Publication Type: | Journal Article |
Year of Publication: | 2010 |
Authors: | Ajouz, S, Nicot, PC, Bardin, M |
Journal: | Plant Pathology |
Volume: | 59 |
Issue: | 3 |
Date Published: | 2010 |
ISBN Number: | 1365-3059 |
Keywords: | Biological control, durability, experimental evolution, fitness, Resistance, selection |
Abstract: | The objective of this work was to estimate the risk of a decrease in the efficacy of biocontrol as a result of selection pressure exerted by biocontrol agents on Botrytis cinerea, focusing on pyrrolnitrin, an antibiotic identified in diverse biocontrol agents having an effect on B. cinerea. To evaluate a possible decrease in sensitivity to pyrrolnitrin, 10 successive generations of five isolates of B. cinerea were produced in vitro in the presence of a sublethal dose (10 μg L−1) of the antibiotic. For one isolate, a significant reduction in the sensitivity to pyrrolnitrin at the fifth generation was observed with a resistance factor of c. 11. The production of 10 additional generations for four of these isolates, with increasing doses of pyrrolnitrin (100–4000 μg L−1), resulted in the development of variants of B. cinerea with high levels of resistance to the antibiotic (RF > 1000) and a reduced sensitivity in vitro to a pyrrolnitrin-producing bacterium. Reverse adaptation of resistant variants after 10 additional generations in the absence of selection pressure was not observed, suggesting stability of the resistance. Comparison of the pyrrolnitrin-resistant generations and their sensitive parental isolates for mycelial growth, sporulation and aggressiveness on plant tissues revealed that the high level of resistance to pyrrolnitrin resulted in a high fitness cost. Mycelial growth was reduced between 1·7 to 3·6 times and sporulation reduced 3·8 to 6·6 times that of sensitive parental isolates. Similarly, aggressiveness was 7 to 10 and 3 to 10 times lower for resistant isolates on tomato and apple, respectively. This study provides evidence that a fungal plant pathogen is able to gradually build up resistance to an antibiotic produced by a biocontrol agent. |
URL: | http://dx.doi.org/10.1111/j.1365-3059.2009.02230.x |
Short Title: | Plant Pathology |