title: Sequence diversity of mating-type genes in Phaeosphaeria avenaria.
abstract: Phaeosphaeria avenaria, one of the causal agents of stagonospora leaf blotch diseases in cereals, is composed of two subspecies, P. avenaria f. sp. triticea (Pat) and P. avenaria f. sp. avenaria (Paa). The Pat subspecies was grouped into Pat1-Pat3, based on restriction fragment length polymorphism (RFLP) and ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequences in previous studies. Mating-type genes and their potential use in phylogeny and molecular classification were studied by DNA hybridization and PCR amplification. The majority of Pat1 isolates reported to be homothallic and producing sexual reproduction structures on cultural media had only the MAT1-1 gene. Minor sequence variations were found in the conserved region of MAT1-1 gene in Pat1 isolates. However, both mating-type genes, MAT1-1 and MAT1-2, were identified in P. avenaria isolates represented by ATCC12277 from oats (Paa) and the Pat2 isolates from foxtail barley ( Hordeum jubatum L.). Cluster analyses based on mating-type gene conserved regions revealed that cereal Phaeosphaeria is not phylogenetically closely related to other ascomycetes, including Mycosphaerella graminicola (anamorph Septoria tritici). The sequence diversity of mating-type genes in Pat and Paa supports our previous phylogenetic relationship and molecular classification based on RFLP fingerprinting and rDNA ITS sequences.
authors.affiliation: Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, ARS, Beltsville, MD 20705, USA. pueng@asrr.arsusda.gov
authors.forename: Peter P
authors.initials: PP
authors.lastname: Ueng
authors.forename: Qun
authors.initials: Q
authors.lastname: Dai
authors.forename: Kai-rong
authors.initials: KR
authors.lastname: Cui
authors.forename: Paweł C
authors.initials: PC
authors.lastname: Czembor
authors.forename: Barry M
authors.initials: BM
authors.lastname: Cunfer
authors.forename: H
authors.initials: H
authors.lastname: Tsang
authors.forename: Edward
authors.initials: E
authors.lastname: Arseniuk
authors.forename: Gary C
authors.initials: GC
authors.lastname: Bergstrom
mesh_terms: D001203:Ascomycota / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D015139:Blotting, Southern; D016000:Cluster Analysis; D017931:DNA Primers; D019143:Evolution, Molecular; D005800:Genes, Fungal / Q000235:genetics*; D049770:Genes, Mating Type, Fungal; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization / Q000235:genetics; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012098:Reproduction / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers