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

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.

1998 ◽  
Vol 88 (11) ◽  
pp. 1158-1164 ◽  
Author(s):  
Georg S. Raupach ◽  
Joseph W. Kloepper

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.


Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1073-1075 ◽  
Author(s):  
G. S. Raupach ◽  
J. W. Kloepper

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.


2005 ◽  
Vol 18 (5) ◽  
pp. 385-396 ◽  
Author(s):  
Yanqing Wang ◽  
Yumiko Ohara ◽  
Hitoshi Nakayashiki ◽  
Yukio Tosa ◽  
Shigeyuki Mayama

Pseudomonasz fluorescens FPT9601-T5 was originally identified as an endophytic plant growth-promoting rhizobacteria (PGPR) on tomato. To perform a molecular dissecttion of physiological and biochemical changes occurring in the host triggered by P. fluorescens FPT9601-T5 colonization, the model plant Arabidopsis was used in this study. Root colonization of Arabidopsis with P. fluorescens FPT9601-T5 promoted plant growth later than three weeks after inoculation and partially suppressed disease symptoms caused by Pseudomonas syringae pv. tomato DC3000, indicating that P. fluorescens FPT9601-T5 acted as a PGPR on Arabidopsis. To obtain a global view on transcript modification during the Arabidopsis-FPT9601-T5 interaction, we performed microarray analysis using Affymetrix Genechip probe arrays representing approximately 22,800 genes. The results showed that 95 and 105 genes were up- or down-regulated, respectively, more than twofold in FPT9601-T5-treated Arabidopsis plants as compared with control plants. Those up-regulated included genes involved in metabolism, signal transduction, and stress response. Noteworthy, upon FPT9601-T5 colonization, putative auxin-regulated genes and nodulin-like genes were up-regulated, and some ethylene-responsive genes were down-regulated. Our results suggest that P.fluorescens FPT9601-T5 triggered plant responses in a manner similar to known PGPR and, at least in some aspects, to rhizobia.


2007 ◽  
Vol 55 (2) ◽  
pp. 243-249 ◽  
Author(s):  
S. Lokesh ◽  
B. Bharath ◽  
V. Raghavendra ◽  
M. Govindappa

In the present study, seven isolates of plant growth-promoting rhizobacteria were used for seed treatment to suppress seedling diseases caused by fungi. Their effect on the seed germination and seedling vigour of watermelon was also studied. Among them INR-7 was able to inhibit a broad range of fungal species, GBO3 and IPC-11 were found to be effective against Fusarium spp. and Didymella bryoniae , while isolates SE-34 and T-4 were effective against Myrothecium species and also reduced the development of symptoms on the seedlings. Isolates GBO3, IPC-11 and INR-7 increased seed germination and seedling vigour to the greatest extent.


2019 ◽  
Vol 50 (3) ◽  
pp. 181-190
Author(s):  
A.K. Akintokun ◽  
E. Ezaka ◽  
P.O. Akintokun ◽  
O.B. Shittu ◽  
L. B. Taiwo

Abstract The use of plant growth promoting rhizobacteria (PGPR) as biofertilizer is a relatively safer, environment friendly and cost effective. This work was designed to assess plant growth promoting abilities of rhizobacteria and evaluate their effect on germination and growth of maize. The bacteria were isolated and screened for plant growth promoting abilities using Pikovskaya agar, Aleksandrov agar and Jensen media. Twelve isolates that showed multiple attributes were further screened for indole acetic acid (IAA) and gibberellic acid (GA) production; best five isolates were selected for further studies. The results of IAA and GA production showed a considerable amount of IAA and GA produced by the isolates which ranged between 9–94 and 21–97 mg l–1, respectively. The selected isolates identified as Bacillusmojavensis, Pseudomonas aeruginosa, Alcaligenes faecalis, Pseudomonas syringae and Bacillus cereus showed a significant difference(P≤0.05) in the amount of potassium(K) and phosphorus(P) solubilized at different source of K (KCl and mica powder) and P (Ca2PO4 and rock phosphate). The isolates also recorded significant level of nitrogen fixing ability with Alcaligenes faecalis strain P156 fixing the highest amount of nitrogen (11.4 mg N fixed per l) and least by Bacillus mojavensis strain NBSL51 (6.3 mg N fixed per l).The results of plant inoculation test showed that Bacillus cereus strain 20UPMNR significantly enhanced the root and shoot dry weight. All the selected isolates enhanced shoot and root length except Bacillus mojavensis which produced less effect on root length when compared to the control. These results have provided vital information for the development of a bio fertilizer for maize.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Nadège A. Agbodjato ◽  
Pacôme A. Noumavo ◽  
Adolphe Adjanohoun ◽  
Léonce Agbessi ◽  
Lamine Baba-Moussa

