scholarly journals Lager Yeast Comes of Age

2014 ◽  
Vol 13 (10) ◽  
pp. 1256-1265 ◽  
Author(s):  
Jürgen Wendland
Keyword(s):  
Gene Pool ◽  
Population Genomics ◽  
Strain Improvement ◽  
Network Evolution ◽  
Lager Yeast ◽  
Content Type ◽  
Hybrid Nature ◽  
Saccharomyces Pastorianus ◽  
Lager Beer ◽  
Yeast Genomes

ABSTRACTAlcoholic fermentations have accompanied human civilizations throughout our history. Lager yeasts have a several-century-long tradition of providing fresh beer with clean taste. The yeast strains used for lager beer fermentation have long been recognized as hybrids between twoSaccharomycesspecies. We summarize the initial findings on this hybrid nature, the genomics/transcriptomics of lager yeasts, and established targets of strain improvements. Next-generation sequencing has provided fast access to yeast genomes. Its use in population genomics has uncovered many more hybridization events withinSaccharomycesspecies, so that lager yeast hybrids are no longer the exception from the rule. These findings have led us to propose network evolution withinSaccharomycesspecies. This “web of life” recognizes the ability of closely related species to exchange DNA and thus drain from a combined gene pool rather than be limited to a gene pool restricted by speciation. Within the domesticated lager yeasts, two groups, the Saaz and Frohberg groups, can be distinguished based on fermentation characteristics. Recent evidence suggests that these groups share an evolutionary history. We thus propose to refer to the Saaz group asSaccharomyces carlsbergensisand to the Frohberg group asSaccharomyces pastorianusbased on their distinct genomes. New insight into the hybrid nature of lager yeast will provide novel directions for future strain improvement.

scholarly journals A Large Set of Newly Created Interspecific Saccharomyces Hybrids Increases Aromatic Diversity in Lager Beers

2015 ◽  
Vol 81 (23) ◽  
pp. 8202-8214 ◽  
Author(s):  
Stijn Mertens ◽  
Jan Steensels ◽  
Veerle Saels ◽  
Gert De Rouck ◽  
Guido Aerts ◽  
...  
Keyword(s):  
Large Scale ◽  
Alcoholic Beverage ◽  
Pilot Scale ◽  
Temperature Tolerance ◽  
Large Set ◽  
Lager Yeast ◽  
Content Type ◽  
High Attenuation ◽  
Saccharomyces Pastorianus ◽  
Lager Beer

ABSTRACTLager beer is the most consumed alcoholic beverage in the world. Its production process is marked by a fermentation conducted at low (8 to 15°C) temperatures and by the use ofSaccharomyces pastorianus, an interspecific hybrid betweenSaccharomyces cerevisiaeand the cold-tolerantSaccharomyces eubayanus. Recent whole-genome-sequencing efforts revealed that the currently available lager yeasts belong to one of only two archetypes, “Saaz” and “Frohberg.” This limited genetic variation likely reflects that all lager yeasts descend from only two separate interspecific hybridization events, which may also explain the relatively limited aromatic diversity between the available lager beer yeasts compared to, for example, wine and ale beer yeasts. In this study, 31 novel interspecific yeast hybrids were developed, resulting from large-scale robot-assisted selection and breeding between carefully selected strains ofS. cerevisiae(six strains) andS. eubayanus(two strains). Interestingly, many of the resulting hybrids showed a broader temperature tolerance than their parental strains and referenceS. pastorianusyeasts. Moreover, they combined a high fermentation capacity with a desirable aroma profile in laboratory-scale lager beer fermentations, thereby successfully enriching the currently available lager yeast biodiversity. Pilot-scale trials further confirmed the industrial potential of these hybrids and identified one strain, hybrid H29, which combines a fast fermentation, high attenuation, and the production of a complex, desirable fruity aroma.

scholarly journals Creation and Characterization of Industrially Applicable de Novo Lager Yeast Hybrids with a Unique Genomic Architecture

2020 ◽  
Author(s):  
Zachari Turgeon ◽  
Thomas Sierocinski ◽  
Cedric A. Brimacombe ◽  
Yiqiong Jin ◽  
Brittany Goldhawke ◽  
...  
Keyword(s):  
De Novo ◽  
Phenotypic Diversity ◽  
Breeding Strategy ◽  
Lager Yeast ◽  
Genomic Architecture ◽  
Group I ◽  
Saccharomyces Pastorianus ◽  
Lager Beer ◽  
Group Ii ◽  
Beer Production

