Department of Wood Science, University of British Columbia, Vancouver, BC, Canada.
BMC Genomics. 2013 Jun 2;14:373. doi: 10.1186/1471-2164-14-373.
Ophiostoma piceae is a wood-staining fungus that grows in the sapwood of conifer logs and lumber. We sequenced its genome and analyzed its transcriptomes under a range of growth conditions. A comparison with the genome and transcriptomes of the mountain pine beetle-associated pathogen Grosmannia clavigera highlights differences between a pathogen that colonizes and kills living pine trees and a saprophyte that colonizes wood and the inner bark of dead trees.
We assembled a 33 Mbp genome in 45 scaffolds, and predicted approximately 8,884 genes. The genome size and gene content were similar to those of other ascomycetes. Despite having similar ecological niches, O. piceae and G. clavigera showed no large-scale synteny. We identified O. piceae genes involved in the biosynthesis of melanin, which causes wood discoloration and reduces the commercial value of wood products. We also identified genes and pathways involved in growth on simple carbon sources and in sapwood, O. piceae's natural substrate. Like the pathogen, the saprophyte is able to tolerate terpenes, which are a major class of pine tree defense compounds; unlike the pathogen, it cannot utilize monoterpenes as a carbon source.
This work makes available the second annotated genome of a softwood ophiostomatoid fungus, and suggests that O. piceae's tolerance to terpenes may be due in part to these chemicals being removed from the cells by an ABC transporter that is highly induced by terpenes. The data generated will provide the research community with resources for work on host-vector-fungus interactions for wood-inhabiting, beetle-associated saprophytes and pathogens.
Ophiostoma piceae 是一种在针叶原木和木材边材中生长的木质着色真菌。我们对其基因组进行了测序，并在一系列生长条件下分析了其转录组。与与山松甲虫相关的病原体 Grosmannia clavigera 的基因组和转录组进行比较，突出了定植并杀死活松树的病原体与定植并消耗死树的木材和内皮的腐生菌之间的差异。
我们将 33 Mbp 的基因组组装成 45 个支架，并预测了大约 8884 个基因。基因组大小和基因含量与其他子囊菌相似。尽管具有相似的生态位，但 O. piceae 和 G. clavigera 之间没有大规模的同线性。我们鉴定了参与黑色素生物合成的 O. piceae 基因，黑色素会导致木材变色并降低木制品的商业价值。我们还鉴定了参与简单碳源和边材生长的基因和途径，边材是 O. piceae 的天然基质。与病原体一样，腐生菌能够耐受萜类化合物，萜类化合物是松树防御化合物的主要类别；与病原体不同，它不能将单萜类化合物用作碳源。
这项工作提供了第二个软木 ophiostomatoid 真菌的注释基因组，并表明 O. piceae 对萜类化合物的耐受性可能部分归因于这些化学物质被一种 ABC 转运蛋白从细胞中去除，该转运蛋白被萜类化合物高度诱导。生成的数据将为研究木质生物、与甲虫相关的腐生菌和病原体的宿主-载体-真菌相互作用提供资源。