This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR) and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the control, P. putida has significantly improved root weight (44.84%) and germinated seed weight (31.39%) whereas chitosan-P. putida has increased the shoot weight (65.67%). For the growth test, the maximal heights (17.66%) were obtained by plants treated with the combination A. lipoferum-P. fluorescens-P. putida. Chitosan-P. fluorescens induced the highest increases of leaves per plant (50.09%), aerial (84.66%), and underground biomass (108.77%) production. The plants inoculated with A. lipoferum had the large leaf areas with an increase of 54.08%, while combinations P. fluorescens-P. putida and chitosan-A. lipoferum improved the aerial and underground dry matter of plants to 26.35% and 18.18%. The nitrogen content of the plants was increased by chitosan-A. lipoferum-P. fluorescens-P. putida with an increasing of 41.61%. The combination of chitosan and PGPR can be used as biological fertilizers to increase maize production.


Author(s):  
Domenico Prisa ◽  
Alessandra Benati

The aim of this work was to use Plant growth promoting rhizobacteria (PGPR) for the improvement of cultivation and agronomic and pathogen protection characteristics of ornamental bulbous plants such as Tulip (fam. Liliacee), Iris (fam. Iridacee), Freesia (fam. Iridacee) and Narcissus (fam. Amarillidacee). The experiments, started in November 2020, were conducted in the greenhouses of CREA-OF in Pescia (Pt), Tuscany, Italy. The experimental groups were: i) group control irrigated with water and substrate previously fertilized; ii) group with Effective microorganisms irrigated with water and substrate previously fertilized; iii) group with beneficial bacteria (TNC Bactorrs13) irrigated with water and substrate previously fertilized; iv) group with beneficial bacteria (Tarantula powder Advanced nutrients ) irrigated with water and substrate previously fertilized. The trial showed a significant improvement in the agronomic parameters analysed on plants obtained from Narcissus, Iris, Tulip and Freesia bulbs treated with microorganisms. In particular, there was an increase in plant height, vegetative and root weight, bulb weight and diameter, and flower duration. In addition, the use of microorganisms in the growing medium showed a significant increase in the biocontrol of Botrytis cinerea. The treatment with Effective microorganisms (EM) showed the most significant results for all agronomic parameters analysed. The improvement in plant growth brought about by the activity of bacteria is a key aspect of achieving sustainable agricultural goals in the future. More research is needed in this field to identify new soil microbial strains that can be used for the formulation of new products applicable for improving the quality and resistance to biotic and abiotic stresses of potted plants. KEY-WORDS: Ornamental bulbs; Microorganisms; Sustainable agriculture; Flowers; Pot plants


2008 ◽  
Vol 98 (6) ◽  
pp. 666-672 ◽  
Author(s):  
J. Barriuso ◽  
B. Ramos Solano ◽  
F. J. Gutiérrez Mañero

The ability of four plant growth-promoting rhizobacteria, isolated in a previous study, to induce systemic resistance on Arabidopsis thaliana Col 0 against biotic and abiotic stress was evaluated. All the bacteria enhanced protection against the foliar pathogen Pseudomonas syringae DC3000 and increased plant tolerance to salt stress (NaCl 60 mM). Bacillus sp. strain L81 and Arthrobacter oxidans strain BB1 performed best with a decrease in the disease index of 61.2 and 52.3%, respectively, and a reduction in the mortality due to salt stress of 72.4 and 57.8%, respectively. Additionally, significant differences were found in growth and photosynthesis, again, L81 and BB1 performed best either in normal or under stress conditions. In order to elucidate the pathway elicited by these two strains to induce systemic resistance, experiments with the transgenic line of Arabidopsis thaliana NahG (defective in salicylic acid [SA]) and with the jar1 mutant (defective in jasmonic acid) were carried out. Results showed that the SA-dependent pathway was involved in the defense response induced by strains L81 and BB1. Results from quantitative reverse transcription-polymerase chain reaction analysis of the PR1 gene, related to the SA-dependent pathway and the PDF1.2 gene related to the SA-independent pathway, showed an increased expression of PR1 in BB1-treated plants, confirming involvement of the SA-dependent pathway in the defensive response.


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