This image illustrates the coloration of the fungi. They can also be hyaline glass-like, transparent , dark blue, or dark purple. Their conidiophores, the means through which F. Their macroconidia are fusiform, slightly curved, pointed at the tip, mostly three septate, basal cells pedicellate, x Microconidia are abundant, never in chains, mostly non-septate, ellipsoidal or cylindrical, straight or curved, x 2. Further information regarding the reproductive structures of F.
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Search Menu Abstract In vitro interaction of the pigeonpea wilt pathogen Fusarium udum and a biocontrol strain of Bacillus subtilis AF 1 showed that the fungus forms chlamydospore-like structures and increases vacuolation, when both cultures are simultaneously inoculated into potato dextrose broth.
The growth of F. Extracellular proteins of B. Cell-free filtrates of B. The formation of chlamydospore-like structures and vacuolated portions in mycelium of F. Biological control , Fusarium udum , Bacillus subtilis , Mycolysis 1 Introduction The bacteria that provide benefit to plants are of two general types, those that form a symbiotic relationship with the plant and those that are free-living in the soil, but are often found near, on, or even within the roots of plants.
While symbiotic bacteria have been studied extensively, the beneficial free-living soil bacteria have received attention only since the report of Kloepper and Schroth [ 1 ]. A number of different bacteria including bacilli have been considered to be PGPR [ 4 ]. Bacillus subtilis has been used for many years in attempts to control plant pathogens and increase plant growth. Seed treatments with B. A major mechanism involved in the biological control of plant pathogens is parasitism via degradation of the cell wall.
Chitinases which hydrolyse this polymer are produced by various organisms and have been implicated in the biocontrol process. Wilt disease caused by Fusarium udum is one of the most important soil-borne diseases of pigeonpea Cajanus cajan L Millsp.
The interaction of the biocontrol agent with the microbial community may provide clues to explain why many organisms suppress disease effectively in the laboratory but fail to do so in the field.
In the process of identifying the mechanism of action of AF 1, the present study is an attempt to look into the possible role of mycolysis in biological control of pigeonpea wilt. Pure culture of F. Synthetic medium pH 8. Lactophenol cotton blue was prepared with 0.
An equal volume of exponential-phase 6 h culture period AF 1 culture was inoculated into cultures of F. The experiment was run in triplicate and repeated two times. Microscopic observations were performed using a drop of mixed culture placed on a clean glass slide to which a drop of lactophenol blue was added. Photomicrographs were prepared using a Carl Zeiss photomicroscope.
The dry weight of the mixed culture and F. In ml of YEP medium supplemented with dextrose or dried mycelium of F. Triplicate flasks were inoculated and the experiment was repeated two times.
The pellet was dissolved in 10 mM sodium acetate buffer pH 4. The protein precipitate was dialysed against several changes of 10 mM sodium acetate buffer pH 4. Protein content of the supernatant was estimated according to the method of Bradford [ 14 ]. Protein precipitate from the culture filtrate of AF 1 at The absorbance of the wells loaded with the protein was recorded after a h interval. Control wells had no added protein but received a similar volume of the fungal spore suspension.
The experiment was run in triplicate and repeated twice. The supernatant was passed through 0. Before centrifugation, serially diluted cultures were plated on nutrient agar to monitor the cell numbers. The protein content was estimated as described by Bradford [ 14 ]. Chitinase assay was done with the cell-free filtrates according to Boller and Mauch [ 15 ], with minor modifications, using colloidal chitin as the substrate in 10 mM sodium phosphate buffer pH 7. Colloidal chitin was prepared using the procedure of Berger and Reynolds [ 16 ].
Colony-forming units were converted to their respective log units. When co-inoculation of AF 1 culture was at time 0, F. Co-inoculation of AF 1 after F. Co-inoculation did not affect conidiation. Inoculation of a h F. A: Control F. B: Interaction with B. An equal volume of 6 h grown B.
The growth of AF 1 on chitin medium was low when compared to dextrose and F.
Send correspondence to Z. E-mail: ym. Received Aug 6; Accepted Apr 1. This article has been cited by other articles in PMC. Abstract Crown disease CD is infecting oil palm in the early stages of the crop development. Previous studies showed that Fusarium species were commonly associated with CD.
Breeding for fusarium wilt resistance continues to be an integral part of genetic improvement of pigeonpea. A total of genotypes including germplasm and breeding lines were screened against wilt using wilt sick plot at Patancheru, India. Ninety two genotypes resistant to wilt were tested for a further two years using wilt sick plot at Patancheru. The genotype contributed
Search Menu Abstract In vitro interaction of the pigeonpea wilt pathogen Fusarium udum and a biocontrol strain of Bacillus subtilis AF 1 showed that the fungus forms chlamydospore-like structures and increases vacuolation, when both cultures are simultaneously inoculated into potato dextrose broth. The growth of F. Extracellular proteins of B. Cell-free filtrates of B. The formation of chlamydospore-like structures and vacuolated portions in mycelium of F.