Turk Martina, Gostinčar Cene
Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia.
Fungal Biol. 2018 Jan;122(1):63-73. doi: 10.1016/j.funbio.2017.10.005. Epub 2017 Nov 6.
Intracellular glycerol accumulation is one of the main fungal adaptations to osmotic and also cold stress. We investigated the management of glycerol metabolism in polyextremotolerant black yeasts Aureobasidium pullulans and Aureobasidium subglaciale. We show that increased salinity (5 % and 10 %; w/v), but not cold (10 °C) trigger intracellular glycerol accumulation. The transcriptional response of the genes involved in glycerol synthesis, degradation and import, to increased salinity, low temperature or a combination of both was analysed with real-time PCR. Each of the two species contains an NAD-dependent glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate phosphatase, a mitochondrial glycerol-3-phosphate dehydrogenase, two copies of a glycerol kinase, and more than ten copies of major facilitator superfamily transporters similar to glycerol proton symporters. Similarly to glycerol accumulation itself, transcriptional response to hypersaline stress was larger compared to low temperature stress and was more consistent in A. pullulans compared to A. subglaciale, reflecting the different stress tolerance and ecological strategy of each species.
细胞内甘油积累是真菌对渗透胁迫和冷胁迫的主要适应性反应之一。我们研究了多极端耐受黑酵母出芽短梗霉和冰川出芽短梗霉中甘油代谢的调控。我们发现，盐度增加（5%和10%；w/v）而非低温（10°C）会引发细胞内甘油积累。通过实时PCR分析了参与甘油合成、降解和转运的基因对盐度增加、低温或两者组合的转录反应。这两个物种均含有一个NAD依赖的甘油-3-磷酸脱氢酶、一个甘油-3-磷酸磷酸酶、一个线粒体甘油-3-磷酸脱氢酶、两个甘油激酶拷贝以及十多个与甘油质子同向转运体相似的主要促进剂超家族转运蛋白拷贝。与甘油积累本身类似，与低温胁迫相比，对高盐胁迫的转录反应更大，并且在出芽短梗霉中比在冰川出芽短梗霉中更一致，这反映了每个物种不同的胁迫耐受性和生态策略。
