|Goodwin, Stephen - Steve
|MCCORISON, CASSANDRA - Purdue University
|CULLEY, DAVID - Pacific Northwest National Laboratory
|LABUTTI, KURT - Joint Genome Institute
|BAKER, SCOTT - Pacific Northwest National Laboratory
|GRIGORIEV, IGOR - Joint Genome Institute
Submitted to: Fungal Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2016
Publication Date: 6/8/2016
Citation: Goodwin, S.B., McCorison, C.B., Cavaletto, J.R., Culley, D.E., LaButti, K., Baker, S.E., Grigoriev, I.V. 2016. The mitochondrial genome of the ethanol-metabolizing, wine cellar mold Zasmidium cellare is the smallest for a filamentous ascomycete. Fungal Biology. 120(8): 961-974. doi: 10.1016/j.funbio.2016.05.003.
Interpretive Summary: The wine cellar mold Zasmidium cellare produces thick growth that covers the walls of cellars with high humidity, and its ability to metabolize alcohol and other volatile organic compounds is thought to improve air quality, but whether these abilities have affected its mitochondrial genome is not known. To fill this gap, its mitochondrial genome was assembled and annotated. The Z. cellare mitochondrial genome is the smallest reported for a filamentous fungus, yet contains the complete set of essential genes seen typically in other filamentous fungi. The small size of the Z. cellare mitochondrial genome was due to a general paring down rather than a loss of essential genes. This information will be useful to evolutionary biologists and geneticists for understanding mitochondrial genome evolution and to plant pathologists as a comparison for mitochondrial genomes of related fungi that infect plants.
Technical Abstract: The wine cellar mold, Zasmidium cellare, produces thick curtains of mycelia in cellars with high humidity, and its ability to metabolize volatile organic compounds is thought to improve air quality. Whether these abilities have affected its mitochondrial genome is not known. To fill this gap, its mitochondrial genome was assembled and annotated. The circular-mapping mitochondrial genome, at only 23,743 bp, is the smallest yet reported for a filamentous fungus. It contains the complete set of 14 protein-coding genes seen typically in other filamentous fungi, along with genes for ribosomal RNA subunits and tRNA genes capable of decoding all 20 amino acids. The Z. cellare mitochondrial genome had genes encoded on both strands with a single change of direction, and only a low level of microsynteny was observed among protein-coding genes in comparison with Mycosphaerella graminicola (synonym Zymoseptoria tritici), the only other fungus in the order Capnodiales with a sequenced mitochondrial genome. This synteny involved the three gene pairs atp8-atp9, nad2-nad3 and nad4L-nad5. However, even this low level of microsynteny did not extend to other fungi in the Dothideomycetes and Eurotiomycetes. Phylogenetic analysis of mitochondrial genes confirmed the relationship between Z. cellare and M. graminicola in the Capnodiales. Other than its small size, the only unusual feature of the Z. cellare mitochondrial genome was two copies of a 110-bp sequence that were duplicated, inverted and separated by approximately 1 kb that confused the assembly program but appears to have no functional significance. The small size of the Z. cellare mitochondrial genome did not involve a loss of essential genes. Whether this reduction facilitates its unusual biology remains unknown.