Structure, function, and phylogeny of the mating locus in the Rhizopus oryzae complex.
Abstract
The Rhizopus oryzae species complex is a group of zygomycete fungi that are common,
cosmopolitan saprotrophs. Some strains are used beneficially for production of Asian
fermented foods but they can also act as opportunistic human pathogens. Although R.
oryzae reportedly has a heterothallic (+/-) mating system, most strains have not been
observed to undergo sexual reproduction and the genetic structure of its mating locus
has not been characterized. Here we report on the mating behavior and genetic structure
of the mating locus for 54 isolates of the R. oryzae complex. All 54 strains have
a mating locus similar in overall organization to Phycomyces blakesleeanus and Mucor
circinelloides (Mucoromycotina, Zygomycota). In all of these fungi, the minus (-)
allele features the SexM high mobility group (HMG) gene flanked by an RNA helicase
gene and a TP transporter gene (TPT). Within the R. oryzae complex, the plus (+) mating
allele includes an inserted region that codes for a BTB/POZ domain gene and the SexP
HMG gene. Phylogenetic analyses of multiple genes, including the mating loci (HMG,
TPT, RNA helicase), ITS1-5.8S-ITS2 rDNA, RPB2, and LDH genes, identified two distinct
groups of strains. These correspond to previously described sibling species R. oryzae
sensu stricto and R. delemar. Within each species, discordant gene phylogenies among
multiple loci suggest an outcrossing population structure. The hypothesis of random-mating
is also supported by a 50:50 ratio of plus and minus mating types in both cryptic
species. When crossed with tester strains of the opposite mating type, most isolates
of R. delemar failed to produce zygospores, while isolates of R. oryzae produced sterile
zygospores. In spite of the reluctance of most strains to mate in vitro, the conserved
sex locus structure and evidence for outcrossing suggest that a normal sexual cycle
occurs in both species.
Type
Journal articleSubject
AllelesCrosses, Genetic
DNA Primers
DNA, Fungal
DNA, Ribosomal
Genes, Fungal
Genes, Mating Type, Fungal
L-Lactate Dehydrogenase
Likelihood Functions
Models, Genetic
Phylogeny
Polymerase Chain Reaction
Rhizopus
Sequence Analysis, DNA
Species Specificity
Permalink
https://hdl.handle.net/10161/4588Published Version (Please cite this version)
10.1371/journal.pone.0015273Publication Info
Gryganskyi, AP; Lee, SC; Litvintseva, AP; Smith, ME; Bonito, G; Porter, TM; ... Vilgalys,
R (2010). Structure, function, and phylogeny of the mating locus in the Rhizopus oryzae complex.
PLoS One, 5(12). pp. e15273. 10.1371/journal.pone.0015273. Retrieved from https://hdl.handle.net/10161/4588.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
Collections
More Info
Show full item recordScholars@Duke
Joseph Heitman
Chair, Department of Molecular Genetics and Microbiology
Joseph Heitman was an undergraduate at the University of Chicago (1980-1984), graduating
from the BS-MS program with dual degrees in chemistry and biochemistry with general
and special honors. He then matriculated as an MD-PhD student at Cornell and Rockefeller
Universities and worked with Peter Model and Norton Zinder on how restriction enzymes
recognize specific DNA sequences and how bacteria respond to and repair DNA breaks
and nicks. Dr. Heitman moved as an EMBO long-term fellow to the Bi
Soo Chan Lee
Assistant Research Professor in Molecular Genetics and Microbiology
This author no longer has a Scholars@Duke profile, so the information shown here reflects
their Duke status at the time this item was deposited.
Anastasia P. Litvintseva
Adjunct Assistant Professor in the Department of Molecular Genetics and Microbiology
Rytas J. Vilgalys
Professor of Biology
My scientific work includes traditional and modern research approaches to studying
all areas of mycology including systematics, evolution, medical mycology, plant pathology,
genetics/genomics, and ecology. I am best known for my involvement in the transition
of fungal systematics from a non-quantitative, largely morphologically based science
to the rigorous genome-based discipline that it is today. For the past 20 years,
my lab has been increasingly involved in the study of fungal
Alphabetical list of authors with Scholars@Duke profiles.

Articles written by Duke faculty are made available through the campus open access policy. For more information see: Duke Open Access Policy
Rights for Collection: Scholarly Articles
Works are deposited here by their authors, and represent their research and opinions, not that of Duke University. Some materials and descriptions may include offensive content. More info