title: Pooled segregant sequencing reveals genetic determinants of yeast pseudohyphal growth.
abstract: The pseudohyphal growth response is a dramatic morphological transition and presumed foraging mechanism wherein yeast cells form invasive and surface-spread multicellular filaments. Pseudohyphal growth has been studied extensively as a model of conserved signaling pathways controlling stress responses, cell morphogenesis, and fungal virulence in pathogenic fungi. The genetic contribution to pseudohyphal growth is extensive, with at least 500 genes required for filamentation; as such, pseudohyphal growth is a complex trait, and linkage analysis is a classical means to dissect the genetic basis of a complex phenotype. Here, we implemented linkage analysis by crossing each of two filamentous strains of Saccharomyces cerevisiae (Σ1278b and SK1) with an S288C-derived non-filamentous strain. We then assayed meiotic progeny for filamentation and mapped allelic linkage in pooled segregants by whole-genome sequencing. This analysis identified linkage in a cohort of genes, including the negative regulator SFL1, which we find contains a premature stop codon in the invasive SK1 background. The S288C allele of the polarity gene PEA2, encoding Leu409 rather than Met, is linked with non-invasion. In Σ1278b, the pea2-M409L mutation results in decreased invasive filamentation and elongation, diminished activity of a Kss1p MAPK pathway reporter, decreased unipolar budding, and diminished binding of the polarisome protein Spa2p. Variation between SK1 and S288C in the mitochondrial inner membrane protein Mdm32p at residues 182 and 262 impacts invasive growth and mitochondrial network structure. Collectively, this work identifies new determinants of pseudohyphal growth, while highlighting the coevolution of protein complexes and organelle structures within a given genome in specifying complex phenotypes.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Qingxuan
authors.initials: Q
authors.lastname: Song
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Cole
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Departments of Pathology and Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wilson
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Anuj
authors.initials: A
authors.lastname: Kumar
mesh_terms: D000483:Alleles; D016764:Cell Polarity / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D008040:Genetic Linkage; D025301:Hyphae / Q000235:genetics* / Q000254:growth & development; D008840:Microfilament Proteins / Q000235:genetics*; D051336:Mitochondrial Membranes / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D015398:Signal Transduction
chemical_list: D003598:Cytoskeletal Proteins; C497848:Mdm32 protein, S cerevisiae; D008840:Microfilament Proteins; D024101:Mitochondrial Proteins; C102138:PEA2 protein, S cerevisiae; C065889:SPA2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C541984:KSS1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases