Analysis of differentially expressed genes after ex vivo X-rays irradiation of human peripheral white blood cells

The understanding and characterization of the radio-induced response at molecular level is pivotal for developing new approaches on practices that employ Ionizing Radiation (IR). Currently, gene expression signatures are being developed for radiation biodosimetry and as predictive biomarkers for personalizing radiotherapy. In order to detect potential radiation-exposure biomarkers, we performed a bioinformatic meta-analysis of public microarrays of ex vivo X-rays-irradiated human peripheral white blood cells and a validation of the resulting differentially expressed genes (DEGs) by qPCR. Gene expression of five datasets from Gene Expression Omnibus were analyzed with R software and Bioconductor packages. DEGs functional enrichment was performed with Over Representation and Gene Set Enrichment Analysis while iRegulon was used to detect master regulators transcription factors (TF) from DEGs. Human peripheral blood samples from six healthy human donors were X-rays-irradiated at 1-4Gy or left unirradiated. Dicentric Chromosome Assay was performed as biodosimetry control while mRNA from samples was obtained 24 h after exposure for qPCR validations with GAPDH as a reference gene (p-values<0.05 were considered significant). Bioinformatic analysis identified a total of 452 DEGs after X-rays exposure (parameters: lfc=0.7, p-value<0.05). While some of them are well known to be involved in radiation response, others resulted as novel. The DGEs showed enrichment in biological processes such as regulation after IR-exposure, DNA damage checkpoint, signal transduction by p53 and mitotic cell cycle checkpoint. PCNA, TIGAR, DRAM, PLK2 and NUDT15 expressions levels significantly increased at 1-4 Gy vs controls, demonstrated by qPCR. Meanwhile, TCF4 exhibited a significant decrease post-irradiation. This gene was previously detected as a master regulator TF by the bioinformatic analysis.Therefore, the detection and validation of this six DEGs can provide potential candidates as radiation-exposure biomarkers. These findings could also reveal novel insights about molecular networks involved in radio-induce response.Fil: Biolatti, Vanesa. Comisión Nacional de Energía Atómica; ArgentinaFil: Negrin, Lara Maria. Comisión Nacional de Energía Atómica; ArgentinaFil: Bellora, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; ArgentinaFil: Ibañez, Irene Laura. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaLXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica; LXVI Reunión Anual de la Sociedad Argentina de Inmunología y Reunión Anual de la Sociedad Argentina de FisiologíaMar del PlataArgentinaSociedad Argentina de InmunologíaSociedad Argentina de FisiologíaSociedad Argentina de Investigación ClínicaSociedad Argentina de VirologíaSociedad Argentina de Nanomedicina

ILF3 contributes to the establishment of the antiviral type i interferon program

Upon detection of viral infections, cells activate the expression of type I interferons (IFNs) and pro-inflammatory cytokines to control viral dissemination. As part of their antiviral response, cells also trigger the translational shutoff response which prevents translation of viral mRNAs and cellular mRNAs in a non-selective manner. Intriguingly, mRNAs encoding for antiviral factors bypass this translational shutoff, suggesting the presence of additional regulatory mechanisms enabling expression of the self-defence genes. Here, we identified the dsRNA binding protein ILF3 as an essential host factor required for efficient translation of the central antiviral cytokine, IFNB1, and a subset of interferon-stimulated genes. By combining polysome profiling and next-generation sequencing, ILF3 was also found to be necessary to establish the dsRNA-induced transcriptional and translational programs. We propose a central role for the host factor ILF3 in enhancing expression of the antiviral defence mRNAs in cellular conditions where cap-dependent translation is compromised.Fil: Watson, Samir. University of Edinburgh; Reino UnidoFil: Bellora, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; ArgentinaFil: Macias Numa, Sara Magdalena del Valle. University of Edinburgh; Reino Unid

Novel yeast taxa from the cold: description of Cryolevonia giraudoae sp. nov. and Camptobasidium gelus sp. nov.

