Wang Yi, Wang Juan, Cheong Yong Hwa, Hur Jae-Seoun
Laboratory of Forest Plant Cultivation and Utilization, Yunnan Academy of Forestry, Kunming 650-204, China.
Korean Lichen Research Institute, Sunchon National University, Suncheon 540-742, Korea.
Mycobiology. 2014 Mar;42(1):34-40. doi: 10.5941/MYCO.2014.42.1.34. Epub 2014 Mar 31.
Usnea longissima has a long history of use as a traditional medicine. Several bioactive compounds, primarily belonging to the polyketide family, have been isolated from U. longissima. However, the genes for the biosynthesis of these compounds are yet to be identified. In the present study, three different types of non-reducing polyketide synthases (UlPKS2, UlPKS4, and UlPKS6) were identified from a cultured lichen-forming fungus of U. longissima. Phylogenetic analysis of product template domains showed that UlPKS2 and UlPKS4 belong to group IV, which includes the non-reducing polyketide synthases with an methyltransferase (MeT) domain that are involved in methylorcinol-based compound synthesis; UlPKS6 was found to belong to group I, which includes the non-reducing polyketide synthases that synthesize single aromatic ring polyketides, such as orsellinic acid. Reverse transcriptase-PCR analysis demonstrated that UlPKS2 and UlPKS4 were upregulated by sucrose; UlPKS6 was downregulated by asparagine, glycine, and alanine.
长松萝作为传统药物已有悠久的使用历史。几种主要属于聚酮化合物家族的生物活性化合物已从长松萝中分离出来。然而，这些化合物生物合成的基因尚未被鉴定。在本研究中，从长松萝的一种培养地衣形成真菌中鉴定出三种不同类型的非还原聚酮合酶（UlPKS2、UlPKS4和UlPKS6）。产物模板结构域的系统发育分析表明，UlPKS2和UlPKS4属于第四组，该组包括具有参与基于甲基苔色醇的化合物合成的甲基转移酶（MeT）结构域的非还原聚酮合酶；发现UlPKS6属于第一组，该组包括合成单芳环聚酮化合物（如苔色酸）的非还原聚酮合酶。逆转录酶 - PCR分析表明，UlPKS2和UlPKS4被蔗糖上调；UlPKS6被天冬酰胺、甘氨酸和丙氨酸下调。
