title: Morphotype transition and sexual reproduction are genetically associated in a ubiquitous environmental pathogen.
abstract: Sexual reproduction in an environmental pathogen helps maximize its lineage fitness to changing environment and the host. For the fungal pathogen Cryptococcus neoformans, sexual reproduction is proposed to have yielded hyper virulent and drug resistant variants. The life cycle of this pathogen commences with mating, followed by the yeast-hypha transition and hyphal growth, and it concludes with fruiting body differentiation and sporulation. How these sequential differentiation events are orchestrated to ensure developmental continuality is enigmatic. Here we revealed the genetic network of the yeast-to-hypha transition in Cryptococcus by analyzing transcriptomes of populations with a homogeneous morphotype generated by an engineered strain. Among this network, we found that a Pumilio-family protein Pum1 and the matricellular signal Cfl1 represent two major parallel circuits directing the yeast-hypha transition. Interestingly, only Pum1 coordinates the sequential morphogenesis events during a-α bisexual and α unisexual reproduction. Pum1 initiates the yeast-to-hypha transition, partially through a novel filament-specific secretory protein Fas1; Pum1 is also required to sustain hyphal growth after the morphological switch. Furthermore, Pum1 directs subsequent differentiation of aerial hyphae into fruiting bodies in both laboratory and clinical isolates. Pum1 exerts its control on sexual reproduction partly through regulating the temporal expression of Dmc1, the meiosis-specific recombinase. Therefore, Pum1 serves a pivotal role in bridging post-mating morphological differentiation events with sexual reproduction in Cryptococcus. Our findings in Cryptococcus illustrate how an environmental pathogen can ensure the completion of its life cycle to safeguard its long-term lineage success.
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Linqi
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Tian
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Rachana
authors.initials: R
authors.lastname: Gyawali
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Srijana
authors.initials: S
authors.lastname: Upadhyay
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Dylan
authors.initials: D
authors.lastname: Foyle
authors.affiliation: Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, United States of America.
authors.forename: James J
authors.initials: JJ
authors.lastname: Cai
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Lin
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics; D051338:Cofilin 1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D003453:Cryptococcosis / Q000473:pathology; D003455:Cryptococcus neoformans / Q000235:genetics / Q000254:growth & development*; D064429:Fatty Acid Synthases / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics; D055786:Gene Knockout Techniques; D049770:Genes, Mating Type, Fungal; D025301:Hyphae / Q000166:cytology / Q000254:growth & development*; D008018:Life Cycle Stages; D008540:Meiosis / Q000235:genetics; D051379:Mice; D008805:Mice, Inbred A; D009024:Morphogenesis / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012100:Reproduction, Asexual / Q000235:genetics; D015003:Yeasts / Q000166:cytology / Q000254:growth & development; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D018797:Cell Cycle Proteins; D051338:Cofilin 1; D005656:Fungal Proteins; D016601:RNA-Binding Proteins; D064429:Fatty Acid Synthases