RNA-SEQ BASED TRANSCRIPTOME ANALYSIS REVEALS UV-REGULATED GENE EXPRESSION IN A NATIVE ISOLATE OF AUREOBASIDIUM PULLULANS FROM PATAGONIA

MICAELA PARRA; LORENA FRANCO; LUCÍA ÁLVAREZ; DIEGO LIBKIND; CONSUELO OLIVARES-YAÑEZ; NICOLÁS BELLORA

San Carlos de Bariloche, Río Negro

Simposio; 34° International Specialized Symposium on Yeasts (34°ISSY); 2018

Ultraviolet radiation (UVR) is an important harmful factor for biosphere, inducing several stress responses in organisms. The exposure to UVR-B (280-315 nm) can cause direct and indirect cellular damage. For organisms living in extreme conditions, daily exposure to UVR-B (UV from now on) acts as an environmental pressure, selecting strategies to improve their performances against UV-detrimental effects, such as the production of ROS. It is known that several species of fungi are able to produce mycosporines, a biotechnologically important molecule with antioxidant and UV sunscreen activities. We predicted a gene cluster potentially responsible for mycosporine biosynthesis in the genome of Aureobasidium pullulans. This cluster is similar to that reported in the genome of the mycosporinogenic yeast Phaffia rhodozyma. The aim of this work was to characterize global changes in gene expression induced by UV exposure in a native isolate of A. pullulans from Patagonia through aRNA-seq-based transcriptomic approach. We compared RNA-seq results for cultures grown at 20 °C in two conditions: constant darkness and with a 5-min UV pulse. Differential expression analysis of the resulting transcriptomic data showed that 2% of the genes changed their expression as a result of UV exposure, of which about 70% represented upregulated genes. Even though a 5 min UV pulse was not sufficient to trigger a massive de-regulation, our analysis support that UV participates in photo-stimulated processes. As expected, among upregulated genes, we found those belonging to the mycosporine cluster. Surprisingly, we were also able to detect an UV mediated induction of circadian genes. This finding triggers new questions about the effect of UV in endogenous rhythms in fungi.