Twenty-one psychrophilic yeast isolates related to the Camptobasidiaceae family in the Microbotryomycetes class were obtained from ice collected from cold environments worldwide. A new psychrophilic species from the recently described genus Cryole-vonia, Cryolevania giraudoae is proposed to accommodate 18 isolates from Patagonia (Argentina) and Antarctica (holotype CRUB 2086T). In addition, a new psychrophilic species in the genus Camptobasidium is described as Camptobasidium gelus sp. nov. (holotype CBS 8941T), based on three isolates from glacial ice in the Russel glacier (Greenland ice sheet) and Antarctica. The strict psychrophilic profile is the salient feature of both novel species.Fil: de Garcia, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; ArgentinaFil: Trochine, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; ArgentinaFil: Uetake, Jun. National Institute of Polar Research; JapónFil: Bellora, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; ArgentinaFil: Libkind, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; Argentin

Genomic content of a novel yeast species Hanseniaspora gamundiae sp. Nov. From fungal stromata (Cyttaria) associated with a unique fermented beverage in Andean Patagonia, Argentina

A novel yeast species was isolated from the sugar-rich stromata of Cyttaria hariotii collected from two different Nothofagus tree species in the Andean forests of Patagonia, Argentina. Phylogenetic analyses of the concatenated sequence of the rRNA gene sequences and the protein-coding genes for actin and translational elongation factor-1α indicated that the novel species belongs to the genus Hanseniaspora. De novo genome assembly of the strain CRUB 1928 T yielded a 10.2-Mbp genome assembly predicted to encode 4452 protein-coding genes. The genome sequence data were compared to the genomes of other Hanseniaspora species using three different methods, an alignment-free distance measure, K r , and two model-based estimations of DNA-DNA homology values, of which all provided indicative values to delineate species of Hanseniaspora. Given its potential role in a rare indigenous alcoholic beverage in which yeasts ferment sugars extracted from the stromata of Cytarria sp., we searched for the genes that may suggest adaptation of novel Hanseniaspora species to fermenting communities. The SSU1-like gene encoding a sulfite efflux pump, which, among Hanseniaspora, is present only in close relatives to the new species, was detected and analyzed, suggesting that this gene might be one factor that characterizes this novel species. We also discuss several candidate genes that likely underlie the physiological traits used for traditional taxonomic identification. Based on these results, a novel yeast species with the name Hanseniaspora gamundiae sp. nov. is proposed with CRUB 1928 T (ex-types: ZIM 2545 T = NRRL Y-63793 T = PYCC 7262 T ; MycoBank number MB 824091) as the type strain. Furthermore, we propose the transfer of the Kloeckera species, K. hatyaiensis, K. lindneri and K. taiwanica to the genus Hanseniaspora as Hanseniaspora hatyaiensis comb. nov. (MB 828569), Hanseniaspora lindneri comb. nov. (MB 828566) and Hanseniaspora taiwanica comb. nov. (MB 828567).Fil: Čadež, Neža. University of Ljubljana; EsloveniaFil: Bellora, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; ArgentinaFil: Ulloa, José Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; ArgentinaFil: Hittinger, Chris Todd. University of Wisconsin; Estados UnidosFil: Libkind Frati, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentin

Deciphering the transcriptomic regulation of heat stress responses in Nothofagus pumilio

Global warming is predicted to exert negative impacts on plant growth due to the damaging effect of high temperatures on plant physiology. Revealing the genetic architecture underlying the heat stress response is therefore crucial for the development of conservation strategies, and for breeding heat-resistant plant genotypes. Here we investigated the transcriptional changes induced by heat in Nothofagus pumilio, an emblematic tree species of the sub-Antarctic forests of South America. Through the performance of RNA-seq of leaves of plants exposed to 20˚C (control) or 34˚C (heat shock), we generated the first transcriptomic resource for the species. We also studied the changes in protein-coding transcripts expression in response to heat. We found 5,214 contigs differentially expressed between temperatures. The heat treatment resulted in a down-regulation of genes related to photosynthesis and carbon metabolism, whereas secondary metabolism, protein re-folding and response to stress were up-regulated. Moreover, several transcription factor families like WRKY or ERF were promoted by heat, alongside spliceosome machinery and hormone signaling pathways. Through a comparative analysis of gene regulation in response to heat in Arabidopsis thaliana, Populus tomentosa and N. pumilio we provide evidence of the existence of shared molecular features of heat stress responses across angiosperms, and identify genes of potential biotechnological application.Estación Experimental Agropecuaria BarilocheFil: Estravis Barcala, Maximiliano. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Tecnologías Nucleares para la Salud; ArgentinaFil: Heer, Katrin. Philipps-Universitat Marburg; AlemaniaFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Marchelli, Paula. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Ziegenhagen, Birgit. Philipps-Universität Marburg; AlemaniaFil: Arana, María Veronica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Arana, María Veronica. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Bellora Pereyra, Nicolás. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Tecnologías Nucleares para la Salud; Argentin

