scholarly journals Mixtures of Plant Growth-Promoting Rhizobacteria Enhance Biological Control of Multiple Cucumber Pathogens

1998 ◽  
Vol 88 (11) ◽  
pp. 1158-1164 ◽  
Author(s):  
Georg S. Raupach ◽  
Joseph W. Kloepper
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Leaf Spot ◽  
Plant Growth Promoting Rhizobacteria ◽  
Field Trials ◽  
Disease Suppression ◽  
Angular Leaf Spot ◽  
Systemic Resistance ◽  
Plant Growth Promoting ◽  
Growth Promoting

Plant growth-promoting rhizobacteria (PGPR) strains INR7 (Bacillus pumilus), GB03 (Bacillus subtilis), and ME1 (Curtobacterium flaccumfaciens) were tested singly and in combinations for biological control against multiple cucumber pathogens. Investigations under greenhouse conditions were conducted with three cucumber pathogens—Colletotrichum orbiculare (causing anthracnose), Pseudomonas syringae pv. lachrymans (causing angular leaf spot), and Erwinia tracheiphila(causing cucurbit wilt disease)—inoculated singly and in all possible combinations. There was a general trend across all experiments toward greater suppression and enhanced consistency against multiple cucumber pathogens using strain mixtures. The same three PGPR strains were evaluated as seed treatments in two field trials over two seasons, and two strains, IN26 (Burkholderia gladioli) and INR7 also were tested as foliar sprays in one of the trials. In the field trials, the efficacy of induced systemic resistance activity was determined against introduced cucumber pathogens naturally spread within plots through placement of infected plants into the field to provide the pathogen inoculum. PGPR-mediated disease suppression was observed against angular leaf spot in 1996 and against a mixed infection of angular leaf spot and anthracnose in 1997. The three-way mixture of PGPR strains (INR7 plus ME1 plus GB03) as a seed treatment showed intensive plant growth promotion and disease reduction to a level statistically equivalent to the synthetic elicitor Actigard applied as a spray.

scholarly journals Biocontrol of Cucumber Diseases in the Field by Plant Growth-Promoting Rhizobacteria With and Without Methyl Bromide Fumigation

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1073-1075 ◽  
Author(s):  
G. S. Raupach ◽  
J. W. Kloepper
Keyword(s):  
Plant Growth ◽  
Methyl Bromide ◽  
Leaf Spot ◽  
Plant Growth Promoting Rhizobacteria ◽  
Angular Leaf Spot ◽  
Systemic Resistance ◽  
Single Strain ◽  
Naturally Occurring ◽  
Plant Growth Promoting ◽  
Growth Promoting

Field trials were conducted in 1996 and 1997 to determine the effect of plant growth-promoting rhizobacteria (PGPR) strains, which previously were found to induce systemic resistance in cucumber, on cucumber plant growth and on naturally occurring cucumber diseases with and without methyl bromide fumigation. Seven PGPR seed treatments included single-strain treatments and mixtures of Bacillus pumilus strain INR7, Curtobacterium flaccumfaciens strain ME1, and Bacillus subtilis strain GB03. In both years, in the absence of methyl bromide, all seven PGPR treatments significantly promoted plant growth, compared to the non-treated control, while with methyl bromide fumigation, only 3 and 1 of the same PGPR treatments promoted growth significantly in 1996 and 1997, respectively. In 1996, main runner length of plants in all seven PGPR treatments without fumigation was statistically equivalent to the main runner length of the nontreated control with methyl bromide fumigation. Naturally occurring foliar diseases were angular leaf spot, caused by Pseudomonas syringae pv. lachrymans in 1996, and a mixed infestation of angular leaf spot and anthracnose, caused by Colletotrichum orbiculare in 1997. In both years, all PGPR treatments significantly reduced severity of foliar disease, compared to the nontreated control, with and without methyl bromide. Mixtures of PGPR strains showed a higher level of disease protection in both years with and without methyl bromide. The results indicate that attempts to develop PGPR-mediated induced systemic resistance into components of vegetable integrated pest management should not be negatively impacted by the planned withdraw of MeBr from standard vegetable production and that PGPR may help compensate for reduced plant growth often seen without methyl bromide fumigation.

scholarly journals Amendment of Muskmelon and Watermelon Transplant Media with Plant Growth-Promoting Rhizobacteria: Effects on Seedling Quality, Disease, and Nematode Resistance

2003 ◽  
Vol 13 (3) ◽  
pp. 476-482 ◽  
Author(s):  
Nancy Kokalis-Burelle ◽  
C.S. Vavrina ◽  
M.S. Reddy ◽  
J.W. Kloepper
Keyword(s):  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Citrullus Lanatus ◽  
Plant Growth Promoting Rhizobacteria ◽  
Angular Leaf Spot ◽  
Root Weight ◽  
Didymella Bryoniae ◽  
Plant Growth Promoting ◽  
Growth Promoting

