Genome Assembly and Annotation of a High-Polymalic Acid (PMLA) Producing Strain Aureobasidium melanogenum CGMCC18996 and Analysis of Its Key Proteins Related to PMLA Synthesis

Abstract

In this study, we applied PacBio Sequel II and Illumina NovaSeq 6000 sequencing platforms to sequence the genome of a high-polymalic acid (PMLA)-producing strain, Aureobasidium melanogenum CGMCC18996, and used different assemblers to obtain a high-quality genome assembly, which was then annotated using transcriptomic data. The results indicated a total of 6 202 genes were found in the A. melanogenum genome, mainly involved in carbohydrate transport and metabolism, amino acid transport and metabolism, post-translational modification, RNA processing and modification. Meanwhile, functional annotation revealed that most genes in the genome were related to peroxisome in the strain. Transmission electron microscopy (TEM) indicated the existence of a circular peroxisome-like (glyoxysome) structure in the cells, demonstrating the ability to malic acid through the glyoxylate cycle. Finally, we predicted the protein structures of two enzymes related to PMLA biosynthesis, phosphoenolpyruvate carboxykinase (PCKA) and malate synthase (MASY). It was found that the enzymes could have the ability to synthesize malic acid. This study could provide a reference for metabolism regulation in A. melanogenum for improved PMLA production, and the assembled genome has been uploaded to the database, which could provide the basis for the future development and utilization of A. melanogenum CGMCC18996.

Keywords

• polymalic acid; aureobasidium melanogenum; genome sequencing; genome annotation; protein prediction