Lager beer is produced by Saccharomyces pastorianus, which is a natural allopolyploid hybrid between Saccharomyces cerevisiae and Saccharomyces eubayanus. Lager strains are classified into two major groups based largely on genomic composition: Group I and Group II. Group I strains are allotriploid, whereas Group II are allotetraploid. A lack of phenotypic diversity in commercial lager strains has led to substantial interest in the reconstitution of de novo allotetraploid lager strains by hybridization of S. cerevisiae and S. eubayanus strains. Such strategies rely on the hybridization of wild S. eubayanus isolates, which carry unacceptable traits for commercial lager beer such as phenolic off-flavours and incomplete utilization of carbohydrates. Using an alternative breeding strategy, we have created de novo lager hybrids containing the domesticated S. eubayanus subgenome from an industrial S. pastorianus strain by hybridizing diploid meiotic segregants of this strain to a variety of S. cerevisiae ale strains. Five de novo hybrids were isolated which had fermentation characteristics similar to those of prototypical commercial lager strains but with unique phenotypic variation due to the contributions of the S. cerevisiae parents. Genomic analysis of these de novo lager hybrids identified novel allotetraploid genomes carrying three copies of the S. cerevisiae genome and one copy of the S. eubayanus genome. Most importantly, these hybrids do not possess the negative traits which result from breeding wild S. eubayanus. The de novo lager strains produced using industrial S. pastorianus in this study are immediately suitable for industrial lager beer production. IMPORTANCE All lager beer is produced using two related lager yeast types: Group I and Group II, which are highly similar resulting in a lack of strain diversity for lager beer production. To date, approaches for generating new lager yeasts have generated strains possessing undesirable brewing characteristics which render them commercially inviable. We have used an alternative approach that circumvents this issue and created new lager strains that are directly suitable for lager beer production. These novel lager strains also possess a unique genomic architecture, which may lead to a better understanding of industrial yeast hybrids. We propose that strains created using our approach be classified as a third group of lager strains (Group III). We anticipate that these novel lager strains will be of great industrial relevance, and that this technique will be applicable to the creation of additional novel lager strains that will help broaden the diversity in commercial lager beer strains.

scholarly journals Himalayan Saccharomyces eubayanus Genome Sequences Reveal Genetic Markers Explaining Heterotic Maltotriose Consumption by Saccharomyces pastorianus Hybrids

2019 ◽  
Vol 85 (22) ◽  
Author(s):  
Nick Brouwers ◽  
Anja Brickwedde ◽  
Arthur R. Gorter de Vries ◽  
Marcel van den Broek ◽  
Susan M. Weening ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Alcoholic Beverage ◽  
Evolutionary Origin ◽  
Transcription Activator ◽  
High Sequence Identity ◽  
Content Type ◽  
Maltose Metabolism ◽  
Saccharomyces Pastorianus ◽  
Lager Beer ◽  
Saccharomyces Eubayanus

