scholarly journals Isolation and Identification of Plant Growth Promoting Rhizobacteria from Cucumber Rhizosphere and Their Effect on Plant Growth Promotion and Disease Suppression

2016 ◽  
Vol 6 ◽  
Author(s):  
Shaikhul Islam ◽  
Abdul M. Akanda ◽  
Ananya Prova ◽  
Md. T. Islam ◽  
Md. M. Hossain
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Disease Suppression ◽  
Isolation And Identification ◽  
Plant Growth Promoting ◽  
Growth Promoting

scholarly journals Mixtures of Plant-Growth-Promoting Rhizobacteria Enhance Biological Control of Multiple Plant Diseases and Plant-Growth Promotion in the Presence of Pathogens

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Ke Liu ◽  
John A. McInroy ◽  
Chia-Hui Hu ◽  
Joseph W. Kloepper
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Pythium Ultimum ◽  
Plant Diseases ◽  
Disease Suppression ◽  
Plant Growth Promoting ◽  
Growth Promoting

Several studies have shown that mixtures of plant-growth-promoting rhizobacteria (PGPR) could enhance biological control activity for multiple plant diseases through the mechanisms of induced systemic resistance or antagonism. Prior experiments showed that four individual PGPR strains—AP69 (Bacillus altitudinis), AP197 (B. velezensis), AP199 (B. velezensis), and AP298 (B. velezensis)—had broad-spectrum biocontrol activity via antagonism in growth chambers against two foliar bacterial pathogens (Xanthomonas axonopodis pv. vesicatoria and Pseudomonas syringae pv. tomato) and one of two tested soilborne fungal pathogens (Rhizoctonia solani and Pythium ultimum). Based on these findings, the overall hypothesis of this study was that a mixture of two individual PGPR strains would exhibit better overall biocontrol and plant-growth promotion than the individual PGPR strains. Two separate greenhouse experiments were conducted. In each experiment, two individual PGPR strains and their mixtures were tested for biological control of three different diseases and for plant-growth promotion in the presence of the pathogens. The results demonstrated that the two individual PGPR strains and their mixtures exhibited both biological control of multiple plant diseases and plant-growth promotion. Overall, the levels of disease suppression and growth promotion were greater with mixtures than with individual PGPR strains.

scholarly journals Characterization of Selected Plant Growth-Promoting Rhizobacteria and Their Non-Host Growth Promotion Effects

2021 ◽  
Author(s):  
Di Fan ◽  
Donald L. Smith
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Content Type ◽  
Host Growth ◽  
Plant Growth Promoting ◽  
Growth Promoting

There are pressing needs to reduce the use of agrochemicals, and PGPR are receiving increasing interest in plant growth promotion and disease protection. This study follows up our previous report that the four newly isolated rhizobacteria promote the growth of Arabidopsis thaliana .

scholarly journals A Framework for the Selection of Plant Growth-Promoting Rhizobacteria Based on Bacterial Competence Mechanisms

2020 ◽  
Vol 86 (14) ◽  
Author(s):  
Carol V. Amaya-Gómez ◽  
Mario Porcel ◽  
Leyanis Mesa-Garriga ◽  
Martha I. Gómez-Álvarez
Keyword(s):  
Hydrogen Peroxide ◽  
Plant Growth ◽  
Decision Analysis ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Screening Strategy ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Selection Of

ABSTRACT The use of plant growth-promoting rhizobacteria (PGPR) is increasingly meaningful for the development of more environmentally friendly agricultural practices. However, often the PGPR strains selected in the laboratory fail to confer the expected beneficial effects when evaluated in plant experiments. Insufficient rhizosphere colonization is pointed out as one of the causes. With the aim of minimizing this inconsistency, we propose that besides studying plant growth promotion traits (PGP), the screening strategy should include evaluation of the microbial phenotypes required for colonization and persistence. As a model, we carried out this strategy in three Rhizobium sp. strains that showed phosphorus solubilization ability and production of siderophores. All strains displayed colonization phenotypes like surface spreading, resistance to hydrogen peroxide, and formed biofilms. Regarding their ability to persist, biofilm formation was observed to be influenced by pH and the phosphorus nutrient provided in the growth media. Differences in the competence of the strains to use several carbon substrates were also detected. As part of our framework, we compared the phenotypic characteristics of the strains in a quantitative manner. The data analysis was integrated using a multicriteria decision analysis (MCDA). All our results were scored, weighted, and grouped as relevant for PGP, colonization, or persistence. MCDA demonstrated that, when the phenotypes related to PGP and colonization are weighted over those for persistence, strain B02 performs better than the other two Rhizobium sp. strains. The use of our framework could assist the selection of more competent strains to be tested in greenhouse and field trials. IMPORTANCE Numerous plant growth-promoting rhizobacteria (PGPR) have been inoculated into the soil with the aim of improving the supply of nutrients to crop plants and decreasing the requirement of chemical fertilizers. However, sometimes these microbes fail to competitively colonize the plant roots and rhizosphere. Hence, the plant growth promotion effect is not observed. Here, we describe a new screening strategy aiming at the selection of more competent PGPR. We evaluated bacterial phenotypes related to plant growth promotion, colonization, and persistence. Our results demonstrated that despite the fact that our Rhizobium sp. strains successfully solubilized phosphorus and produced siderophores, their abilities to spread over surfaces, resist hydrogen peroxide, and form biofilms varied. Additionally, a multicriteria decision analysis was used to analyze the data that originated from bacterial physiological characterizations. This analysis allowed us to innovatively evaluate each strain as a whole and compare the performances of the strains under hypothetical scenarios of bacterial-trait requirements.

Enhancement of verticillium wilt resistance in tomato transplants by in vitro co-culture of seedlings with a plant growth promoting rhizobacterium (Pseudomonas sp. strain PsJN)

1998 ◽  
Vol 44 (6) ◽  
pp. 528-536 ◽  
Author(s):  
V K Sharma ◽  
J Nowak
Keyword(s):  
Plant Growth ◽  
Verticillium Wilt ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Disease Suppression ◽  
Pseudomonas Sp ◽  
Plant Growth Promoting ◽  
Growth Promoting

The potential utilization of a plant growth promoting rhizobacterium, Pseudomonas sp. strain PsJN, to enhance the resistance of tomato transplants to verticillium wilt was investigated. Plant growth and disease development were tested on the disease-susceptible cultivar Bonny Best after Verticillium dahliae infection of tissue culture plantlets bacterized in vitro (by co-culturing with the bacterium) and seedlings bacterized in vivo (after 3 weeks growth in the greenhouse). Significant differences in both disease suppression and plant growth were obtained between in vitro bacterized and nonbacterized (control) plants. The degree of protection afforded by in vitro bacterization depended on the inoculum density of V. dahliae; the best and worst protection occurred at the lowest (103 conidia ·mL-1) and highest (106 conidia ·mL-1) levels, respectively. In contrast, the in vivo bacterized tomatoes did not show plant growth promotion when compared to the nonbacterized control plants. When challenged with Verticillium, significant growth differences between in vivo bacterized plants (26.8% for shoot height) and nonbacterized controls were only seen at the 3rd week after inoculation. Compared with the in vitro inoculation, there was no delay in the verticillium wilt symptom expression, even at the lowest concentration of V. dahliae, by in vivo PsJN inoculation. These results suggest that endophytic colonization of tomato tissues is required for the Verticillium-resistance responses. Plant growth promotion preceeds the disease-resistance responses and may depend on the colonization thresholds and subsequent sensitization of hosts.Key words: Pseudomonas sp., plant growth promoting rhizobacterium, Verticillium dahliae, tomato, colonization, plant growth promotion, disease suppression.

scholarly journals Isolation and identification of plant growth promoting rhizobacteria from maize (Zea mays L.) rhizosphere and their plant growth promoting effect on rice (Oryza sativa L.)

2017 ◽  
Vol 57 (2) ◽  
pp. 144-151 ◽  
Author(s):  
Arun Karnwal
Keyword(s):  
Zea Mays ◽  
Plant Growth ◽  
Growth Promotion ◽  
Oryza Sativa L ◽  
Plant Growth Promoting Rhizobacteria ◽  
Promoting Effect ◽  
Isolation And Identification ◽  
Plant Growth Promoting ◽  
Growth Promoting

AbstractThe use of plant growth promoting rhizobacteria is increasing in agriculture and gives an appealing manner to replace chemical fertilizers, pesticides, and dietary supplements. The objective of our research was to access the plant growth promotion traits ofPseudomonas aeruginosa,P. fluorescensandBacillus subtilisisolated from the maize (Zea maysL.) rhizosphere.In vitrostudies showed that isolates have the potential to produce indole acetic acid (IAA), hydrogen cyanide, phosphate solubilisation, and siderophore. RNA analysis revealed that two isolates were 97% identical toP. aeruginosastrain DSM 50071 andP. aeruginosastrain NBRC 12689 (AK20 and AK31), while two others were 98% identical toP. fluorescensstrain ATCC 13525,P. fluorescensstrain IAM 12022 (AK18 and AK45) and one other was 99% identical toB. subtilisstrain NCDO 1769 (AK38). Our gnotobiotic study showed significant differences in plant growth variables under control and inoculated conditions. In the present research, it was observed that the isolated strains had good plant growth promoting effects on rice.

