Whole Genome Sequencing, De Novo Assembly and Phenotypic Profiling
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INVESTIGATION Whole Genome Sequencing, de Novo Assembly and Phenotypic Profiling for the New Budding Yeast Species Saccharomyces jurei Samina Naseeb,1,2 Haya Alsammar,1 Tim Burgis, Ian Donaldson, Norman Knyazev, Christopher Knight, and Daniela Delneri2 Manchester Institute of Biotechnology, The University of Manchester, UK, M1 7DN ORCID IDs: 0000-0003-3599-5813 (S.N.); 0000-0001-9815-4267 (C.K.); 0000-0001-8070-411X (D.D.) ABSTRACT Saccharomyces sensu stricto complex consist of yeast species, which are not only important in KEYWORDS the fermentation industry but are also model systems for genomic and ecological analysis. Here, we present evolution the complete genome assemblies of Saccharomyces jurei, a newly discovered Saccharomyces sensu stricto fitness species from high altitude oaks. Phylogenetic and phenotypic analysis revealed that S. jurei is more closely PacBio related to S. mikatae, than S. cerevisiae, and S. paradoxus. The karyotype of S. jurei presents two reciprocal translocation chromosomal translocations between chromosome VI/VII and I/XIII when compared to the S. cerevisiae Saccharomyces genome. Interestingly, while the rearrangement I/XIII is unique to S. jurei, the other is in common with S. mikatae strain IFO1815, suggesting shared evolutionary history of this species after the split between S. cerevisiae and S. mikatae. The number of Ty elements differed in the new species, with a higher number of Ty elements present in S. jurei than in S. cerevisiae. Phenotypically, the S. jurei strain NCYC 3962 has relatively higher fitness than the other strain NCYC 3947T under most of the environmental stress conditions tested and showed remarkably increased fitness in higher concentration of acetic acid compared to the other sensu stricto species. Both strains were found to be better adapted to lower temperatures compared to S. cerevisiae. Saccharomyces sensu stricto yeasts, currently comprise eight species: surrounding soil at an altitude of 1000 m above sea level in Saint Auban, S. cerevisiae, S. paradoxus, S. uvarum, S. mikatae, S. kudriavzevii, France (Naseeb et al. 2017b). It is known that species within the sensu S. arboricola, S. eubayanus, S. jurei (Martini and Martini 1987; Wang stricto group are reproductively isolated and possess post- zygotic bar- and Bai 2008; Naumov et al. 2000; Naumov et al. 1995a; Naumov et al. riers (Naumov 1987). Moreover, yeasts within this group exhibit almost 1995b; Libkind et al. 2011; Naseeb et al. 2017b) and two natural hy- identical karyotypes with 16 chromosomes (Cardinali and Martini brids: S. pastorianus (Masneuf et al. 1998; Querol and Bond 2009) and 1994; Carle and Olson 1985; Naumov et al. 1996). S. bayanus (Nguyen et al. 2011). Saccharomyces jurei is the latest ad- In the modern era of yeast genetics, the advances in sequencing dition to the sensu stricto clade and was isolated from oak tree bark and technology have lead to the whole genome sequencing of many Saccharomyces sensu stricto species (S. cerevisiae, S. bayanus var. Copyright © 2018 Naseeb et al. uvarum, S. kudriavzevii, S. mikatae, S. paradoxus, S. eubayanus doi: https://doi.org/10.1534/g3.118.200476 and S. arboricola)(Libkindet al. 2011; Liti et al. 2013; Cliften Manuscript received June 4, 2018; accepted for publication July 11, 2018; et al. 2003; Kellis et al. 2003; Scannell et al. 2011; Casaregola et al. published Early Online August 14, 2018. 2000). To date, more than 1000 S. cerevisiae strains belonging to This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/ different geographical and environmental origins have been se- licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction quenced and assembled (Engel and Cherry 2013; Peter et al. in any medium, provided the original work is properly cited. 2018). The availability of sequencing data from multiple strains of Supplemental material available at Figshare: https://figshare.com/s/ Saccharomycotina yeast species has enhanced our understanding of 60bbbc1e98886077182a. 1These authors contributed equally in this work biological mechanisms and comparative genomics. Researchers are 2Corresponding authors: Samina Naseeb: [email protected]; now combining comparative genomics with population ecology to Daniela Delneri: [email protected] better understand the genetic variations, taxonomy, evolution and Volume 8 | September 2018 | 2967 n Table 1 Strains used in this study Species Strain number References S. jurei NCYC 3947T (Naseeb et al. 2017b) NCYC 3962 S. cerevisiae NCYC 505T (Vaughan Martini and Kurtzman 1985) S. paradoxus CBS 432T (Naumov 1987) S. mikatae NCYC 2888T (IFO 1815T) (Yamada et al. 1993) S. kudriavzevii NCYC 2889T (IFO 1802T) (Yamada et al. 1993) S. arboricola CBS 10644T (Wang and Bai 2008) S. eubayanus PYCC 6148T (CBS 12357T) (Libkind et al. 2011) S. uvarum NCYC 2669 (CBS 7001) (Pulvirenti et al. 2000) S. pastorianus NCYC 329T (CBS 1538T) (Martini and Martini 1987) speciation