Potential Application of the Oryza sativa Monodehydroascorbate Reductase Gene OsMDHAR to Improve the Stress Tolerance and Fermentative Capacity of Saccharomyces cerevisiaeReportar como inadecuado




Potential Application of the Oryza sativa Monodehydroascorbate Reductase Gene OsMDHAR to Improve the Stress Tolerance and Fermentative Capacity of Saccharomyces cerevisiae - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Monodehydroascorbate reductase MDHAR; EC 1.6.5.4 is an important enzyme for ascorbate recycling. To examine whether heterologous expression of MDHAR from Oryza sativa OsMDHAR can prevent the deleterious effects of unfavorable growth conditions, we constructed a transgenic yeast strain harboring a recombinant plasmid carrying OsMDHAR p426GPD::OsMDHAR. OsMDHAR-expressing yeast cells displayed enhanced tolerance to hydrogen peroxide by maintaining redox homoeostasis, proteostasis, and the ascorbate AsA-like pool following the accumulation of antioxidant enzymes and molecules, metabolic enzymes, and molecular chaperones and their cofactors, compared to wild-type WT cells carrying vector alone. The addition of exogenous AsA or its analogue isoascorbic acid increased the viability of WT and ara2Δ cells under oxidative stress. Furthermore, the survival of OsMDHAR-expressing cells was greater than that of WT cells when cells at mid-log growth phase were exposed to high concentrations of ethanol. High OsMDHAR expression also improved the fermentative capacity of the yeast during glucose-based batch fermentation at a standard cultivation temperature 30°C. The alcohol yield of OsMDHAR-expressing transgenic yeast during fermentation was approximately 25% 0.18 g·g-1 higher than that of WT yeast. Accordingly, OsMDHAR-expressing transgenic yeast showed prolonged survival during the environmental stresses produced during fermentation. These results suggest that heterologous OsMDHAR expression increases tolerance to reactive oxygen species-induced oxidative stress by improving cellular redox homeostasis and improves survival during fermentation, which enhances fermentative capacity.



Autor: Il-Sup Kim , Young-Saeng Kim , Yul-Ho Kim, Ae-Kyung Park, Han-Woo Kim, Jun-Hyuk Lee, Ho-Sung Yoon

Fuente: http://plos.srce.hr/



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