Abstract
This study aimed to validate the physiological importance of Arabidopsis thaliana alternative oxidase 1a (AtAOX1a) in alleviating oxidative stress using Saccharomyces cerevisiae as a model organism. The AOX1a transformant (pYES2AtAOX1a) showed cyanide resistant and salicylhydroxamic acid (SHAM)‐sensitive respiration, indicating functional expression of AtAOX1a in S. cerevisiae. After exposure to oxidative stress, pYES2AtAOX1a showed better survival and a decrease in reactive oxygen species (ROS) when compared to S. cerevisiae with empty vector (pYES2). Furthermore, pYES2AtAOX1a sustained growth by regulating GPX2 and/or TSA2, and cellular NAD +/NADH ratio. Thus, the expression of AtAOX1a in S. cerevisiae enhances its respiratory tolerance which, in turn, maintains cellular redox homeostasis and protects from oxidative damage.
Highlights
Alternative oxidase (AOX) is a nonproton pumping ubiquinol oxidase localized in the inner mitochondrial membrane of higher plants, fungi, some protists and was recently identified in 28 animal species [1]
The expression of alternative oxidase 1a (AtAOX1a) protein induced in the presence of 0.1 mM IPTG in E. coli was visualized on SDS/PAGE as a ~ 36 kDa band as it includes
To ascertain the function of AtAOX1a, cyanide-sensitive respiration was monitored using 1 mM KCN, an inhibitor of complex IV in c oxidase (COX) pathway, while cyanide-insensitive respiration was monitored in the presence of 2 mM salicylhydroxamic acid (SHAM) or 100 lM propyl gallate (PG), inhibitors of AOX in the alternative pathway
Summary
Alternative oxidase (AOX) is a nonproton pumping ubiquinol oxidase localized in the inner mitochondrial membrane of higher plants, fungi, some protists and was recently identified in 28 animal species [1]. In contrast to cytochrome c oxidase (COX), it is cyanide resistant and branches from the ‘standard’ mitochondrial respiratory chain at the level of ubiquinone (UQ) It is considered as a sink for excess electrons as it reduces the molecular oxygen to water, bypassing the oxidative phosphorylation at both complex III and IV. AOX overexpression lines showed an enhanced photosynthetic efficiency with lower levels of cellular ROS when compared with wild-type plants during abiotic stress conditions [20,21,22]. A direct or an indirect role of AOX has been demonstrated in maintaining redox homeostasis in higher plants in response to several abiotic stresses [18,19,40,41,42] Such type of significance for AOX is yet to be elucidated in lower organisms
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