Nuclear matrix protein Matrin3 regulates alternative splicing and forms overlapping regulatory networks with PTB.

Matrin3 is an RNA- and DNA-binding nuclear matrix protein found to be associated with neural and muscular degenerative diseases. A number of possible functions of Matrin3 have been suggested, but no widespread role in RNA metabolism has yet been clearly demonstrated. We identified Matrin3 by its interaction with the second RRM domain of the splicing regulator PTB. Using a combination of RNAi knockdown, transcriptome profiling and iCLIP, we find that Matrin3 is a regulator of hundreds of alternative splicing events, principally acting as a splicing repressor with only a small proportion of targeted events being co-regulated by PTB. In contrast to other splicing regulators, Matrin3 binds to an extended region within repressed exons and flanking introns with no sharply defined peaks. The identification of this clear molecular function of Matrin3 should help to clarify the molecular pathology of ALS and other diseases caused by mutations of Matrin3.We thank Nejc Haberman (UCL) for assisting in the generation of the splicing maps and preparation of the iCLIP data. This work was supported by Wellcome Trust programme grants to CWJS (077877 and 092900), and by grants to EE and NB BIO2011-23920 and RNAREG (CSD2009-00080) from the Spanish Government and by the Sandra Ibarra Foundation for Cancer (FSI2013). JA was supported by a Boehringer Ingelheim Fonds studentship.This is the final version of the article. It first appeared from EMBO Press/Wiley via http://dx.doi.org/10.15252/embj.20148985

Phytochrome-Mediated Light Perception Affects Fruit Development and Ripening Through Epigenetic Mechanisms

Phytochrome (PHY)-mediated light and temperature perception has been increasingly implicated as important regulator of fruit development, ripening, and nutritional quality. Fruit ripening is also critically regulated by chromatin remodeling via DNA demethylation, though the molecular basis connecting epigenetic modifications in fruits and environmental cues remains largely unknown. Here, to unravel whether the PHY-dependent regulation of fruit development involves epigenetic mechanisms, an integrative analysis of the methylome, transcriptome and sRNAome of tomato fruits from phyA single and phyB1B2 double mutants was performed in immature green (IG) and breaker (BK) stages. The transcriptome analysis showed that PHY-mediated light perception regulates more genes in BK than in the early stages of fruit development (IG) and that PHYB1B2 has a more substantial impact than PHYA in the fruit transcriptome, in both analyzed stages. The global profile of methylated cytosines revealed that both PHYA and PHYB1B2 affect the global methylome, but PHYB1B2 has a greater impact on ripening-associated methylation reprogramming across gene-rich genomic regions in tomato fruits. Remarkably, promoters of master ripening-associated transcription factors (TF) (RIN, NOR, CNR, and AP2a) and key carotenoid biosynthetic genes (PSY1, PDS, ZISO, and ZDS) remained highly methylated in phyB1B2 from the IG to BK stage. The positional distribution and enrichment of TF binding sites were analyzed over the promoter region of the phyB1B2 DEGs, exposing an overrepresentation of binding sites for RIN as well as the PHY-downstream effectors PIFs and HY5/HYH. Moreover, phyA and phyB1B2 mutants showed a positive correlation between the methylation level of sRNA cluster-targeted genome regions in gene bodies and mRNA levels. The experimental evidence indicates that PHYB1B2 signal transduction is mediated by a gene expression network involving chromatin organization factors (DNA methylases/demethylases, histone-modifying enzymes, and remodeling factors) and transcriptional regulators leading to altered mRNA profile of ripening-associated genes. This new level of understanding provides insights into the orchestration of epigenetic mechanisms in response to environmental cues affecting agronomical traits.Fil: Bianchetti, Ricardo. Universidade de Sao Paulo; BrasilFil: Bellora, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de Haro, Luis Alejandro. Weizmann Institute Of Science Israel; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zuccarelli, Rafael. Universidade de Sao Paulo; BrasilFil: Rosado, Daniele. Universidade de Sao Paulo; BrasilFil: Freschi, Luciano. Universidade de Sao Paulo; BrasilFil: Rossi, Magdalena. Universidade de Sao Paulo; BrasilFil: Bermudez Salazar, Luisa Fernanda. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; Argentin

