Rigling D, Van Alfen N K
Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132.
J Bacteriol. 1991 Dec;173(24):8000-3. doi: 10.1128/jb.173.24.8000-8003.1991.
Transmissible hypovirulence of the chestnut blight fungus, Cryphonectria parasitica, is associated with cytoplasmic double-stranded-RNA (dsRNA) viruses. The fungal laccase has attracted interest because its activity is reduced in hypovirulent dsRNA-containing strains. A laccase cDNA clone was isolated by screening a cDNA expression library with antibodies against the purified extracellular laccase. The amino acid sequence deduced from part of the cDNA clone revealed high homology to other fungal laccases, especially to the Neurospora crassa laccase. A major laccase transcript 2.3 kb in length was detected in Northern (RNA) blots. In liquid culture, extracellular laccase activity was reduced by about 75% in the hypovirulent (dsRNA-free) strain EP155/2. In contrast, production of biomass was not affected by the dsRNA. Northern blot analysis indicated that dsRNA down regulates laccase biosynthesis by reducing laccase mRNA accumulation. The laccase gene is one of several developmentally regulated genes affected by the presence of dsRNA.
栗疫病菌（Cryphonectria parasitica）的可传播低毒力与细胞质双链RNA（dsRNA）病毒有关。真菌漆酶引起了人们的兴趣，因为其活性在含有低毒力dsRNA的菌株中会降低。通过用针对纯化的胞外漆酶的抗体筛选cDNA表达文库，分离出一个漆酶cDNA克隆。从部分cDNA克隆推导的氨基酸序列显示与其他真菌漆酶高度同源，尤其是与粗糙脉孢菌漆酶。在Northern（RNA）印迹中检测到一个长度为2.3 kb的主要漆酶转录本。在液体培养中，低毒力（无dsRNA）菌株EP155/2中的胞外漆酶活性降低了约75%。相比之下，生物量的产生不受dsRNA的影响。Northern印迹分析表明，dsRNA通过减少漆酶mRNA积累来下调漆酶生物合成。漆酶基因是受dsRNA存在影响的几个发育调控基因之一。