ABSTRACT Saccharomyces pastorianus strains are hybrids of Saccharomyces cerevisiae and Saccharomyces eubayanus that have been domesticated for centuries in lager beer brewing environments. As sequences and structures of S. pastorianus genomes are being resolved, molecular mechanisms and evolutionary origins of several industrially relevant phenotypes remain unknown. This study investigates how maltotriose metabolism, a key feature in brewing, may have arisen in early S. eubayanus × S. cerevisiae hybrids. To address this question, we generated a nearly complete genome assembly of Himalayan S. eubayanus strains of the Holarctic subclade. This group of strains has been proposed to be the S. eubayanus subgenome origin of current S. pastorianus strains. The Himalayan S. eubayanus genomes harbored several copies of an S. eubayanus AGT1 (SeAGT1) α-oligoglucoside transporter gene with high sequence identity to genes encountered in S. pastorianus. Although Himalayan S. eubayanus strains cannot grow on maltose and maltotriose, their maltose-hydrolase and SeMALT1 and SeAGT1 maltose transporter genes complemented the corresponding null mutants of S. cerevisiae. Expression, in Himalayan S. eubayanus of a functional S. cerevisiae maltose metabolism regulator gene (MALx3) enabled growth on oligoglucosides. The hypothesis that the maltotriose-positive phenotype in S. pastorianus is a result of heterosis was experimentally tested by constructing an S. cerevisiae × S. eubayanus laboratory hybrid with a complement of maltose metabolism genes that resembles that of current S. pastorianus strains. The ability of this hybrid to consume maltotriose in brewer’s wort demonstrated regulatory cross talk between subgenomes and thereby validated this hypothesis. These results support experimentally the new postulated hypothesis on the evolutionary origin of an essential phenotype of lager brewing strains and valuable knowledge for industrial exploitation of laboratory-made S. pastorianus-like hybrids. IMPORTANCE S. pastorianus, an S. cerevisiae × S. eubayanus hybrid, is used for production of lager beer, the most produced alcoholic beverage worldwide. It emerged by spontaneous hybridization and colonized early lager brewing processes. Despite accumulation and analysis of genome sequencing data of S. pastorianus parental genomes, the genetic blueprint of industrially relevant phenotypes remains unresolved. Assimilation of maltotriose, an abundant sugar in wort, has been postulated to be inherited from the S. cerevisiae parent. Here, we demonstrate that although Asian S. eubayanus isolates harbor a functional maltotriose transporter SeAGT1 gene, they are unable to grow on α-oligoglucosides, but expression of S. cerevisiae regulator MAL13 (ScMAL13) was sufficient to restore growth on trisaccharides. We hypothesized that the S. pastorianus maltotriose phenotype results from regulatory interaction between S. cerevisiae maltose transcription activator and the promoter of SeAGT1. We experimentally confirmed the heterotic nature of the phenotype, and thus these results provide experimental evidence of the evolutionary origin of an essential phenotype of lager brewing strains.

scholarly journals Pure and Mixed Genetic Lines of Saccharomyces bayanus and Saccharomyces pastorianus and Their Contribution to the Lager Brewing Strain Genome

2006 ◽  
Vol 72 (6) ◽  
pp. 3968-3974 ◽  
Author(s):  
Sandra Rainieri ◽  
Yukiko Kodama ◽  
Yoshinobu Kaneko ◽  
Kozaburo Mikata ◽  
Yoshihiro Nakao ◽  
...  
Keyword(s):  
Strain Improvement ◽  
Single Type ◽  
Polymorphism Analysis ◽  
Saccharomyces Pastorianus ◽  
Saccharomyces Bayanus ◽  
Brewing Strain ◽  
Lager Beer ◽  
Improvement Programs ◽  
Pure Lines ◽  
Hybrid Lines

ABSTRACT The yeast species Saccharomyces bayanus and Saccharomyces pastorianus are of industrial importance since they are involved in the production process of common beverages such as wine and lager beer; however, they contain strains whose variability has been neither fully investigated nor exploited in genetic improvement programs. We evaluated this variability by using PCR-restriction fragment length polymorphism analysis of 48 genes and partial sequences of 16. Within these two species, we identified “pure” strains containing a single type of genome and “hybrid” strains that contained portions of the genomes from the “pure” lines, as well as alleles termed “Lager” that represent a third genome commonly associated with lager brewing strains. The two pure lines represent S. uvarum and S. bayanus, the latter a novel group of strains that may be of use in strain improvement programs. Hybrid lines identified include (i) S. cerevisiae/S. bayanus/Lager, (ii) S. bayanus/S. uvarum/Lager, and (iii) S. cerevisiae/S. bayanus/S. uvarum/Lager. The genome of the lager strains may have resulted from chromosomal loss, replacement, or rearrangement within the hybrid genetic lines. This study identifies brewing strains that could be used as novel genetic sources in strain improvement programs and provides data that can be used to generate a model of how naturally occurring and industrial hybrid strains may have evolved.

Entrepreneurs’ network evolution – the relevance of cognitive social capital

2015 ◽  
Vol 21 (2) ◽  
pp. 197-223 ◽  
Author(s):  
Sara Jonsson
Keyword(s):  
Social Capital ◽  
Private Information ◽  
Three Dimensional ◽  
Network Evolution ◽  
Fashion Industry ◽  
Cognitive Dimension ◽  
Content Type ◽  
Start Up ◽  
The Creation ◽  
Cognitive Social Capital

