Phylogenomic datasets continue to enhance our understanding of evolutionary relationships in many lineages of organisms.However,genome-scale data have not been widely implemented in reconstructing relationships in lic...Phylogenomic datasets continue to enhance our understanding of evolutionary relationships in many lineages of organisms.However,genome-scale data have not been widely implemented in reconstructing relationships in lichenized fungi.Here we generate a data set comprised of 2556 single-copy protein-coding genes to reconstruct previously unresolved rela-tionships in the most diverse family of lichen-forming fungi,Parmeliaceae.Our sampling included 51 taxa,mainly from the subfamily Parmelioideae,and represented six of the seven previously identified major clades within the family.Our results provided strong support for the monophyly of each of these major clades and most backbone relationships in the topology were recovered with high nodal support based on concatenated dataset and species tree analyses.The alectorioid clade was strongly supported as sister-group to all remaining clades,which were divided into two major sister-groups.In the first major clade the anzioid and usneoid clades formed a strongly supported sister-group relationship with the cetrarioid?hypogymnioid group.The sister-group relationship of Evernia with the cetrarioid clade was also strongly supported,whereas that between the anzioid and usneoid clades needs further investigation.In the second major clade Oropogon and Platismatia were sister to the parmelioid group,while the position of Omphalora was not fully resolved.This study demonstrates the power of genome-scale data sets to resolve long-standing,ambiguous phylogenetic rela-tionships of lichen-forming fungi.Furthermore,the topology inferred in this study will provide a valuable framework for better understanding diversification in the most diverse lineage of lichen-forming fungi,Parmeliaceae.展开更多
Lichens are symbiotic associations resulting from interactions among fungi(primary and secondary mycobionts),algae and/or cyanobacteria(primary and secondary photobionts),and specific elements of the bacterial microbi...Lichens are symbiotic associations resulting from interactions among fungi(primary and secondary mycobionts),algae and/or cyanobacteria(primary and secondary photobionts),and specific elements of the bacterial microbiome associated with the lichen thallus.The question of what is a species,both concerning the lichen as a whole and its main fungal component,the primary mycobiont,has faced many challenges throughout history and has reached new dimensions with the advent of molecular phylogenetics and phylogenomics.In this paper,we briefly revise the definition of lichens and the scientific and vernacular naming conventions,concluding that the scientific,Latinized name usually associated with lichens invariably refers to the primary mycobiont,whereas the vernacular name encompasses the entire lichen.Although the same lichen mycobiont may produce different phenotypes when associating with different photobionts or growing in axenic culture,this discrete variation does not warrant the application of different scientific names,but must follow the principle"one fungus=one name".Instead,broadly agreed informal designations should be used for such discrete morphologies,such as chloromorph and cyanomorph for lichens formed by the same mycobiont but with either green algae or cyanobacteria.The taxonomic recognition of species in lichen-forming fungi is not different from other fungi and conceptual and nomenclatural approaches follow the same principles.We identify a number of current challenges and provide recommendations to address these.Species delimitation in lichen-forming fungi should not be tailored to particular species concepts but instead be derived from empirical evidence,applying one or several of the following principles in what we call the LPR approach:lineage(L)coherence vs.divergence(phylogenetic component),phenotype(P)coherence vs.divergence(morphological component),and/or reproductive(R)compatibility vs.isolation(biological component).Species hypotheses can be established based on either L or P,then using either P or L(plus R)to corroborate them.The reliability of species hypotheses depends not only on the nature and number of characters but also on the context:the closer the relationship and/or similarity between species,the higher the number of characters and/or specimens that should be analyzed to provide reliable delimitations.Alpha taxonomy should follow scientific evidence and an evolutionary framework but should also offer alternative practical solutions,as long as these are scientifically defendable.Taxa that are delimited phylogenetically but not readily identifiable in the field,or are genuinely cryptic,should not be rejected due to the inaccessibility of proper tools.Instead,they can be provisionally treated as undifferentiated complexes for purposes that do not require precise determinations.The application of infraspecific(gamma)taxonomy should be restricted to cases where there is a biological rationale,i.e.,lineages of a species complex that show limited phylogenetic divergence but no evidence of reproductive isolation.Gamma taxonomy should not be used to denote discrete phenotypical variation or ecotypes not warranting the distinction at species level.We revise the species pair concept in lichen-forming fungi,which recognizes sexually and asexually reproducing morphs with the same underlying phenotype as different species.We conclude that in most cases this concept does not hold,but the actual situation is complex and not necessarily correlated with reproductive strategy.In cases where no molecular data are available or where single or multi-marker approaches do not provide resolution,we recommend maintaining species pairs until molecular or phylogenomic data are available.This recommendation is based on the example of the species pair Usnea aurantiacoatra vs.U.antarctica,which can only be resolved with phylogenomic approaches,such as microsatellites or RADseq.Overall,we consider that species delimitation in lichen-forming fungi has advanced dramatically over the past three decades,resulting in a solid framework,but that empirical evidence is still missing for many taxa.Therefore,while phylogenomic approaches focusing on particular examples will be increasingly employed to resolve difficult species complexes,broad screening using single barcoding markers will aid in placing as many taxa as possible into a molecular matrix.We provide a practical pro-tocol how to assess and formally treat taxonomic novelties.While this paper focuses on lichen fungi,many of the aspects discussed herein apply generally to fungal taxonomy.The new combination Arthonia minor(Lücking)Lücking comb.et stat.nov.(Bas.:Arthonia cyanea f.minor Lücking)is proposed.展开更多
