ten Have A, Mulder W, Visser J, van Kan J A
Laboratory of Phytopathology, Graduate School of Experimental Plant Sciences, Wageningen Agricultural University, The Netherlands.
Mol Plant Microbe Interact. 1998 Oct;11(10):1009-16. doi: 10.1094/MPMI.1998.11.10.1009.
Botrytis cinerea, a fungus that causes diseases in over 200 plant species, secretes a number of endopolygalacturonases that have been suggested to be involved in pathogenesis. However, so far the corresponding genes have not been isolated from this fungus. We cloned Bcpg1, encoding endopolygalacturonase, with the pgaII gene from Aspergillus niger as a heterologous probe. The Bcpg1 gene is expressed to similar levels in liquid cultures of B. cinerea containing either 1% polygalacturonic acid or 1% sucrose, and is expressed during infection of tomato leaves. The Bcpg1 gene was eliminated by partial gene replacement, and the resulting mutants were tested for virulence on tomato leaves and fruits, as well as on apple fruits. Although the mutants were still pathogenic and displayed similar primary infections when compared with control strains, a significant decrease in secondary infection, i.e., growth of the lesion beyond the inoculation spot, was observed on all three host tissues. These results indicate that the Bcpg1 gene is required for full virulence.
灰葡萄孢是一种能使200多种植物致病的真菌，它分泌多种内切多聚半乳糖醛酸酶，这些酶被认为与致病过程有关。然而，到目前为止，尚未从这种真菌中分离出相应的基因。我们以黑曲霉的pgaII基因作为异源探针，克隆了编码内切多聚半乳糖醛酸酶的Bcpg1基因。Bcpg1基因在含有1%多聚半乳糖醛酸或1%蔗糖的灰葡萄孢液体培养物中表达水平相似，且在感染番茄叶片期间表达。通过部分基因替换消除了Bcpg1基因，并对所得突变体在番茄叶片和果实以及苹果果实上的毒力进行了测试。尽管与对照菌株相比，突变体仍具有致病性且表现出相似的初次感染，但在所有三种寄主组织上均观察到二次感染（即病斑在接种点以外的扩展）显著减少。这些结果表明，Bcpg1基因是完全致病力所必需的。
