Genome Characterization of the Oleaginous Fungus Mortierella alpina

Abstract

Mortierella alpina is an oleaginous fungus which can produce lipids accounting for up to 50% of its dry weight in the form of triacylglycerols. It is used commercially for the production of arachidonic acid. Using a combination of high throughput sequencing and lipid profiling, we have assembled the M. alpina genome, mapped its lipogenesis pathway and determined its major lipid species. The 38.38 Mb M. alpina genome shows a high degree of gene duplications. Approximately 50% of its 12,796 gene models, and 60% of genes in the predicted lipogenesis pathway, belong to multigene families. Notably, M. alpina has 18 lipase genes, of which 11 contain the class 2 lipase domain and may share a similar function. M. alpina's fatty acid synthase is a single polypeptide containing all of the catalytic domains required for fatty acid synthesis from acetyl-CoA and malonyl-CoA, whereas in many fungi this enzyme is comprised of two polypeptides. Major lipids were profiled to confirm the products predicted in the lipogenesis pathway. M. alpina produces a complex mixture of glycerolipids, glycerophospholipids and sphingolipids. In contrast, only two major sterol lipids, desmosterol and 24(28)-methylene-cholesterol, were detected. Phylogenetic analysis based on genes involved in lipid metabolism suggests that oleaginous fungi may have acquired their lipogenic capacity during evolution after the divergence of Ascomycota, Basidiomycota, Chytridiomycota and Mucoromycota. Our study provides the first draft genome and comprehensive lipid profile for M. alpina, and lays the foundation for possible genetic engineering of M. alpina to produce higher levels and diverse contents of dietary lipids.

Molecular mechanism of substrate specificity for delta 6 desaturase from Mortierella alpina and Micromonas pusilla

“…Previous studies reported that M. alpina had low levels of ALA, SDA, and EPA ( 19 ), and expressed no delta 9 elongase ( Fig. 1 ), as previously demonstrated by M. alpina genome determination ( 18 ). Therefore, even if MaFADS6 had equivalent catalytic effi ciency toward LA and ALA, it would preference of FADS6 for LA and ALA is likely to be different in species which produce greatly divergent levels of -3 and -6 PUFAs.…”

“…Some species of this genus are now used for the commercial production of single cell oil that is rich in AA ( 17 ). Among them, Mortierella alpina (ATCC 32222), whose genome has previously been characterized in our lab ( 18 ), has the ability to synthesize a wide range of PUFAs (up to 50% of its cell dry weight), including AA as high as 40% of total fatty acid. By contrast, its -3 PUFA level is low ( 18 ).…”

“…Among them, Mortierella alpina (ATCC 32222), whose genome has previously been characterized in our lab ( 18 ), has the ability to synthesize a wide range of PUFAs (up to 50% of its cell dry weight), including AA as high as 40% of total fatty acid. By contrast, its -3 PUFA level is low ( 18 ). Therefore, M. alpina was used as the other source of FADS6.…”

Whole Genome Sequencing and the Zygomycota

“…Genome data will help us to understand the role of these fungi in natural ecosystems, and to utilize their industrial potential (production of poly-unsaturated fatty acids) more efficiently. Genome and transriptome data are available now for three species: Mortierella verticillata [12], M. elongata [13], and M. alpina [14].…”

Genome sequences published outside of Standards in Genomic Sciences, December 2011

“…Borrelia garinii PBr, sequence accession ABJV02000001-5 (Chromosome), CP001309 (Ip17), CP001301 (Ip25), CP001310 (Ip28-1), CP001307 (Ip28-3), CP001304 (Ip28-4), CP001311 (Ip28-7), CP001302 (Ip36), CP001308 (Ip54), CP001305 (Ip26), CP001303 (Ip32-5), CP001306 (Ip32-10) [24] Borrelia garinii Far 04, sequence accession ABPZ02000001-33 (Chromosome), CP001315 (Ip17), CP001317 (Ip25), CP001316 (Ip28-1), CP001314 (Ip36), CP001318 (Ip54), CP001319 (Ip26), CP001320 (Ip32-10) [24] Non-Bacterial genomes B1 Human Adenovirus HAdV-16 strain E26, sequence accession JN860680 [25] B1 Human Adenovirus HAdV-3/16, sequence accession JN860678 [25] B1 Human Adenovirus HAdV-3+7, sequence accession JN860679 [25] B1 Human Adenovirus HAdV-7d2, sequence accession JN860677 [25] B1 Human Adenovirus HAdV-7h, sequence accession JN860676 [25] Bacillus cereus bacteriophage BCP78, sequence accession JN797797 [26] Circoviridae member (not yet validated), sequence accession JF803741 [27] Coccolithovirus Emiliania huxleyi Virus 203, sequence accession JF974291 [28] Cryptococcus gattii BC, sequence accession SRP006436 [29] Erwinia amylovora plasmid pEI70, sequence accession CP002951 [30] Mortierella alpina, sequence accession ADAG00000000 [31] Parvovirus Aj-BtPV-1, sequence accession JN860679 [32] Parvovirus Eh-BtPV-1, sequence accession JN860679 [32] Penicillium marneffei PM1, sequence accession AGCC00000000 [33] Pseudomonas fluorescens phage OBP, sequence accession JN627160 [34] Salmonella bacteriophage SPN3US, sequence accession JN641803 [35] Tailam virus, sequence accession JN689227 [36] …”