Project description:Oleaginous yeasts are capable of accumulating high levels of intracellular storage lipids from excess carbon during times when other key nutrients are limited. The basidiomycete yeast Rhodosporidium toruloides is an emerging host for microbial cell factory applications thanks to its naturally high lipid and carotenoid production. However, the engineering toolbox in this non-model host is limited and is currently a bottleneck for implementation of metabolic engineering strategies. In this study, we performed differential gene expression analysis with the goal to identify promoters that are strongly induced or repressed by nitrogen-limitation, a condition that is commonly used to induce lipid accumulation in oleaginous yeasts. The genome-wide transcriptional response of R. toruloides BOT-A2 was analysed using RNAseq during exponential growth and nitrogen-starvation, with either glucose or xylose as the sole carbon source. To validate the differential gene expression findings, reporter genes were constructed by placing the candidate promoters in control of a fluorescent protein, integrated in BOT-A2 and evaluated in vivo.
Project description:This RNA-seq study examines transcriptional responses of a cyanobacterium–yeast co-culture system comprising Synechococcus elongatus PCC 7942 and Rhodotorula toruloides NBRC 0880 (Rhodosporidium toruloides IFO0880) under multiple conditions. Experiments included planktonic co-cultures in 50 mL tubes subjected to chemical stressors (oxidative stress, photosynthesis inhibition), temperature stress, nutrient limitation (nitrogen, phosphorus), pH extremes, and heterotrophic conditions, as well as physically separated co-cultures in a 600 mL membrane bioreactor. Axenic controls for Synechococcus elongatus PCC 7942 were included for comparison. Differential gene expression analysis provides insight into interspecies interactions and individual organism responses across co-culture configurations.