Insight into the Lifestyle of Amoeba Willaertia magna during Bioreactor Growth Using Transcriptomics and Proteomics

Willaertia magna C2c maky is a thermophilic free-living amoeba strain that showed ability to eliminate Legionella pneumophila, a pathogenic bacterium living in the aquatic environment. The amoeba industry has proposed the use of Willaertia magna as a natural biocide to control L. pneumophila proliferation in cooling towers. Here, transcriptomic and proteomic studies were carried out in order to expand knowledge on W. magna produced in a bioreactor. Illumina RNA-seq generated 217 million raw reads. A total of 8,790 transcripts were identified, of which 6,179 and 5,341 were assigned a function through comparisons with National Center of Biotechnology Information (NCBI) reference sequence and the Clusters of Orthologous Groups of proteins (COG) databases, respectively. To corroborate these transcriptomic data, we analyzed the W. magna proteome using LC-MS/MS. A total of 3,561 proteins were identified. The results of transcriptome and proteome analyses were highly congruent. Metabolism study showed that W. magna preferentially consumed carbohydrates and fatty acids to grow. Finally, an in-depth analysis has shown that W. magna produces several enzymes that are probably involved in the metabolism of secondary metabolites. Overall, our multi-omic study of W. magna opens the way to a better understanding of the genetics and biology of this amoeba.