Purpose – The purpose of this paper is to investigate entrepreneurs’ network evolution in the start-up phase. Design/methodology/approach – Based on the case studies of six fashion start-up firms, this study uses a three-dimensional perspective on social capital (structural, relational, cognitive) to investigate entrepreneurs’ network evolution (i.e. initiation of new relationships) in the start-up phase so as to acquire resources and support for firms’ goals. The study focuses particularly on the understudied cognitive dimension of social capital. The fashion industry provides a relevant research setting because it is characterised by changes in demand, which generate opportunities for entrepreneurship. Findings – The findings show that the display of cognitive attributes is important for the creation of structural social capital (the establishment of new relationships). The findings also indicate that relationships initiated based on the cognitive dimension have a high probability of developing into embedded relationships, thereby becoming high in the relational dimension and providing access to private information containing referrals to other actors. Thus, these relationships also promote the continued development of the structural dimension. Originality/value – The findings imply that the entrepreneurs’ sets of cognitive attributes constitute an important asset in the creation of social capital. They also point to the importance of signalling these values to potential resource holders. Relationships initiated through the display of cognitive attributes can provide resources without requiring immediate economic remuneration.

scholarly journals New Lager Brewery Strains Obtained by Crossing Techniques Using Cachaça (Brazilian Spirit) Yeasts

2017 ◽  
Vol 83 (20) ◽  
Author(s):  
Bruna Inez Carvalho Figueiredo ◽  
Margarete Alice Fontes Saraiva ◽  
Paloma Patrick de Souza Pimenta ◽  
Miriam Conceição de Souza Testasicca ◽  
Geraldo Magela Santos Sampaio ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Low Temperature ◽  
Yeast Strain ◽  
Genetically Modified ◽  
Acetate Esters ◽  
Content Type ◽  
Yeast Strains ◽  
Lager Beer ◽  
New Yeast ◽  
Beer Production

ABSTRACT The development of hybrids has been an effective approach to generate novel yeast strains with optimal technological profile for use in beer production. This study describes the generation of a new yeast strain for lager beer production by direct mating between two Saccharomyces cerevisiae strains isolated from cachaça distilleries: one that was strongly flocculent, and the other with higher production of acetate esters. The first step in this procedure was to analyze the sporulation ability and reproductive cycle of strains belonging to a specific collection of yeasts isolated from cachaça fermentation vats. Most strains showed high rates of sporulation, spore viability, and homothallic behavior. In order to obtain new yeast strains with desirable properties useful for lager beer production, we compare haploid-to-haploid and diploid-to-diploid mating procedures. Moreover, an assessment of parental phenotype traits showed that the segregant diploid C2-1d generated from a diploid-to-diploid mating experiment showed good fermentation performance at low temperature, high flocculation capacity, and desirable production of acetate esters that was significantly better than that of one type lager strain. Therefore, strain C2-1d might be an important candidate for the production of lager beer, with distinct fruit traces and originating using a non-genetically modified organism (GMO) approach. IMPORTANCE Recent work has suggested the utilization of hybridization techniques for the generation of novel non-genetically modified brewing yeast strains with combined properties not commonly found in a unique yeast strain. We have observed remarkable traits, especially low temperature tolerance, maltotriose utilization, flocculation ability, and production of volatile aroma compounds, among a collection of Saccharomyces cerevisiae strains isolated from cachaça distilleries, which allow their utilization in the production of beer. The significance of our research is in the use of breeding/hybridization techniques to generate yeast strains that would be appropriate for producing new lager beers by exploring the capacity of cachaça yeast strains to flocculate and to ferment maltose at low temperature, with the concomitant production of flavoring compounds.

scholarly journals The Frequency of Sex: Population Genomics Reveals Differences in Recombination and Population Structure of the Aflatoxin-Producing Fungus Aspergillus flavus

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Milton T. Drott ◽  
Tatum R. Satterlee ◽  
Jeffrey M. Skerker ◽  
Brandon T. Pfannenstiel ◽  
N. Louise Glass ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Population Genomics ◽  
Population Expansion ◽  
Aflatoxin Production ◽  
The United States ◽  
Aflatoxin Contamination ◽  
Deleterious Mutations ◽  
Content Type ◽  
Sexual And Asexual Reproduction ◽  
Potent Carcinogen

