Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via G. Amendola 165/A, 70126 Bari, Italy.
Int J Food Microbiol. 2013 Jul 15;165(2):111-20. doi: 10.1016/j.ijfoodmicro.2013.04.024. Epub 2013 May 1.
Blue mould, caused by Penicillium expansum, is one of the most economically damaging postharvest diseases of pome fruits, although it may affect a wider host range, including sweet cherries and table grapes. Several reports on the role of mycotoxins in plant pathogenesis have been published, but few focussed on the influence of mycotoxins on the variation in host preference amongst producing fungi. In the present study the influence of the host on P. expansum pathogenicity/virulence was investigated, focussing mainly on the relationship with patulin production. Three P. expansum strain groups, originating from apples, sweet cherries, and table grapes (7 strains per host) were grown on their hosts of isolation and on artificial media derived from them. Strains within each P. expansum group proved to be more aggressive and produced more patulin than the other two groups under evaluation when grown on the host from which they originated. Table grape strains were the most aggressive (81% disease incidence) and strongest patulin producers (up to 554μg/g). The difference in aggressiveness amongst strains was appreciable only in the presence of a living host, suggesting that the complex pathogen-host interaction significantly influenced the ability of P. expansum to cause the disease. Incidence/severity of the disease and patulin production proved to be positively correlated, supporting the role of patulin as virulence/pathogenicity factor. The existence of genetic variation amongst isolates was confirmed by the High Resolution Melting method that was set up herein, which permitted discrimination of P. expansum from other species (P. chrysogenum and P. crustosum) and, within the same species, amongst the host of origin. Host effect on toxin production appeared to be exerted at a transcriptional level.
青霉扩展青霉引起的青霉病是果实采后最具经济破坏性的疾病之一，尽管它可能影响更广泛的宿主范围，包括甜樱桃和酿酒葡萄。已经发表了几篇关于真菌毒素在植物发病机制中的作用的报告，但很少有报告关注真菌毒素对产生真菌宿主偏好变化的影响。在本研究中，研究了宿主对扩展青霉致病性/毒力的影响，主要集中在产毒与产毒之间的关系上。从苹果、甜樱桃和酿酒葡萄中分离出的 3 个扩展青霉菌株组（每个宿主 7 株），在它们的分离宿主和从它们衍生的人工培养基上生长。在所评估的菌株中，每个扩展青霉组内的菌株在其起源的宿主上生长时，比其他两组更具侵略性，并产生更多的棒曲霉素。酿酒葡萄菌株的侵袭性最强（发病率 81%），棒曲霉素产量最高（达 554μg/g）。只有在存在活宿主的情况下，菌株间的侵袭力差异才明显，这表明复杂的病原体-宿主相互作用显著影响了扩展青霉引起疾病的能力。疾病的发病率/严重程度和棒曲霉素的产生呈正相关，这支持了棒曲霉素作为毒力/致病性因子的作用。通过建立的高分辨率熔解方法证实了分离株之间存在遗传变异，该方法允许区分扩展青霉和其他物种（产黄青霉和皱褶青霉），以及在同一物种中，区分其宿主来源。宿主对毒素产生的影响似乎是在转录水平上发挥的。
