Antagonistic Mechanism of Fusarium Oxysporum of Soybean Root Rot by Bacillus Subtilis

2011 ◽  
Vol 108 ◽  
pp. 127-131
Author(s):  
Yong Gang Li ◽  
Feng Ming Ma

. Fusarium oxysporum is a soil-borne fungus that infects soybean roots and causes soybean root rot, a widespread and destructive soybean disease. The potential strain X6 belonged to Bacillus subtilis for controlling soybean root rot. And antagonistic mechanism of the pathogenic Fusarium oxysporum of soybean root rot by B. subtilis X6 was investigated. The antagonistic mechanism of strain X6 againt F. oxysporum can effectively inhibit mycelial growth, spores bearing and germination. After treated with metabolic product of strain X6, protoplast from the hyphae became abnormal. The activity effect of metabolic product of strain X6 was sensitive to temperature. So the study lay the groundwork for further research and application.

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1317-1323 ◽  
Author(s):  
J. X. Zhang ◽  
A. G. Xue ◽  
J. T. Tambong

Fusarium root rot is an important disease of soybean in Ontario, Canada. This study is to select antagonistic bacterial agents as effective alternatives to chemical pesticides for the control of root rots caused by Fusarium oxysporum and F. graminearum. Twenty-two Bacillus subtilis strains from soybean and corn roots were tested in dual cultures for inhibition of mycelial growth of F. oxysporum and F. graminearum. All strains significantly reduced mycelial growth of F. oxysporum by approximately 17 to 48% and of F. graminearum by 10 to 32%. Ten B. subtilis strains selected based on their larger fungal inhibition zones were evaluated against macroconidial germination. These strains inhibited the spore germination of F. oxysporum by 20 to 48% and of F. graminearum by 14 to 32% in cell-free filtrates. Under greenhouse conditions, the efficacy of seed and soil treatments with B. subtilis strains against the two Fusarium root rot pathogens was evaluated based on root rot severity, seedling emergence, plant height, and root dry weight. Six B. subtilis strains (SB01, SB04, SB23, SB24, SB28, and SB33) from soybean roots and two strains (CB01 and CH22) from corn roots significantly reduced the severity of the two Fusarium root rots in seed or soil treatments. Strains SB01, SB04, SB23, and SB24 were the most effective treatments against both pathogens in either seed or soil treatment. When applied as seed treatments, these four strains reduced root rot severity by 43 to 63% and increased emergence by 13 to 17%, plant height by 9 to 18%, and root dry weight by 8.4 to 19%. When used as soil treatments, they reduced root rot severity by 68 to 74% and increased emergence by 14 to 18%, plant height by 11 to 23%, and root dry weight by 16 to 24%. These results suggest that the novel strains of B. subtilis identified in this research can be effective alternatives to fungicides in managing Fusarium root rots of soybean, and a greater level of efficacy may be achieved when they were used as soil treatments than seed treatments.


2000 ◽  
Vol 46 (9) ◽  
pp. 809-816 ◽  
Author(s):  
G A Amer ◽  
R S Utkhede

The effect of various carrier formulations of Bacillus subtilis and Pseudomonas putida were tested on germination, growth, and yield of lettuce and cucumber crops in the presence of Pythium aphanidermatum and Fusarium oxysporum f.sp. cucurbitacearum, respectively. Survival of B. subtilis and P. putida in various carriers under refrigeration (about 0°C) and at room temperature (about 22°C) was also studied. In all carrier formulations, B. subtilis strain BACT-0 survived up to 45 days. After 45 days of storage at room temperature (about 22°C), populations B. subtilis strain BACT-0 were significantly higher in vermiculite, kaolin, and bacterial broth carriers compared with other carriers. Populations of P. putida were significantly higher in vermiculite, peat moss, wheat bran, and bacterial broth than in other carriers when stored either under refrigeration (about 0°C) or at room temperature (about 22°C) for 15 or 45 days. Germination of lettuce seed was not affected in vermiculite, talc, kaolin, and peat moss carriers, but germination was significantly reduced in alginate and bacterial broth carriers of B. subtilis compared to the non-treated control. Germination of cucumber seed was not affected by any of the carriers. Significantly higher fresh lettuce and root weights were observed in vermiculite and kaolin carriers of B. subtilis compared with P. aphanidermatum-inoculated control plants. Lettuce treated with vermiculite, and kaolin carriers of B. subtilis, or non-inoculated control lettuce plants had significantly lower root rot ratings than talc, peat moss, bacterial broth, and P. aphanidermatum-inoculated control plants. Growth and yield of cucumber plants were significantly higher in vermiculite-based carrier of P. putida than the other carriers and Fusarium oxysporum f.sp. cucurbitacearum-inoculated plants.Key words: Bacillus subtilis, Pseudomonas putida, Fusarium oxysporum f.sp. cucurbitacearum, Pythium aphanidermatum, talc, vermiculite, alginate, kaolin, peat moss, wheat bran, oat bran.