ABSTRACT The apparent rarity of sex in many fungal species has raised questions about how much sex is needed to purge deleterious mutations and how differences in frequency of sex impact fungal evolution. We sought to determine how differences in the extent of recombination between populations of Aspergillus flavus impact the evolution of genes associated with the synthesis of aflatoxin, a notoriously potent carcinogen. We sequenced the genomes of, and quantified aflatoxin production in, 94 isolates of A. flavus sampled from seven states in eastern and central latitudinal transects of the United States. The overall population is subdivided into three genetically differentiated populations (A, B, and C) that differ greatly in their extent of recombination, diversity, and aflatoxin-producing ability. Estimates of the number of recombination events and linkage disequilibrium decay suggest relatively frequent sex only in population A. Population B is sympatric with population A but produces significantly less aflatoxin and is the only population where the inability of nonaflatoxigenic isolates to produce aflatoxin was explained by multiple gene deletions. Population expansion evident in population B suggests a recent introduction or range expansion. Population C is largely nonaflatoxigenic and restricted mainly to northern sampling locations through restricted migration and/or selection. Despite differences in the number and type of mutations in the aflatoxin gene cluster, codon optimization and site frequency differences in synonymous and nonsynonymous mutations suggest that low levels of recombination in some A. flavus populations are sufficient to purge deleterious mutations. IMPORTANCE Differences in the relative frequencies of sexual and asexual reproduction have profound implications for the accumulation of deleterious mutations (Muller’s ratchet), but little is known about how these differences impact the evolution of ecologically important phenotypes. Aspergillus flavus is the main producer of aflatoxin, a notoriously potent carcinogen that often contaminates food. We investigated if differences in the levels of production of aflatoxin by A. flavus could be explained by the accumulation of deleterious mutations due to a lack of recombination. Despite differences in the extent of recombination, variation in aflatoxin production is better explained by the demography and history of specific populations and may suggest important differences in the ecological roles of aflatoxin among populations. Furthermore, the association of aflatoxin production and populations provides a means of predicting the risk of aflatoxin contamination by determining the frequencies of isolates from low- and high-production populations.

scholarly journals Impact of Classical Strain Improvement of Penicillium rubens on Amino Acid Metabolism during β-Lactam Production

2019 ◽  
Vol 86 (3) ◽  
Author(s):  
Min Wu ◽  
Ciprian G. Crismaru ◽  
Oleksandr Salo ◽  
Roel A. L. Bovenberg ◽  
Arnold J. M. Driessen
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Strain Improvement ◽  
Tryptophan Synthase ◽  
Cysteine Biosynthesis ◽  
Penicillin Production ◽  
Content Type ◽  
Classical Strain ◽  
The Impact

ABSTRACT To produce high levels of β-lactams, the filamentous fungus Penicillium rubens (previously named Penicillium chrysogenum) has been subjected to an extensive classical strain improvement (CSI) program during the last few decades. This has led to the accumulation of many mutations that were spread over the genome. Detailed analysis reveals that several mutations targeted genes that encode enzymes involved in amino acid metabolism, in particular biosynthesis of l-cysteine, one of the amino acids used for β-lactam production. To examine the impact of the mutations on enzyme function, the respective genes with and without the mutations were cloned and expressed in Escherichia coli, purified, and enzymatically analyzed. Mutations severely impaired the activities of a threonine and serine deaminase, and this inactivates metabolic pathways that compete for l-cysteine biosynthesis. Tryptophan synthase, which converts l-serine into l-tryptophan, was inactivated by a mutation, whereas a mutation in 5-aminolevulinate synthase, which utilizes glycine, was without an effect. Importantly, CSI caused increased expression levels of a set of genes directly involved in cysteine biosynthesis. These results suggest that CSI has resulted in improved cysteine biosynthesis by the inactivation of the enzymatic conversions that directly compete for resources with the cysteine biosynthetic pathway, consistent with the notion that cysteine is a key component during penicillin production. IMPORTANCE Penicillium rubens is an important industrial producer of β-lactam antibiotics. High levels of penicillin production were enforced through extensive mutagenesis during a classical strain improvement (CSI) program over 70 years. Several mutations targeted amino acid metabolism and resulted in enhanced l-cysteine biosynthesis. This work provides a molecular explanation for the interrelation between secondary metabolite production and amino acid metabolism and how classical strain improvement has resulted in improved production strains.

scholarly journals Primary and Secondary Metabolic Effects of a Key Gene Deletion (ΔYPL062W) in Metabolically Engineered Terpenoid-ProducingSaccharomyces cerevisiae

