Functional Study Of SPT20 Gene In The Mechanism Of Anti-oxidative Damage Of Candida Albicans

Background:Candida albicans is the most prominent fungal pathogen infecting humans.Its morbidity is increasing and the current antifungal treatment is not satisfactory.Therefore,it is necessary to further study the pathogenic mechanism of Candida albicans and find a novel potential drug target.Our research team reported for the first time that the SPT20 gene is an important virulence gene of Candida albicans,which can regulate the viability and virulence of Candida albicans through various pathways.There is little research on SPT20 so far,and the molecular mechanism of its virulence is still unclear.However,it has been reported that the ability of antioxidant damage is an important manifestation of the virulence of Candida albicans,so it is necessary to evaluate the role of SPT20 in the oxidation response of Candida albicans.Aim:SPT20 was evaluated for the role it plays in Candida albicans antioxidant responses as part of this defense mechanism,revealing the underlying molecular mechanism by which it works.Method:We observed the growth of the wild-type,an SPT20 null strain,and a SPT20-complemented strain in YPD agar plates containing H2O2 and measured the intracellular ROS levels with or without H2O2 stimulation by using DCFH-DA.GSH and GSSG Assay Kit was employed to measure the[GSH/GSSG]ratio.The responses to ROS were interrogated through evaluating the expression levels of redox-related genes,and using western blots elucidate phosphorylation of Hogl in the presence of H2O2.Result:Continuous gradient dilution experiments suggest that the loss of SPT20 leads to increased sensitivity of Candida albicans to the exogenous oxidant H202.Compared with the wild-type strain,the ROS level in the SPT20-deficient strain was significantly increased,while the CAT activity,which plays a key role in scavenging ROS,was significantly reduced.At the same time,the[GSH]/[GSSG]ratio of Candida albicans was significantly increased,and the SPT20 deletion strain faced higher oxidative stress.RT-PCR results showed that the deletion of the SPT20 gene resulted in changes in the expression levels of oxidative response-related genes(including CAT1,SOD2,and GLR1),and was consistent with the above results.Western blot analysis further showed that the deletion of SPT20 significantly enhanced the phosphorylation level of Hogl,indicating that it has an important influence on the key pathway of Candida albicans regulation of oxidation response(Hog1-MAPK pathway).Conclusion:In summary,our findings demonstrated that SPT20 plays a role in protecting Candida albicans from external oxidative responses and provided a potential antifungal targets.