Abstract
Adding compost to soil can result in plant disease suppression through the mechanisms of antagonistic action of compost microflora against plant pathogens. The aim of the study was to select effective antagonists of Pythium aphanidermatum from compost, to assess the effect of its extracellular metabolites on the plant pathogen, and to characterize antifungal metabolites. The fungal isolate selected by a confrontation test was identified as Aspergillus piperis A/5 on the basis of morphological features and the internal transcribed spacer (ITS) region, ?-tubulin and calmodulin partial sequences. Liquid chromatography-mass spectroscopy (LC-MS) analysis showed that gluconic and citric acid were the most abundant in the organic culture extract. However, the main antifungal activity was contained in the aqueous phase remaining after the organic solvent extraction. The presence of considerable amounts of proteins in both the crude culture extract as well as the aqueous phase remaining after solvent extraction was confirmed by SDS-PAGE. Isolated Aspergillus piperis A/5 exhibits strong antifungal activity against the phytopathogen Pythium aphanidermatum. It secretes a complex mixture of metabolites consisting of small molecules, including gluconic acid, citric acid and itaconic acid derivatives, but the most potent antifungal activity was associated with proteins resistant to heat and organic solvents. Our findings about the activity and characterization of antagonistic strain metabolites contribute to the understanding of the mechanism of interaction of antifungal metabolites as well as fungal-fungal interaction. The obtained results provide a basis for further application development in agriculture and food processing.
Highlights
Growing concerns regarding the sustainability requirements, environmental quality, human health and plant pathogen resistance to conventional pesticides have resulted in the need to find new approaches to plant protection [1,2]
Results of the confrontation test showed that the isolate A/5 produced the highest inhibition percentage of P. aphanidermatum (81%), and was chosen for further study (Fig. 1a)
Based on the most efficient antagonistic activity against P. aphanidermatum, as well as exhibited activity against other phytopathogens, the isolate A/5 was selected for further study
Summary
Growing concerns regarding the sustainability requirements, environmental quality, human health and plant pathogen resistance to conventional pesticides have resulted in the need to find new approaches to plant protection [1,2]. Pythium aphanidermatum is a widespread soil-borne plant pathogen and a member of the class Oomycetes [6]. It causes diseases in multiple plant species, leading to significant losses in agriculture [7]. P. aphanidermatum is susceptible to different biotic and abiotic factors during its saprophytic phase in soil [9]. Biotic factors include interactions with other microorganisms in soil, and P. aphanidermatum sensitivity to competition and antagonism may be the key potential for its biological control [4,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
