scholarly journals Activity of plant growth promoting rhizobacteria (PGPRs) in the biocontrol of tomato Fusarium wilt

2017 ◽  
Vol 53 (No. 2) ◽  
pp. 78-84 ◽  
Author(s):  
Boukerma Lamia ◽  
Benchabane Messaoud ◽  
Charif Ahmed ◽  
Khélif Lakhdar

The potential of Pseudomonas fluorescens PF15 and Pseudomonas putida PP27 to protect tomato plants against Fusarium wilt under greenhouse conditions was evaluated. In vitro antagonism showed a significant inhibition of the pathogen growth (47%) revealed by PF15. However, PP27 presented a 10% rate of the mycelium inhibition. An in situ experiment was conducted with split-root design for induced systemic resistance (ISR) and without split-root design to measure both ISR and antagonistic activities. Fluorescent Pseudomonas revealed a delay in the onset of symptoms and slower kinetics of disease progression compared to the pathogen control. McKinney’s index, which measures the severity of the disease, was reduced by 37–72%, and the levels of infection (incidence) by 7–36%.

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 579
Author(s):  
Carmen Sanjuana Delgado-Ramírez ◽  
Rufina Hernández-Martínez ◽  
Edgardo Sepúlveda

Plant growth-promoting rhizobacteria are often utilized to improve crop health and productivity. Nevertheless, their positive effects can be hindered if they fail to withstand the environmental and ecological conditions of the regions where they are applied. An alternative approach to circumvent this problem is a tailored selection of bacteria for specific agricultural systems. In this work, we evaluated the plant growth promoting and pathogen inhibition activity of rhizobacteria obtained from the rhizosphere of Mariola (Solanum hindsianum), an endemic shrub from Baja California. Eight strains were capable of inhibiting Fusarium oxysporum in vitro, and thirteen strains were found to possess three or more plant-growth-promotion traits. Molecular identification of these strains, using 16 s rRNA partial sequences, identified them as belonging to the genera Arthrobacter, Bacillus, Paenibacillus, Pseudomonas, and Streptomyces. Finally, the effect of selected plant growth-promoting rhizobacteria (PGPR) strains on the growth and suppression of Fusarium wilt in tomato was evaluated. Results showed that these strains improved tomato plants growth under greenhouse conditions and reduced Fusarium wilt effects, as reflected in several variables such as length and weight of roots and stem. This work highlights the potential of native plants related to regionally important crops as a valuable source of beneficial bacteria.


2013 ◽  
Vol 2 (3) ◽  
pp. 155-161 ◽  
Author(s):  
Avinash T. Shanthi ◽  
Ravishankar R. Vittal

Fusarium spp., are the major soil-borne as well as seed borne pathogens causing wilt and rot diseases in more than 80 plant species including cucurbits. Fusarium spp., causes up to 100 % yield loss in the worldwide. Eleven isolates including three standard isolates were tested both in-vitro and in-vivo. In-vitro assay was done by dual culture method. Maximum inhibition was in case of Fusarium solani by Bacillus cereus MIC5. Sarratia spp. MIC1 antagonized the F. verticillodes and F. solani2. P. aeruginosa MIC2 inhibits all tested isolates F. oxysporum1. P. aeruginosa MTCC2581 suppressed the radial growth rate of F. oxysporum2. The two systemic fungicides used were chlorothalonil + mefenoxam (1000 ppm) and carbendazim (75 ppm to 500 ppm) which checked the growth of F. oxysporum. Carbendazim was more effective compared to mefenoxam + chlorothalonil at all tested concentrations. The crude extract of P. aeruginosa MIC2 developed in chloroform: methanol (9:1) showed a metabolite at Rf - 0.77 which it may be 2,4- diacetylphloroglucinol (DAPG), a broad-spectrum antimicrobial agent. Increased cucurbit seeds germination and seedling vigour was observed in B. amyloliquefaciens MIC6 (68% 1576) and P. aeruginosa MTCC2581 (70% 1929) in primed seeds. Further P. aeruginosa MTCC2581 can be tested in the field against the Fusarium wilt.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 682
Author(s):  
Bruno Henrique Silva Dias ◽  
Sung-Hee Jung ◽  
Juliana Velasco de Castro Oliveira ◽  
Choong-Min Ryu

Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.


2017 ◽  
Vol 9 (1) ◽  
pp. 121-128
Author(s):  
S. Kumar ◽  
M. Singh ◽  
Sushil Sharma

The root rot disease in Jatropha curcas L. caused by Rhizoctonia. bataticola (Taub.) Butler has been recorded in causing 10-12 per cent mortality of 20-30 days old seedlings of Jatropha curcasin southern Haryana. The incidence of this disease has also been observed from other parts of Haryana too. Induction of systemic resistance in host plants through microbes and their bioactive metabolites are attaining popularity in modern agricultural practices. Studies on the plant growth-promoting rhizobacteria induced resistance in Jatropha curcas through phenyl propanoid metabolism against Rhizoctoniabataticola were undertaken at Chaudhary Charan Singh, Haryana Agricultural University, Regional Research Station, Bawal. Three plant growth-promoting rhizobacteria (PGPRs) viz., Pseudomonas maltophila, Pseudomonas fluorescens and Bacillus subtilis were evaluated for their potential to induce systemic resistance in Jatropha against root rot. The maximum increase of 97 per cent in total phenols, 120 per cent in peroxidase, 123 per cent in polyphenol oxidase, 101 per cent in phenylalanine ammonia lyase and 298 per cent in tyrosine ammonia lyase was detected in plants raised with Pseudomonas fluorescens+ Rhizoctoniaba-taticola inoculation in Jatropha curcas at 10 days post inoculation against control except total phenols where it was maximum (99%) at 30 DPI. There was slight or sharp decline in these parameters with age irrespective of inoculations. The pathogen challenged plants showed lower levels of total phenols and enzymes. The observations revealed that seed bacterization with Pseudomonas fluorescens results in accumulation of phenolics and battery of enzymes in response to pathogen infection and thereby induce resistance systemically.


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