School of Botany, The University of Melbourne, Victoria 3010, Australia.
Mol Plant Pathol. 2002 Nov 1;3(6):487-93. doi: 10.1046/j.1364-3703.2002.00144.x.
SUMMARY A gene (sp1) encoding a 12.3 kDa protein with a predicted secretion signal has been characterized from Leptosphaeria maculans, the dothideomycete that causes blackleg disease of canola (Brassica napus). This protein (SP1) contains four cysteine residues and shows a high sequence similarity to proteins from other ascomycetes. L. maculans sp1 has been placed on genetic and physical maps. This gene is expressed during the infection of B. napus cotyledons 10 days post-inoculation, coinciding with detection of the constitutively expressed fungal gene, beta-tubulin. L. maculans sp1, along with opsin and glyceraldehyde phosphate dehydrogenase, is light regulated. A recombinant SP1 protein expressed in Escherichia coli and a crude protein fraction secreted by L. maculans induced an autofluorescence response on B. napus leaves. The sp1 gene was mutated by targeted gene disruption whereby a hygromycin resistance gene was inserted. Such mutants caused similar-sized lesions on B. napus cotyledons as those caused by the wild-type isolate, indicating that sp1 is not crucial for pathogenicity of L. maculans on B. napus. This is the first report of disruption of this gene in any fungus.
摘要 从引起油菜黑胫病的长蠕孢菌（Leptosphaeria maculans）中鉴定了一个基因（sp1），该基因编码一种预测具有分泌信号的 12.3 kDa 蛋白。该蛋白（SP1）含有四个半胱氨酸残基，与其他子囊菌的蛋白质具有很高的序列相似性。L. maculans sp1 已被定位在遗传和物理图谱上。该基因在油菜子叶接种后 10 天的感染过程中表达，与组成型表达的真菌基因β-微管蛋白的检测时间一致。L. maculans sp1 与视蛋白和甘油醛磷酸脱氢酶一样受光照调控。在大肠杆菌中表达的重组 SP1 蛋白和由 L. maculans 分泌的粗蛋白部分在油菜叶片上诱导自发荧光反应。通过靶向基因敲除使 sp1 基因发生突变，在其中插入了潮霉素抗性基因。这样的突变体在油菜子叶上引起的病变与野生型分离株引起的病变大小相同，表明 sp1 对于 L. maculans 在油菜上的致病性不是至关重要的。这是首次报道在任何真菌中破坏该基因。
