Efficacy, mechanism of action, molecular characterization and production methods: Different approaches to develop a biofungicide for postharvest disease control

Metschnikowia pulcherrima occurs naturally on fruits and floral parts of apple trees. A strain (MACH1) of M. pulcherrima was studied for its efficacy as biocontrol agent against Botrytis cinerea, Penicillium expansum and Alternaria alternata on apples stored for 8 months at 1 degree C, providing int...

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Bibliographic Details
Published in:Journal of plant pathology 2007-12, Vol.89 (3), p.S23-S23
Main Authors: Spadaro, D, Duraisamy, S, Annalisa, C, Garibaldi, A, Gullino, M L
Format: Article
Language:English
Subjects:
Alternaria alternata
Botrytis cinerea
Malus
Metschnikowia pulcherrima
Penicillium expansum
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Summary:Metschnikowia pulcherrima occurs naturally on fruits and floral parts of apple trees. A strain (MACH1) of M. pulcherrima was studied for its efficacy as biocontrol agent against Botrytis cinerea, Penicillium expansum and Alternaria alternata on apples stored for 8 months at 1 degree C, providing interesting results. The strain was investigated for its competition for iron against postharvest pathogens of apple. In vitro, in the coloured inhibition zone, B. cinerea and A. alternata conidia did not germinate and mycelial degeneration was observed. On apple, a high reduction of both pathogen growth was recorded when fruits were treated with M. pulcherrima. Further, production of cell wall degrading enzymes was investigated with positive results for chitinase and beta-1,3-glucanase activities. The enhanced activity of defence enzymes, such as peroxidase, polyphenoloxydase and phenylalanine ammo-nialyase, were measured in yeast-treated apples. To develop industrially another strain (BIO126) of M. pulcherrima, molecular characterization to track the microorganism was carried out and production and formulation protocols were developed. Amplified fragment length polymorphism (AFLP) patterns clearly distinguished 26 strains of M. pulcherrima, isolated from different substrates in different geographical regions. A concentration of 10 super(9) cfu/ml after 32 h fermentation was obtained in a substrate containing an organic nitrogen source and two carbon sources. Moreover, by adding several sugar solutions at different concentrations to the centrifuged yeast cell suspension, the best protective agent for freeze-drying was a 25% (v/v) maltose solution. No significant loss of viability on the formulated freeze-dried cells was recorded after 3 months of storage at 4 degree C.
ISSN:1125-4653