Characterization of low temperature microorganisms inhabiting in moss in Polar Regions on species identification, enzyme production and cold resistance.

低温微生物特别是植物寄生真菌在物种鉴定、产酶和抗寒性等方面具有一定的特点。对2002年从斯匹次卑尔根岛分离的6株木霉进行了种类鉴定和产酶试验。所有菌株在培养条件下的形态和rDNA ITS区序列均被鉴定为多孢子木霉。对3株具有代表性的北极多孢霉进行了胞外酶生产试验。所有菌株在甜菜提取物液体培养基中分泌木聚糖酶和聚半乳糖醛酸酶。其中纯化了一种聚半乳糖醛酸酶（PG）。以德国产多孢T. polysporum菌株纯化的PG为对照。北极菌株PG在40℃时活性最佳，在0℃时活性为最大值的14 ~ 47%。德国菌株的PG在50℃时活性最佳，在0℃时活性为最大值的0 ~ 4%。结果表明，北极多孢T. pyium菌株可能是斯匹次卑尔根岛、格陵兰岛和乔治国王岛的冷活性T. pyium sp .的潜在来源。314株菌株属未知种1 ~ 5。在离体接种试验中，多数菌株对苔藓和小麦叶片具有致病性。在琼脂培养基上菌丝生长的最佳温度为22 ~ 28℃。至少有一种分离的北极Pythium菌株比其形态相关的Pythium菌株具有更大的抗冻性。这些结果表明，在极地地区居住的独特种类的蟒蛇。在此研究过程中，开发了从自然环境条件下分离它们的选择性培养基。在挪威斯瓦尔巴群岛的一种黑穗病真菌被鉴定为Microbotryum bistortarum。

Low temperature microorganisms especially plant parasitic fungi inhabiting in Polar Regions were characterized on species identification, enzyme production and cold resistance.Six Trichoderma strains isolated from Spitsbergen Island in 2002 were examined on species identification and enzyme production. The all strains were identified as Trichoderma polysporum by their morphology in a cultivation condition and sequences of rDNA ITS regions. Three representative strains of the Arctic T. polysporum were tested on production of extracellular enzymes. The all strains were secreted xylanase and polygalacturonase in a sugar beet extract liquid medium. Among these enzymes, a polygalacturonase (PG) was purified. The purified PG from T. polysporum strains isolated from Germany was used as comparison. PG from the Arctic strain showed optimum activity at 40℃ and 14 to 47% of maximum even at 0℃. While PG from the German strain showed optimum activity at 50℃ and 0 to 4% of maximum at 0℃. The results indicate that the Arctic T. polysporum strains are potential source of a cold active PG.Pythium spp. from Spitsbergen Island, Greenland and King George Island were examined on species identification. The total 314 isolates were categorized as unknown Pythium species 1 to 5. Most of them showed pathogenicity to a moss (Sanionia uncinata) and wheat leaves in an in vitro inoculation test. Their optimum temperatures for hyphal growth on an agar culture were 22 to 28℃. At least one isolate of Arctic Pythium strains has greater resistance to freezing than a strain of its morphologically related Pythium speices. These results suggest unique species of Pythium inhabiting in Polar Regions. During this investigation, Pythium selective media for isolation them from natural environmental conditions were developed.A smut fungus on Polygonum viviparum in Svalbard, Norway was identified as Microbotryum bistortarum during this study.