Microbial signaling and plant growth promotion

2014 ◽  
Vol 94 (6) ◽  
pp. 1051-1063 ◽  
Author(s):  
Fazli Mabood ◽  
Xiaomin Zhou ◽  
Donald L. Smith
Keyword(s):  
Plant Growth ◽  
Recent Work ◽  
Plant Growth Promotion ◽  
Environmental Conditions ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Disease Suppression ◽  
Plant Microbe Interaction ◽  
Plant Growth Promoting ◽  
Soil Microbial Population

Mabood, F., Zhou, X. and Smith, D. L. 2014. Microbial signaling and plant growth promotion. Can. J. Plant Sci. 94: 1051–1063. The rhizosphere offers a complex microhabitat where root exudates provide a diverse mixture of organic compounds that are used as nutrients or signals by the soil microbial population. On the other hand, these soil microorganisms produce compounds that directly or indirectly assist in plant growth promotion. The widely recognized mechanisms of plant growth promotion are biofertilization, production of phytohormones, suppression of diseases through biocontrol, induction of disease resistance and production of volatile signal compounds. During the past few decades our understanding of the interaction between rhizobacteria and plants has expanded enormously and this has resulted in application of microbial products used as crop inoculants (as biofertilizers), for increased crop biomass and disease suppression. However, this plant–microbe interaction is affected by adverse environmental conditions, and recent work has suggested that inoculants carrying plant-to-bacteria or bacteria-to-plant signals can overcome this and promote plant productivity under stressful environmental conditions. Very recent work has also shown that some plant growth-promoting rhizobacteria secrete novel signaling molecules that also promote plant growth. The use of rhizobacterial signaling in promoting plant growth offers a new window of opportunity, especially when we are looking at plants to provide biofuels and novel bioproducts. Developing technologies that can enhance plant growth and productivity is imperative.

scholarly journals Effects of two rhizobacteria inoculants on maize growth performance at different concentrations of glyphosate

2020 ◽  
Vol 37 (1) ◽  
pp. 21-37
Author(s):  
P.O. Akintokun ◽  
E. Ezaka ◽  
A.K. Akintokun ◽  
O.A. Oyedele
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Field Studies ◽  
Significant Difference ◽  
Plant Growth Promoting ◽  
Number Of Leaves ◽  
Growth Promoting ◽  
Screen House

The use of Rhizobacteria as biofertilizer is on the increase due to the ability of some of the bacteria to solubilize some insoluble essential nutrients in the soil and produce phytohormones necessary for plant growth. The effectiveness of two plant growth promoting rhizobacteria (Bacillus cereus and Pseudomonas aeruginosa) in plant growth promotion at different concentrations of glyphosate were evaluated. Some agronomic parameters such as plant height, size of girth, number of leaves on the screen house and field were measured and recorded. The results of the effects of P. aeruginosa on the height of maize at different concentrations showed that the plants inoculated with the isolates and planted on the soil without glyphosate (control) recorded the highest height on the 2nd (34.9 cm), 4th (52.45 cm), 6th (61.17 cm) and 8th (66.25 cm) weeks after planting, when compared to those planted on the soil spiked with different concentrations of glyphosate. The effects of the isolates on the size of girth of maize on the soil spiked with different concentrations of glyphosate showed the highest girth size on the soil inoculated with P. aeruginosa eight weeks after planting (8 WAP) with a girth size of 2.0cm and least at 14.4 mg/ml of glyphosate with a girth size of 1.2 cm at 8 weeks after planting. Similar trend was observed on the soil inoculated with B. cereus (without glyphosate) with the highest girth in the 2nd and 4th WAP (1.02 and 1.42 cm, respectively). The results of our field studies showed no significant difference (P≤0.05) in the height and number of leaves of the maize at different treatments and time (weeks after planting). Similar trend was observed i n the yield of maize. This study has shown that these isolates can be useful as biofertilizers especially in the absence or at low concentration of glyphosate. Keywords: Rhizobacteria, maize, Inoculants, Plant-growth-promotion.

scholarly journals Pathogen Biocontrol Using Plant Growth-Promoting Bacteria (PGPR): Role of Bacterial Diversity

2021 ◽  
Vol 9 (9) ◽  
pp. 1988
Author(s):  
Hao Wang ◽  
Runjin Liu ◽  
Ming Pei You ◽  
Martin J. Barbetti ◽  
Yinglong Chen
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Disease Suppression ◽  
Plant Growth Promoting Bacteria ◽  
Critical Determinant ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Plant Disease Management

A vast microbial community inhabits in the rhizosphere, among which, specialized bacteria known as Plant Growth-Promoting Rhizobacteria (PGPR) confer benefits to host plants including growth promotion and disease suppression. PGPR taxa vary in the ways whereby they curtail the negative effects of invading plant pathogens. However, a cumulative or synergistic effect does not always ensue when a bacterial consortium is used. In this review, we reassess the disease-suppressive mechanisms of PGPR and present explanations and illustrations for functional diversity and/or stability among PGPR taxa regarding these mechanisms. We also provide evidence of benefits when PGPR mixtures, rather than individuals, are used for protecting crops from various diseases, and underscore the critical determinant factors for successful use of PGPR mixtures. Then, we evaluate the challenges of and limitations to achieving the desired outcomes from strain/species-rich bacterial assemblages, particularly in relation to their role for plant disease management. In addition, towards locating additive or synergistic outcomes, we highlight why and how the benefits conferred need to be categorized and quantified when different strains/species of PGPR are used in combinations. Finally, we highlight the critical approaches needed for developing PGPR mixtures with improved efficacy and stability as biocontrols for utilization in agricultural fields.

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