Greenhouse and field trials were performed on muskmelon (Cucumis melo) and watermelon (Citrullus lanatus) to evaluate the effects of six formulations of plant growth-promoting rhizobacteria (PGPR) that have previously been shown to increase seedling growth and induce disease resistance on other transplanted vegetables. Formulations of Gram-positive bacterial strains were added to a soilless, peat-based transplant medium before seeding. Several PGPR treatments significantly increased shoot weight, shoot length, and stem diameter of muskmelon and watermelon seedlings and transplants. Root weight of muskmelon seedlings was also increased by PGPR treatment. On watermelon, four PGPR treatments reduced angular leaf spot lesions caused by Pseudomonas syringae pv. lachrymans, and gummy stem blight, caused by Didymella bryoniae, compared to the nontreated and formulation carrier controls. One PGPR treatment reduced angular leaf spot lesions on muskmelon compared to the nontreated and carrier controls. On muskmelon in the field, one PGPR treatment reduced root-knot nematode (Meloidogyne incognita) disease severity compared to all control treatments.

scholarly journals Current Utility of Plant Growth-Promoting Rhizobacteria as Biological Control Agents towards Plant-Parasitic Nematodes

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1167
Author(s):  
Pratima Subedi ◽  
Kaitlin Gattoni ◽  
Wenshan Liu ◽  
Kathy S. Lawrence ◽  
Sang-Wook Park
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Parasitic Nematodes ◽  
Biological Control Agents ◽  
Plant Parasitic Nematodes ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Plant Parasitic

Plant-parasitic nematodes (PPN) are among the most economically and ecologically damaging pests, causing severe losses of crop production worldwide. Chemical-based nematicides have been widely used, but these may have adverse effects on human health and the environment. Hence, biological control agents (BCAs) have become an alternative option for controlling PPN, since they are environmentally friendly and cost effective. Lately, a major effort has been made to evaluate the potential of a commercial grade strain of plant growth-promoting rhizobacteria (PGPR) as BCAs, because emerging evidence has shown that PGPR can reduce PPN in infested plants through direct and/or indirect antagonistic mechanisms. Direct antagonism occurs by predation, release of antinematicidal metabolites and semiochemicals, competition for nutrients, and niche exclusion. However, the results of direct antagonism may be inconsistent due to unknown endogenous and exogenous factors that may prevent PGPR from colonizing plant’s roots. On the other hand, indirect antagonism may occur from the induced systemic resistance (ISR) that primes whole plants to better fight against various biotic and abiotic constraints, actuating faster and/or stronger defense responses (adaption), enhancing their promise as BCAs. Hence, this review will briefly revisit (i) two modes of PGPR in managing PPN, and (ii) the current working models and many benefits of ISR, in the aim of reassessing current progresses and future directions for isolating more effective BCAs and/or developing better PPN management strategy.

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 Biological Control of Meloidogyne incognita by Spore-forming Plant Growth-promoting Rhizobacteria on Cotton

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 774-784 ◽  
Author(s):  
Ni Xiang ◽  
Kathy S. Lawrence ◽  
Joseph W. Kloepper ◽  
Patricia A. Donald ◽  
John A. McInroy ◽  
...  
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Meloidogyne Incognita ◽  
Plant Growth Promoting Rhizobacteria ◽  
Field Trials ◽  
Parasitic Nematodes ◽  
Subtilis Strain ◽  
Plant Growth Promoting ◽  
Growth Promoting

In the past decade, increased attention has been placed on biological control of plant-parasitic nematodes using various fungi and bacteria. The objectives of this study were to evaluate the potential of 662 plant growth-promoting rhizobacteria (PGPR) strains for mortality to Meloidogyne incognita J2 in vitro and for nematode management in greenhouse, microplot, and field trials. Results indicated that the mortality of M. incognita J2 by the PGPR strains ranged from 0 to 100% with an average of 39%. Among the PGPR strains examined, 212 of 662 strains (or 33%) caused significantly greater mortality percent of M. incognita J2 than the untreated control. Bacillus was the major genus initiating a greater mortality percentage when compared with the other genera. In subsequent trials, B. velezensis strain Bve2 reduced M. incognita eggs per gram of cotton root in the greenhouse trials at 45 days after planting (DAP) similarly to the commercial standards Abamectin and Clothianidin plus B. firmus I-1582. Bacillus mojavensis strain Bmo3, B. velezensis strain Bve2, B. subtilis subsp. subtilis strain Bsssu3, and the Mixture 2 (Abamectin + Bve2 + B. altitudinis strain Bal13) suppressed M. incognita eggs per gram of root in the microplot at 45 DAP. Bacillus velezensis strains Bve2 and Bve12 also increased seed-cotton yield in the microplot and field trials. Overall, results indicate that B. velezensis strains Bve2 and Bve12, B. mojavensis strain Bmo3, and Mixture 2 have potential to reduce M. incognita population density and to enhance growth of cotton when applied as in-furrow sprays at planting.

Molecular imaging of plant-microbe interactions on the Brachypodium seed surface

The Analyst ◽  
2021 ◽  
Author(s):  
Yuchen Zhang ◽  
Rachel Komorek ◽  
Jiyoung Son ◽  
Shawn Riechers ◽  
Zihua Zhu ◽  
...  
Keyword(s):  
Biological Control ◽  
Molecular Imaging ◽  
Plant Growth ◽  
Crucial Role ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Tissues ◽  
Seed Surface ◽  
Plant Growth Promoting ◽  
Microbe Interactions ◽  
Growth Promoting

Plant growth-promoting rhizobacteria (PGPR) play a crucial role in biological control and pathogenic defense on and within plant tissues, however the mechanism(s) by which plants associate with PGPR to elicit...

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