Expanding the genetic toolbox of Rhodotorula toruloides by identification and validation of six novel promoters induced or repressed under nitrogen starvation

Abstract Background The non-conventional yeast Rhodotorula toruloides is an emerging host organism in biotechnology by merit of its natural capacity to accumulate high levels carotenoids and intracellular storage lipids from a variety carbon sources. While the number genetic engineering strategies that employ R. increasing, lack tools available for modification this still limiting strain development. For instance, several strong, constitutive promoters have been characterized, but date, only five inducible identified. Although nitrogen-limited cultivation conditions are commonly used induce lipid accumulation yeast, no regulated nitrogen starvation described toruloides. Results In study, we combination genomics transcriptomics methods identify novel promoter sequences either or repressible starvation. RNA sequencing was assess gene expression recently isolated BOT-A2 during exponential growth starvation, when cultivated with glucose xylose as source. genome sequenced using long- short-read annotated support RNAseq data. Differential analysis genes |log 2 fold change|≥ comparing their depletion growth. regions 16 these were evaluated ability drive fluorescent reporter gene. Three clearly upregulated under three downregulated selected further characterized. One promoter, derived RTBOTA2_003877, found function like on–off switch, it full presence Conclusions Six new nitrogen-starvation These substantially contribute foreseen be particularly useful future requiring specific regulation target accordance availability.