title: Increasing oxidative stress tolerance and subculturing stability of Cordyceps militaris by overexpression of a glutathione peroxidase gene.
abstract: Like other filamentous fungi, the medicinal ascomycete Cordyceps militaris frequently degenerates during continuous maintenance in culture by showing loss of the ability to reproduce sexually or asexually. Degeneration of fungal cultures has been related with cellular accumulation of reactive oxygen species (ROS). In this study, an antioxidant glutathione peroxidase (Gpx) gene from Aspergillus nidulans was engineered into two C. militaris strains, i.e., the Cm01 strain which can fruit normally and the Cm04 strain which has lost the ability to form fruiting bodies on different media through subculturing. The results showed that the mitotically stable mutants had higher Gpx activities and stronger capacity to scavenge cellular ROS than their parental strains. Most significantly, the fruiting ability of Cm04 strain was restored by overexpression of the antioxidant enzyme. However, after being successively transferred for up to ten generations, two of three Cm04 mutants again lost the ability to fruit on insect pupae while Cm01 transformants remained fertile. This study confirms the relationship between fungal culture degeneration and cellular ROS accumulation. Our results indicate that genetic engineering with an antioxidant gene can be an effective way to reverse fungal degeneration during subculturing.
authors: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors: Chenghui
authors: C
authors: Xiong
authors: Yongliang
authors: Y
authors: Xia
authors: Peng
authors: P
authors: Zheng
authors: Chengshu
authors: C
authors: Wang
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics; D002455:Cell Division; D032661:Cordyceps / Q000187:drug effects* / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D015870:Gene Expression; D042822:Genomic Instability; D005979:Glutathione Peroxidase / Q000096:biosynthesis* / Q000235:genetics; D016877:Oxidants / Q000633:toxicity*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000633:toxicity; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012692:Serial Passage
chemical_list: D016877:Oxidants; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D005979:Glutathione Peroxidase