Bencheqroun S Krimi, Bajji M, Massart S, Bentata F, Labhilili M, Achbani H, El Jaafari S, Jijakli M H
Unit: de Phytopathologie, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés 2, BE-5030 Gembloux, Belgium.
Commun Agric Appl Biol Sci. 2006;71(3 Pt B):1151-7.
Aureobasidium pullulans strain Ach1-1 was recently isolated for its biocontrol effectiveness against Penicillium expansum, the causal agent of blue mold on harvested apples. In the present study, strain Ach1-1 was found to be very effective in controlling P. expansum on apple wounds. For in vitro tests, strain Ach1-1 and P. expansum were cocultured in the presence of apple juice (0 - 5%) using a system preventing direct contact between both agents. The presence of the antagonist greatly reduced germination of conidia at low (0.1, 0.5 and 1%) but not at high (5%) juice concentrations. Germination of previously inhibited conidia at 0.5% apple juice was partially restored in the presence of the antagonist when fresh juice was added at a final concentration of 5%, and completely recovered at both 0.5 and 5% juice concentrations in the absence of the antagonist. These data show that P. expansum conidia are able to germinate when cocultered with strain Ach1-1 in conditions of sufficient rather than limited nutrient availability and that the antagonist does not affect the viability of these conidia, indicating that the inhibitory effect of strain Ach1-1 on conidia germination may be due to a competition for nutrients. Such observation was confirmed in situ since the application of high amounts of exogenous amino acids, vitamins or sugars on apple wounds significantly reduced the protective level of strain Ach1-1 against P. expansum, the most important effect was obtained with amino acids followed by vitamins and then by sugars. The present work provides both in vitro and in situ evidence that the biocontrol activity of strain Ach1-1 against P. expansum essentially relies on competition for apple fruit nutrients, especially amino acids.
最近分离出了出芽短梗霉菌株Ach1-1，因其对扩展青霉具有生物防治效果，扩展青霉是采后苹果青霉病的病原菌。在本研究中，发现菌株Ach1-1在控制苹果伤口上的扩展青霉方面非常有效。对于体外试验，使用防止两种菌直接接触的系统，将菌株Ach1-1和扩展青霉在苹果汁（0 - 5%）存在的情况下共培养。在低果汁浓度（0.1%、0.5%和1%）下，拮抗菌的存在显著降低了分生孢子的萌发，但在高果汁浓度（5%）下则没有。当最终浓度为5%的新鲜果汁添加时，在拮抗菌存在的情况下，先前在0.5%苹果汁中受到抑制的分生孢子的萌发部分恢复，并且在没有拮抗菌的情况下，在0.5%和5%的果汁浓度下完全恢复。这些数据表明，在营养充足而非有限的条件下，扩展青霉分生孢子与菌株Ach1-1共培养时能够萌发，并且拮抗菌不影响这些分生孢子的活力，这表明菌株Ach1-1对分生孢子萌发的抑制作用可能是由于对营养物质的竞争。这种观察在原位得到了证实，因为在苹果伤口上施用大量外源氨基酸、维生素或糖显著降低了菌株Ach1-1对扩展青霉的保护水平，其中氨基酸的影响最大，其次是维生素，然后是糖。目前的工作提供了体外和原位证据，表明菌株Ach1-1对扩展青霉的生物防治活性主要依赖于对苹果果实营养物质的竞争，尤其是氨基酸。