of yeast strains in nature. Genome variation provides the EDTA and1M DTT) containing 1 mg/ml lyticase. The cells were in- raw material for evolution, and may arise by various mechanisms cubated at 37° for 1 hr. Following incubation, the cells were mixed with including gene duplication, horizontal gene transfer, hybridization stop solution (3M NaCl, 100mM Tris pH 7.5 and 20mM EDTA) and and micro and macro rearrangements (Fischer et al. 2001; Seoighe 60 ml of 10% SDS. The cell suspension was vortexed and mixed with et al. 2000; Lynch 2002; Hall et al. 2005; Naseeb et al. 2017a; Naseeb 500 ml phenol-chloroform. The samples were centrifuged at 13000 rpm et al. 2016; Naseeb and Delneri 2012). Synteny conservation studies for 2 min to separate the aqueous phase from the organic phase. The have shown highly variable rates of genetic rearrangements between upper aqueous phase was transferred to a clean 1.5 ml tube and phenol- individual lineages both in vertebrates and in yeasts (Bourque et al. chloroform step was repeated twice until a white interface was no 2005; Fischer et al. 2006; Vakirlis et al. 2016). This genome variation longer present. The aqueous phase was washed with 1 ml absolute is a means of evolutionary adaptation to environmental changes. An ethanol by centrifugation at 13000 rpm for 10 min. The pellet was air understanding of the genetic machinery linked to phenotypic var- dried and resuspended in 30 ml of sterile milliQ water. iation provides knowledge of the distribution of Saccharomyces spe- Genomic DNA for PacBio sequencing was extracted using Qiagen cies in different environments, and their ability to withstand specific Genomic-tip 20/G kit (cat. No. 10223) following manufacturer’srec- conditions (Goddard and Greig 2015; Jouhten et al. 2016; Brice et al. ommended instructions. The yield of all DNA samples was assessed by 2018; Peter et al. 2018). the nanodrop spectrophotometer (ND-1000) and by Qubit 2.0 fluo- Recently, we isolated two strains (NCYC 3947T and NCYC 3962) of rometer (catalog no. Q32866). Purity and integrity of DNA was Saccharomyces jurei from Quercus robur bark and surrounding soil checked by electrophoresis on 0.8% (w/v) agarose gel and by calculating (Naseeb et al. 2017b). The initial sequencing of ITS1, D1/D2 and seven the A260/A280 ratios. other nuclear genes showed that both strains of S. jurei were closely related to S. mikatae and S. paradoxus and grouped in Saccharomyces Library preparation for Illumina and PacBio sequencing sensu stricto complex. We also showed that S. jurei can readily hybridize Paired end whole-genomesequencingwasperformedusingthe Illumina with other sensu stricto species but the resulting hybrids were sterile HiSeq platform. FastQC (Babraham Bioinformatics) was used to apply (Naseeb et al. 2017b). Here, we represent high quality de novo sequence quality control to sequence reads, alignment of the reads was performed and assembly of both strains (NCYC 3947T and NCYC 3962) of S. jurei. using BOWTIE2 (Langmead and Salzberg 2012) and post-processed The phylogenetic analysis placed S. jurei in the sensu stricto clade, in a using SAMTOOLS (Li et al. 2009). small monophyletic group with S. mikatae. By combining Illumina For Pacbio sequencing, genomic DNA (10 mg) of NCYC 3947T and HiSeq and PacBio data, we were able to assemble full chromosomes NCYC 3962 strains was first DNA damage repaired, sheared with and carry out synteny analysis. Moreover, we show that S. jurei NCYC Covaris G-tube, end repaired and exonuclease treated. SMRTbell li- 3962 had higher fitness compared to NCYC 3947T under different brary (10-20kb size) was prepared by ligation of hairpin adaptors at environmental conditions. Fitness of S. jurei strains at different tem- both ends according to PacBio recommended procedure (Pacific Bio- peratures showed that it was able to grow at wider range of tempera- science, No: 100-259-100). The resulting library was then size selected tures (12°-37°). using Blue Pippin with 7-10kb cut-off. Sequencing run was performed on PacBio RS II using P6/C4 chemistry for 4 hr. The genome was MATERIAL AND METHODS assembled using SMRT analysis and HGAP3 pipeline was made using default settings. Yeast strains Strains used in this study are presented in Table 1. All strains were Genome assembly, annotation, orthology and grown and maintained on YPDA (1% w/v yeast extract, 2% w/v Bacto- chromosomal structural plots peptone, 2% v/v glucose and 2% w/v agar). Species names and strains The PacBio sequences were assembled using hierarchical genome- number are stated in Table 1. assembly process (HGAP) (Chin et al. 2013). Protein coding gene models were predicted using Augustus (Stanke and Morgenstern DNA Extraction 2005) and the Yeast Genome Annotation Pipeline (Byrne and Wolfe For Illumina Hiseq, the total DNA was extracted from an overnight 2005). In addition, protein sequences from other Saccharomyces species grown culture of yeast strains by using the standard phenol/chloroform were aligned to the genome assembly using tblastn (Gertz et al.