot dry weight. In addition, metagenome analysis of root endophytic bacterial communities of plants from this field trial indicated no alteration of the plant root bacterial microbiome; considering that the root microbiome plays an important role in plant fitness and development, we suggest this maintenance of the plant and its bacterial microbiome homeostasis as a positive result. Thus, Pseudomonas brassicacearum CDVBN10 seems to be a good biofertilizer to improve canola crops with no addition of chemical fertilizers; this the first study in which a plant growth-promoting (PGP) inoculant specifically designed for rapeseed crops significantly improves this crop’s yields in field conditions.

Effect of 2,4-D and inoculation with Azorhizobium caulinodans on maize

2006 ◽  
Vol 54 (1) ◽  
pp. 121-125 ◽  
Author(s):  
S. P. Saikia ◽  
S. P. Saikia ◽  
V. Jain ◽  
V. Jain ◽  
G. C. Srivastava ◽  
...  
Keyword(s):  
Plant Growth ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Azorhizobium Caulinodans ◽  
Chemical Fertilizers ◽  
Promoting Effect ◽  
Chemical Fertilization ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Produce Plant

Research over the last few years has shown that inoculation with nitrogen-fixing bacteria of the genus Azorhizobium presents an alternative for (or supplement to) chemical fertilization, mainly due to the capability of the bacteria to produce plant growth- promoting hormones. The Azorhizobium caulinodans strain ORS 571 in combination with 2,4-D was able to colonize the root interior of an Indian maize cultivar. After transplanting to pots, it was noticed that nodulated and Azorhizobium -treated plants showed higher chlorophyll content in the leaf and enhanced nitrate reductase activity, leading to higher yield as compared to the control plants (non-nodulated). A plant growth-promoting effect was clearly visible in all inoculated plants examined. nodulated plants treated with Azorhizobium had higher physiological activities as compared to plants treated only with Azorhizobium . Azorhizobium therefore creates potentially better symbiosis in the form of para -nodules and promotes a higher level of nitrogen fixation, leading to better growth and plant development, with reduced requirements for chemical fertilizers.

scholarly journals Quantification of Azospirillum brasilense FP2 Bacteria in Wheat Roots by Strain-Specific Quantitative PCR

2015 ◽  
Vol 81 (19) ◽  
pp. 6700-6709 ◽  
Author(s):  
Maria Isabel Stets ◽  
Sylvia Maria Campbell Alqueres ◽  
Emanuel Maltempi Souza ◽  
Fábio de Oliveira Pedrosa ◽  
Michael Schmid ◽  
...  
Keyword(s):  
Plant Growth ◽  
Quantitative Pcr ◽  
Dna Sequences ◽  
Azospirillum Brasilense ◽  
Plant Growth Promoting Bacteria ◽  
Genome Sequences ◽  
Wheat Roots ◽  
Content Type ◽  
Plant Growth Promoting ◽  
Growth Promoting

ABSTRACTAzospirillumis a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide.Azospirillum brasilensestrains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of the inoculant in the rhizosphere, which is not always achieved. The objective of this study was to develop quantitative PCR protocols for the strain-specific quantification ofA. brasilenseFP2. A novel approach was applied to identify strain-specific DNA sequences based on a comparison of the genomic sequences within the same species. The draft genome sequences ofA. brasilenseFP2 and Sp245 were aligned, and FP2-specific regions were filtered and checked for other possible matches in public databases. Strain-specific regions were then selected to design and evaluate strain-specific primer pairs. The primer pairs AzoR2.1, AzoR2.2, AzoR5.1, AzoR5.2, and AzoR5.3 were specific for theA. brasilenseFP2 strain. These primer pairs were used to monitor quantitatively the population ofA. brasilensein wheat roots under sterile and nonsterile growth conditions. In addition, coinoculations with other plant growth-promoting bacteria in wheat were performed under nonsterile conditions. The results showed thatA. brasilenseFP2 inoculated into wheat roots is highly competitive and achieves high cell numbers (∼107CFU/g [fresh weight] of root) in the rhizosphere even under nonsterile conditions and when coinoculated with other rhizobacteria, maintaining the population at rather stable levels for at least up to 13 days after inoculation. The strategy used here can be applied to other organisms whose genome sequences are available.