2019 ◽  
Vol 85 (7) ◽  
Author(s):  
Yan Chen ◽  
Ying Wang ◽  
Ming Liu ◽  
Junze Qu ◽  
Mingdong Yao ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Gene Deletion ◽  
Core Promoter ◽  
Strain Improvement ◽  
Genetic Alterations ◽  
Metabolic Effects ◽  
Industrial Biotechnology ◽  
Cell Factory ◽  
Content Type ◽  
Genetic Function

ABSTRACTSaccharomyces cerevisiaeis an established cell factory for production of terpenoid pharmaceuticals and chemicals. Numerous studies have demonstrated that deletion or overexpression of off-pathway genes in yeast can improve terpenoid production. The deletion ofYPL062WinS. cerevisiae, in particular, has benefitted carotenoid production by channeling carbon toward carotenoid precursors acetyl coenzyme A (acetyl-CoA) and mevalonate. The genetic function ofYPL062Wand the molecular mechanisms for these benefits are unknown. In this study, we systematically examined this gene deletion to uncover the gene function and its molecular mechanism. RNA sequencing (RNA-seq) analysis uncovered thatYPL062Wdeletion upregulated the pyruvate dehydrogenase bypass, the mevalonate pathway, heterologous expression of galactose (GAL) promoter-regulated genes, energy metabolism, and membrane composition synthesis. Bioinformatics analysis and serial promoter deletion assay revealed thatYPL062Wfunctions as a core promoter forALD6and that the expression level ofALD6is negatively correlated to terpenoid productivity. We demonstrate that ΔYPL062Wincreases the production of all major terpenoid classes (C10, C15, C20, C30, and C40). Our study not only elucidated the biological function ofYPL062Wbut also provided a detailed methodology for understanding the mechanistic aspects of strain improvement.IMPORTANCEAlthough computational and reverse metabolic engineering approaches often lead to improved gene deletion mutants for cell factory engineering, the systems level effects of such gene deletions on the production phenotypes have not been extensively studied. Understanding the genetic and molecular function of such gene alterations on production strains will minimize the risk inherent in the development of large-scale fermentation processes, which is a daunting challenge in the field of industrial biotechnology. Therefore, we established a detailed experimental and systems biology approach to uncover the molecular mechanisms ofYPL062Wdeletion inS. cerevisiae, which is shown to improve the production of all terpenoid classes. This study redefines the genetic function ofYPL062W, demonstrates a strong correlation betweenYPL062Wand terpenoid production, and provides a useful modification for the creation of terpenoid production platform strains. Further, this study underscores the benefits of detailed and systematic characterization of the metabolic effects of genetic alterations on engineered biosynthetic factories.

scholarly journals Two Components of a velvet-Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

2010 ◽  
Vol 9 (8) ◽  
pp. 1236-1250 ◽  
Author(s):  
Birgit Hoff ◽  
Jens Kamerewerd ◽  
Claudia Sigl ◽  
Rudolf Mitterbauer ◽  
Ivo Zadra ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
High Performance ◽  
Strain Improvement ◽  
Bimolecular Fluorescence Complementation ◽  
Northern Hybridization ◽  
Penicillin Biosynthesis ◽  
Improvement Program ◽  
Content Type ◽  
Pellet Formation ◽  
Severe Impairment

ABSTRACT Penicillium chrysogenum is the industrial producer of the antibiotic penicillin, whose biosynthetic regulation is barely understood. Here, we provide a functional analysis of two major homologues of the velvet complex in P. chrysogenum, which we have named P. chrysogenum velA (PcvelA) and PclaeA. Data from array analysis using a ΔPcvelA deletion strain indicate a significant role of PcVelA on the expression of biosynthesis and developmental genes, including PclaeA. Northern hybridization and high-performance liquid chromatography quantifications of penicillin titers clearly show that both PcVelA and PcLaeA play a major role in penicillin biosynthesis in a producer strain that underwent several rounds of UV mutagenesis during a strain improvement program. Both regulators are further involved in different developmental processes. While PcvelA deletion leads to light-independent conidial formation, dichotomous branching of hyphae, and pellet formation in shaking cultures, a ΔPclaeA strain shows a severe impairment in conidiophore formation under both light and dark conditions. Bimolecular fluorescence complementation assays provide evidence for a velvet-like complex in P. chrysogenum, with structurally conserved components that have distinct developmental roles, illustrating the functional plasticity of these regulators in genera other than Aspergillus.

Sign in / Sign up

Export Citation Format

Share Document