2016 ◽  
Vol 8 (1) ◽  
pp. 60-62 ◽  
Author(s):  
Ameer Junaithal Begum M. ◽  
P. Selvaraju ◽  
A. Vijayakumar

The purpose of the study was to determine the anti fungal activity of seaweed (Turbinaria conoides) extract against root rot pathogen Fusarium oxysporum. Seaweed extract was prepared from the species T. conoides collected from Rameswaram coastal area of Tamil Nadu during December was used for this study. Different concentrations of the extract viz., 5 %, 10 %, 15 % and 20 % was evaluated for their antifungal activity against F. oxysporum using poisoned food technique along with control and carbendazim (0.2 %) as check. No mycelial growth (0 cm) was observed in 15 % and 20 % sea weed extract weed extract treated plates even after 6 days ofincubation. Though the visible inhibition of mycelial growth was noticed in all the concentrations, the increased concentration of 15 and 20 % had shown 100 % inhibition. So, the lower concentration of 15 % can be best in controlling the F. oxysporum fungi. GC-MS analysis of seaweed extract showing the presence of several antimicrobial compounds in seaweeds may be the reason for such inhibition.


2006 ◽  
Vol 87 (1) ◽  
pp. 9-15
Author(s):  
Ricardo Ceballos ◽  
Graciela Palma ◽  
Fernando Perich ◽  
Fernando Pardo ◽  
Andrés Quiroz

Abstract Root rot caused by Fusarium oxysporum is a disease that reduces red clover persistence. Agronomical management of red clover includes MCPA application, and there is no information regarding the effects of this herbicide on the disease. MCPA was evaluated for its effects on F. oxysporum root rot and red clover (Trifolium pratense) growth in a greenhouse experiment. Additionally, in vitro mycelial growth and conidial germination of F. oxysporum were studied. For shoot dry weight and crown diameter of seedlings, the interaction of herbicide and inoculum was significant at 30 d. The herbicide–inoculum treatment reduced shoot dry weight by 20% at 1X rate and by 24% at 2X rate, and crown diameter was reduced by 10% at the high rate. The MCPA treatment caused a 40% reduction of root dry weight by the end of the experiment. Application of MCPA caused fusarium root rot to increase in severity on red clover seedlings and caused phytotoxicity at the high rate. Interaction with the other growth parameters was not significant, indicating that the effects of herbicide and inoculum were independent. Conidial germination and mycelial growth in vitro were reduced by MCPA. Results suggest that red clover growth could be negatively affected by F. oxysporum after MCPA application and that root rot severity increases at high rates of MCPA.


Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1254
Author(s):  
B. H. Lu ◽  
Z. Wang ◽  
G. J. Yi ◽  
G. W. Tan ◽  
F. Zeng ◽  
...  

2009 ◽  
Vol 27 (No. 3) ◽  
pp. 203-209 ◽  
Author(s):  
A. Šrobárová ◽  
Š. Eged ◽  
J. Teixeira Da Silva ◽  
A. Ritieni ◽  
A. Santini

Fusaric acid (FA) is one of the most important secondary metabolites produced by <I>Fusarium oxysporum</I> (Schlecht) (FO), <I>F. solani</I> (Mart.) Appel & Wollenweber, and <I>F. moniliforme</I> Sheldon. It is toxic to humans, many plants, and microorganisms and it enhances the toxicity of fumonisin and trichothecene. A simple and rapid method for fusaric acid (FA) screening in <I>Fusarium</I> isolates was developed. In this study, several strains of <I>Fusarium oxysporum</I> were tested for their ability to produce FA by using a suitable race of <I>Bacillus subtilis</I> as the bioassay. A modified method using small agar blocks with the fungus producing FA was applied in the screening test. FA standard and <I>F. culmorum</I> were used as controls. The experimental <I>F. oxysporum</I> isolates and FA standard produced transparent zones on the plates with <I>Bacillus subtilis</I>. The differences in size of the transparent zones corresponded to the quantity of FA when thin-layer chromatography was used.


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