scholarly journals Morphophysiological, Enzymatic, and Elemental Activity in Greenhouse Tomato Saladette Seedlings from the Effect of Plant Growth-Promoting Rizobacteria

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1008
Author(s):  
Tomás Juan Álvaro Cervantes-Vázquez ◽  
Ana Alejandra Valenzuela-García ◽  
María Gabriela Cervantes-Vázquez ◽  
Tania Lizzeth Guzmán-Silos ◽  
Erika Lagunes Fortiz ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Plant Growth ◽  
Nutrient Solution ◽  
Stem Diameter ◽  
Production Costs ◽  
Abiotic Factor ◽  
Distilled Water ◽  
Plant Growth Promoting ◽  
Growth Promoting

The tomato is a widely cultivated and consumed vegetable globally. Comarca Lagunera is an important tomato-exporting region of Mexico. Salinity is an abiotic factor that reduces productivity and increases production costs. To advance growing period, there is high demand for the sustainable production of seedlings. Plant-growth-promoting rhizobacteria (PGPR) are characterized by improving plant growth through different mechanisms and can be an option for reducing the misuse of chemical fertilizers. The importance of the application of strains, evaluating various inoculation methods (in seed, soil, foliar spraying, and root immersion), should be evaluated to propose biofertilization packages in a specific crop. Thus, the study aimed to determine the effect of PGPR (Bacillus paralicheniformis, Acinetobacter guillouiae, Aeromonas caviae, and Pseudomonas lini) vs. nutrient solution and distilled water in the seedlings stage of saladette-type tomato on morphophysiological variables, nitrate reductase (NR) enzyme activity, and plant minerals via tissue analysis under greenhouse conditions. The four PGPR were inoculated by different methods (inoculation in seed, sprinkling, and both) in saladette-type tomato seedlings under greenhouse conditions and evaluated in vivo 40 days after sowing for morphophysiological variables, such as seedling height; stem diameter; root displaced volume; fresh and dry weight matter of the leaves, stems, and roots; leaf area; and nitrate reductase enzyme activity. The effect of the inoculation of PGPR showed significant results for Pseudomonas lini vs. the control, with 40% higher values, on average, for plant height, stem diameter, displaced root volume, and fresh weight of root, leaf, and stem. The response of enzymatic and mineral content in seedlings was variable with nutrient solution and significant with distilled water. Studies related to the promotion of plants in the subsequent phenological stages of a tomato, considering the selected PGPR, should be considered in future research.

scholarly journals Role of biochar, compost and plant growth promoting rhizobacteria in the management of tomato early blight disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mujahid Rasool ◽  
Adnan Akhter ◽  
Gerhard Soja ◽  
Muhammad Saleem Haider
Keyword(s):  
Plant Growth ◽  
Early Blight ◽  
Alternaria Solani ◽  
Plant Growth Promoting Rhizobacteria ◽  
Application Rate ◽  
Growth Media ◽  
Soil Substrate ◽  
Plant Growth Promoting ◽  
Growth Promoting

AbstractThe individual role of biochar, compost and PGPR has been widely studied in increasing the productivity of plants by inducing resistance against phyto-pathogens. However, the knowledge on combined effect of biochar and PGPR on plant health and management of foliar pathogens is still at juvenile stage. The effect of green waste biochar (GWB) and wood biochar (WB), together with compost (Comp) and plant growth promoting rhizobacteria (PGPR; Bacillus subtilis) was examined on tomato (Solanum lycopersicum L.) physiology and Alternaria solani development both in vivo and in vitro. Tomato plants were raised in potting mixture modified with only compost (Comp) at application rate of 20% (v/v), and along with WB and GWB at application rate of 3 and 6% (v/v), each separately, in combination with or without B. subtilis. In comparison with WB amended soil substrate, percentage disease index was significantly reduced in GWB amended treatments (Comp + 6%GWB and Comp + 3%GWB; 48.21 and 35.6%, respectively). Whereas, in the presence of B. subtilis disease suppression was also maximum (up to 80%) in the substrate containing GWB. Tomato plant growth and physiological parameters were significantly higher in treatment containing GWB (6%) alone as well as in combination with PGPR. Alternaria solani mycelial growth inhibition was less than 50% in comp, WB and GWB amended growth media, whereas B. subtilis induced maximum inhibition (55.75%). Conclusively, the variable impact of WB, GWB and subsequently their concentrations in the soil substrate was evident on early blight development and plant physiology. To our knowledge, this is the first report implying biochar in synergism with PGPR to hinder the early blight development in tomatoes.

