Abstract
D-galacturonic acid (GalA) is the major component of pectin, which can be degraded by saprotrophic and pathogenic fungi; GalA potentially is an important carbon source for microorganisms living on decaying plant material. A GalA catabolic pathway was proposed in filamentous fungi, comprising three enzymatic steps, involving D-galacturonate reductase, L-galactonate dehydratase, and 2-keto-3-deoxy-L-galactonate aldolase. The Botrytis cinerea genome contains two non-homologous galacturonate reductase genes (Bcgar1 and Bcgar2), a dehydratase gene (Bcgdh1), and an aldolase gene (Bckdga1). The four proteins were expressed in E. coli and enzymatic activity was confirmed. Targeted gene replacement of all four genes, either separately or in combinations, yielded mutants that were unable to grow on GalA as the sole carbon source. Mutants were also unable to grow on pectin or pectate, in spite of their ability to decompose the polymer by secreted pectinases. The mutants showed similar virulence as the wild-type strain on tomato leaves,
apple fruit and bell pepper, whereas virulence was reduced on Nicotiana benthamiana and Nicotiana tabacum leaves. The results indicate that GalA serves as a very important carbon source for B. cinerea growth during infection on Nicotiana species, but not other plant tissues
Original language | English |
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Title of host publication | Book of Abstracts 26th Fungal Genetics Conference, Asilomar, Pacific Grove, California, USA, 15-20 March 2011 |
Pages | 196 |
Publication status | Published - 2011 |
Event | 26th Fungal Genetics Conference, Asilomar, Pacific Grove, California, USA - Duration: 15 Mar 2011 → 20 Mar 2011 |
Conference/symposium
Conference/symposium | 26th Fungal Genetics Conference, Asilomar, Pacific Grove, California, USA |
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Period | 15/03/11 → 20/03/11 |