Inhibition of Rust Diseases of Cereals by Metabolic Products of Verticillium chlamydosporium

Abstract

Verticillium chlamydosporium produced in submers culture several antifungal and/or phytotoxic compounds which were detected in a bioassay by using the pathogen‐host system Puccinia coronata and oat seedlings. The antifungal compounds were also tested against P. recondita on wheat and P. sorghi on corn seedlings. The production of the active metabolic compounds highly depended on the nutrient solution (peptone‐Czapek [PC] and malt extract [ME]) and on the fermentation times. Cell‐free filtrates of PC‐cultures of the fungus were highly phytotoxic; the fungitoxic and phytotoxic compounds were heat‐labile and dialyzable. The ethyl acetate extracts of the PC‐culture filtrates contained only the antifungal active substances. The antifungal compounds in ME‐culture filtrates proved to be heat‐stable, could be dialyzed and extracted with ethyl acetate. Ethyl acetate extracts of PC‐ and ME‐culture filtrates at concentrations of 500 μg/ml reduced rust disease incidence by up to 80 % compared to the control treatment. Further studies with extracts of ME‐culture filtrates displayed a distinct protective but no systemic activity. The extract interfered with the development of several infection structures of the rust fungi, mostly with the growth of germ tubes as well as with the formation of the aappressoria and haustorial mother cells. Three rust‐active fractions were obtained by preparative layer chromatography on silica gel. One of these fractions exhibited phytotoxic activity. The most active antifungal fraction is identical with the macrolid antibiotic monorden which caused a desorientated spiral growth in P. coronata germlings on oat leaves.

Colonisation of barley roots by endophytic Fusarium equiseti and Pochonia chlamydosporia: Effects on plant growth and disease

“…Pochonia chlamydosporia is a nematode eggparasitic fungus and occurs widely in cyst and root-knot nematode-infested soils around the world (Kerry, 1993). tritici (Leinhos & Buchenauer, 1992;Ehteshamul et al, 1994;Jacobs et al, 2003;Monfort et al, 2005). tritici (Leinhos & Buchenauer, 1992;Ehteshamul et al, 1994;Jacobs et al, 2003;Monfort et al, 2005).…”

“…Pochonia chlamydosporia also parasitizes economically important phytopathogenic fungi, including the take-all fungus Gaeumannomyces graminis var. tritici (Leinhos & Buchenauer, 1992;Ehteshamul et al, 1994;Jacobs et al, 2003;Monfort et al, 2005). All these properties make F. equiseti and P. chlamydosporia as potential biocontrol agents for both phytopathogenic fungi and plant parasitic nematodes.…”

Efficiency assessment of the antifungal metabolites from Sclerotium cepivorum against onion white rot disease

“…Hitherto, the use of microbial metabolites for the control of plant diseases has not been realized. Numerous reports have described possible applications of microbial metabolites in controlling plant pathogenic fungi and bacteria, for example, s e c o n d a r y m e t a b o l i t e s o f Ve r t i c i l l i u m chlamydosporium inhibited mycelial growth of Puccinia coronate, P. recondite and P. sorghi (Leinhos and Buchenauer 1992). Also, culture filtrate of Clitocybe nuda (an edible mushroom) was very effective in reducing the incidence of Phytophthora blight and leaf spot on pepper caused by Phytophthora capsici and Xanthomonas axonopodis pv.…”

Exploring Anastomosis of Hyphae and Mating-Type Compatibility of Pochonia chlamydosporia Isolates of the Meloidogyne, Heterodera and Globodera Biotypes

“…Among the clavicipitaceous nematophagous fungi, Pochonia chlamydosporia var. chlamydosporia is characterized by diversity of econutritional groups [2,3], acting as a soil saprotroph, an endophyte, an antagonist of phytopathogenic fungi [4,5], and a parasite of beetle larvae, mollusk eggs and PPN [6]. Pochonia chlamydosporia is also considered a successful BCA of PPN [7].…”