scholarly journals Distinct Root Microbial Communities in Nature Farming Rice Harbor Bacterial Strains With Plant Growth-Promoting Traits

2021 ◽  
Vol 4 ◽  
Author(s):  
Grace Flavyeliz Sinong ◽  
Michiko Yasuda ◽  
Yoshiyuki Nara ◽  
Chol Gyu Lee ◽  
Khondoker Mohammad Golam Dastogeer ◽  
...  
Keyword(s):  
Plant Growth ◽  
Farming Systems ◽  
Farming System ◽  
Bacterial Strains ◽  
Chemical Fertilizers ◽  
Distinct Root ◽  
Rice Growth ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Root Microbiome

A nature farming system is an ecological farming practice that entails cultivating crops without using chemical fertilizers and pesticides. To understand the diversity and functions of root microbiomes associated with nature farming systems, we compared the root microbial community of rice under nature farming conditions with those under conventional farming conditions. High-throughput amplicon analysis demonstrated a higher abundance and greater diversity of the root microbiome under unfertilized nature farming conditions than under conventional conditions. The application of chemical fertilizers reduced the microbial diversity and abundance of some beneficial taxa important for plant growth and health. Subsequently, we isolated and identified 46 endo- and epiphytic bacteria from rice roots grown under nature farming conditions and examined their plant growth-promoting activity. Six potential isolates were selected for plant growth assessment in insoluble P- and K-containing media. Most of the isolates promoted rice growth, and Pseudomonas koreensis AEPR1 was able to enhance rice growth significantly in both insoluble P- and K-containing media. Our data indicated that nature farming systems create a distinct root microbiome that is comparatively more diverse and supports plant growth under low-input cultivation practices than under conventional practices. The potential isolates could be exploited as sources with potential applications in sustainable agriculture.

scholarly journals EFFECTS OF OXYFERTIGATION AND PLANT GROWTH PROMOTING RHIZOBACTERIA ON GREENHOUSE LETTUCE GROWN IN PERLITE

2020 ◽  
Vol 19 (1) ◽  
pp. 97-105
Author(s):  
Gölgen Bahar Öztekin ◽  
Yüksel Tüzel
Keyword(s):  
Plant Growth ◽  
Nutrient Solution ◽  
Plant Growth Promoting Rhizobacteria ◽  
Quality Parameters ◽  
Oxygen Enrichment ◽  
Control Treatment ◽  
Combined Application ◽  
Growing Medium ◽  
Plant Growth Promoting ◽  
Growth Promoting

This study was conducted in order to determine the effects of oxygen enrichment of nutrient solution coupled with plant growth promoting rhizobacteria on soilless grown iceberg lettuce (cv. ‘Papiro’) production. Seeds were treated with Bacillus subtilis, Pseudomonas putida, P. fluorescens, P. punonensis and combined application of B. subtilis + P. fluorescens and were sown into vermicompost : peat (1 : 1.5, v/v) mixture on January 14th, 2015. After germination in growth chamber, seedlings were moved to a greenhouse for seedling growing till they were ready for planting. Seedlings were transplanted to the polyethylene greenhouse 35 days after sowing. Perlite as growing medium was used in open-system soilless culture. Nutrient solution was aerated with an air compressor and applied to plants 2 days after planting with drip irrigation. To diffuse oxygen into nutrient solution in large bubbles, a circular air-stone commonly used in fisheries was used. The nutrient solution without oxyfertigation and plants not treated with bacteria constituted the control treatment. Experiments were conducted in randomized plots design with 2 factors and 3 replications. Heads were harvested 2 months after transplanting. Yield and head quality parameters of head were determined. It was concluded that oxygen enrichment of nutrient solution through a compressor (aeration) provided increases in yield and plant growth. Especially root development, head size and leaf number were higher in plants grown with aerated nutrient solution. Among the tested bacteria, B. subtilis, P. fluorescens and B. subtilis + P. fluorescens were found promising due to the their higher performance under aerated conditions on greenhouse lettuce grown in perlite.

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