Winter cover crops effects on soil organic carbon and soil physical quality in a typical argiudoll under continuous soybean cropping

The massive adoption of no-tillage (NT), along with the simplification of the cropping sequences has led to physical and chemical degradation of soils. To recover degraded soils, cover crops have been proposed as an alternative to increase soil organic carbon (SOC) and to improve soil physical quality (SPQ). This study aimed (i) to determine the content of SOC and its physical and chemical fractions at different layers and positions, in a soil with a soybean crop under NT with and without winter cover crops, and (ii) to determine SPQ indicators in a soybean crop under NT with and without winter cover crops. Measures and samples were made on a field experiment in a typical Argiudoll of the Argentinean Pampas. Soil organic carbon, coarse and fine particulate organic carbon (POCc and POCf), mineral associated organic carbon (MOC), fulvic acids (FA), humic acids (HA), and humins (H) were determined. Soil physical quality indicators determined were: soil bulk density and total porosity from field samples, and saturated hydraulic conductivity, water-conducting macro and mesoporosity, and total porosity connectivity from field water infiltration data. After eight years, cover crops did not cause any observable change in whole SOC content, but significant differences were observed for some SOC fractions. Humic acids and POCc had 40 and 25 % increases, respectively, in the cover crop treatment. Mineral associated organic carbon and H decreased by 9 and 7 % in cover crop treatment. Soil physical quality did not improve after eight years of cover crops. This can be related to degradation processes after 20 years of soybean monoculture under NT, and to the low ability of Argiudolls to recover from physical degradation.Fil: Salazar, María Paz. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Centro de Investigación para la Sustentabilidad de los Suelos Agrícolas y Forestales; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Física Aplicada I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Soracco, Carlos Germán. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Física Aplicada I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Villarreal, Rafael. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Física Aplicada I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Polich, Nicolás Guillermo. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Centro de Investigación para la Sustentabilidad de los Suelos Agrícolas y Forestales; ArgentinaFil: Bellora, Guido Lautaro. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Centro de Investigación para la Sustentabilidad de los Suelos Agrícolas y Forestales; ArgentinaFil: Turinetto, Matías Javier. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Centro de Investigación para la Sustentabilidad de los Suelos Agrícolas y Forestales; ArgentinaFil: Lozano, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Física Aplicada I; Argentin

Efectos de corto plazo de la inclusión de un cultivo de cobertura bajo siembra directa sobre la calidad física del suelo

Integrating cover crops (CC) in the crop sequence could lead to an enhancement of the notillage (NT) performance improving soil physical quality (SPQ). The objectives of this work were: i- to determine the SPQ on different moments of the crop cycle during the first year after incorporation of cover cropping (barley and vetch) (CC), as compared with bare fallow (BF); and ii- to measure the impact of cover crops on the top soil water content during the first year of its introduction. SPQ indicators were determined from the soil water retention curve (SWRC) and in-situ infiltration data in different dates during the first year after inclusion of CC. The experiment was carried out in a fine, illitic, thermic abruptic Argiudoll. For both treatments, maize was sown as summer crop. CC management showed higher values of plant available water content (PAWC) and Dexter index (S), and lower values of bulk density (BD) as compared with BF. Higher values of field capacity (FC) under CC were observed during the maize growing season. On the other hand, no differences between treatments were observed for Pmac. These results show that the inclusion of CC under NT management improves the soil capacity to retain water and counteract compaction processes under NT. At the end of the crop cycle, higher values of water-conducting macroporosity (εma) and macropore connectivity (Cwma) were observed under CC. Higher values of soil water content during the maize growing period were observed under CC, showing that the inclusion of CC has no negative effects on the top soil water content. Our results show that the inclusion of CC is an opportunity for intensify crop sequences in the Argentinean Pampas Region, oriented to enhance the performance of NT.La inclusión de cultivos de cobertura (CC) puede mejorar el impacto de la siembra directa (NT), derivando en una mayor calidad física del suelo (SPQ). Los objetivos de este trabajo fueron: i- determinar la SPQ en diferentes momentos del ciclo de cultivo durante el primer año después de la introducción de un cultivo de cobertura (CC) de centeno y vicia, en comparación con barbecho desnudo (BF); y ii- medir el impacto de este cultivo de cobertura en el contenido de agua del suelo durante el primer año luego de su introducción, en comparación con BF. Se determinaron indicadores de la SPQ, derivados de la curva de retención hídrica (SWRC) y de ensayos de infiltración in-situ en diferentes momentos durante el primer año luego de la inclusión de un CC. El experimento fue realizado en un Argiudol abrúptico, fino, illítico, térmico. En ambos tratamientos el cultivo de verano fue maíz. El tratamiento CC, en comparación con el tratamiento BF, mostró mayores valores de, agua disponible (PAWC) e índice de Dexter (S), y menores valores de densidad aparente (BD). Se observó una mayor capacidad de campo (FC) bajo CC durante el ciclo de crecimiento del maíz. Por otro lado, no se observaron diferencias entre tratamientos para Pmac, exhibiendo las mismas tendencias temporales. Los resultados muestran que la inclusión de un CC mejora la capacidad de retener agua y contrarrestar procesos de compactación. Al final del ciclo de cultivo, CC mostró mayores valores de macroporosidad conductora de agua (εma) y conectividad de la macroporosidad (Cwma). Se observaron mayores valores de humedad durante el ciclo de cultivo del maíz en el tratamiento CC, mostrando que la inclusión de un CC no tiene un efecto negativo sobre el contenido de agua en el horizonte superficial. Nuestros resultados muestran que la inclusión de CC son una oportunidad de intensificar las secuencias de cultivos en la Región Pampeana Argentina, orientado a mejorar el impacto del sistema de NT.Facultad de Ciencias Agrarias y Forestale

The untapped Australasian diversity of astaxanthin-producing yeasts with biotechnological potential—Phaffia Australis sp. nov. and Phaffia tasmanica sp. nov.

PTDC/BIA-MIC/30785/2017 UIDB/04378/2020 NIH/NIAID R37 MERIT Award AI39115-23 NIH/NIAID R01 AI50113-16Phaffia is an orange-colored basidiomycetous yeast genus of the order Cystofilobasidiales that contains a single species, P. rhodozyma. This species is the only fungus known to produce the economically relevant carotenoid astaxanthin. Although Phaffia was originally found in the Northern hemisphere, its diversity in the southern part of the globe has been shown to be much greater. Here we analyze the genomes of two Australasian lineages that are markedly distinct from P. rhodozyma. The two divergent lineages were investigated within a comprehensive phylogenomic study of representatives of the Cystofilobasidiales that supported the recognition of two novel Phaffia species, for which we propose the names of P. australis sp. nov. and P. tasmanica sp. nov. Comparative genomics and other analyses confirmed that the two new species have the typical Phaffia hallmark—the six genes necessary for the biosynthesis of astaxanthin could be retrieved from the draft genome sequences, and this carotenoid was detected in culture extracts. In addition, the organization of the mating-type (MAT) loci is similar to that of P. rhodozyma, with synteny throughout most regions. Moreover, cases of trans-specific polymorphism involving pheromone receptor genes and pheromone precursor proteins in the three Phaffia species, together with their shared homothallism, provide additional support for their classification in a single genus.publishersversionpublishe