Although classification at supra-specific ranks is inherently arbitrary,comparable taxonomic ranks within clades can facilitate more consistent classifications and objective comparisons among taxa.Different circumscri...Although classification at supra-specific ranks is inherently arbitrary,comparable taxonomic ranks within clades can facilitate more consistent classifications and objective comparisons among taxa.Different circumscriptions of the hyper-diverse lichen-forming fungal family Parmeliaceae and widely different generic circumscriptions among authors have been proposed.For this study,we use a recently developed temporal approach that uses timecalibrated chronograms to identify temporal bands for specific ranks in Parmeliaceae and allied groups with the overarching goal of establishing a consistent,stable classification.A data set of 330 species,representing 73 genera in the family and 52 species of related families was used to address the circumscription of Parmeliaceae and its genera following the proposed temporal approach.Based on the results of this study,we propose a revised,temporal-based classification for Parmeliaceae,including all clades that share a common ancestor 102.13–112.88 Ma for families and a time window of 29.45–32.55 Ma for genera.Fortyfive of the currently accepted genera in Parmeliaceae were supported in their current circumscription.Two subfamilies are accepted within Parmeliaceae:Protoparmelioideae Divakar et al.subfam.nov.,including Protoparmelia and the resurrected genus Maronina,and Parmelioideae,including the bulk of genera in the family.The new genus Austromelanelixia Divakar et al.is proposed to accommodate a clade of southern Hemisphere species previously included in Melanelixia.Eumitria and tentatively Dolichousnea are resurrected as genera separate from Usnea.The following genera are reduced to synonymy:Allocetraria,Cetrariella,Usnocetraria,and Vulpicida with Cetraria;Arctocetraria,Cetreliopsis,Flavocetraria,Kaernefeltia,Masonhalea,Tuckermanella,and Tuckermannopsis with Nephromopsis;and the lichenicolous genera Nesolechia and Raesaenenia with the lichen-forming genera Punctelia and Protousnea,respectively.A total of 47 new combinations and three new names at the species level are proposed.展开更多
Abstract The phylogenetic relationship of lecanoroid lichens is studied using two data sets:1)a 2-locus data set including 251 OTUs representing 150 species,and 2)a 6-locus data set with 82 OTUs representing 53 specie...Abstract The phylogenetic relationship of lecanoroid lichens is studied using two data sets:1)a 2-locus data set including 251 OTUs representing 150 species,and 2)a 6-locus data set with 82 OTUs representing 53 species.The genus Lecanora as currently circumscribed is shown to be highly polyphyletic and several genera,including Adelolecia,Arctopeltis,Bryonora,Carbonea,Frutidella,Lecidella,Miriquidica,Palicella,Protoparmeliopsis,Pyrrhospora,and Rhizoplaca are nested within Lecanora sensu lato.A core group of Lecanora is supported as monophyletic and includes species of the L.carpinea,L.rupicola,and L.subcarnea groups,and a core group of the L.subfusca group.Three monophyletic clades that are well supported in our analyses and well characterized by phenotypical characters are accepted here:1)Myriolecis to accommodate the Lecanora dispersa group and Arctopeltis;2)Protoparmeliopsis for the L.muralis group;and 3)Rhizoplaca is emended to include three placodioid taxa previously classified in Lecanora(L.novomexicana.L.opiniconensis,L.phaedrophthalma),whereas R.aspidophora and R.peltata are excluded from Rhizoplaca.The latter is transferred into Protoparmeliopsis.Lecidella is strongly supported as a monophyletic group.Our studies indicate the presence of additional clades of species currently placed in Lecanora sensu lato that warrant taxonomic recognition but additional data will be necessary before the circumscription of these entities is fully understood.37 new combinations are proposed into the genera Myriolecis(30),Protoparmeliopsis(2),and Rhizoplaca(5).展开更多
基金financially supported by the Spanish Ministerio de Ciencia,Innovacion y Universidades(CGL2013-42498-P)the Swedish Research Council(VR 2016-03589)the Negaunee Foundation(‘The greatest radiation in the fungal kingdom’).
文摘Phylogenomic datasets continue to enhance our understanding of evolutionary relationships in many lineages of organisms.However,genome-scale data have not been widely implemented in reconstructing relationships in lichenized fungi.Here we generate a data set comprised of 2556 single-copy protein-coding genes to reconstruct previously unresolved rela-tionships in the most diverse family of lichen-forming fungi,Parmeliaceae.Our sampling included 51 taxa,mainly from the subfamily Parmelioideae,and represented six of the seven previously identified major clades within the family.Our results provided strong support for the monophyly of each of these major clades and most backbone relationships in the topology were recovered with high nodal support based on concatenated dataset and species tree analyses.The alectorioid clade was strongly supported as sister-group to all remaining clades,which were divided into two major sister-groups.In the first major clade the anzioid and usneoid clades formed a strongly supported sister-group relationship with the cetrarioid?hypogymnioid group.The sister-group relationship of Evernia with the cetrarioid clade was also strongly supported,whereas that between the anzioid and usneoid clades needs further investigation.In the second major clade Oropogon and Platismatia were sister to the parmelioid group,while the position of Omphalora was not fully resolved.This study demonstrates the power of genome-scale data sets to resolve long-standing,ambiguous phylogenetic rela-tionships of lichen-forming fungi.Furthermore,the topology inferred in this study will provide a valuable framework for better understanding diversification in the most diverse lineage of lichen-forming fungi,Parmeliaceae.
文摘Lichens are symbiotic associations resulting from interactions among fungi(primary and secondary mycobionts),algae and/or cyanobacteria(primary and secondary photobionts),and specific elements of the bacterial microbiome associated with the lichen thallus.The question of what is a species,both concerning the lichen as a whole and its main fungal component,the primary mycobiont,has faced many challenges throughout history and has reached new dimensions with the advent of molecular phylogenetics and phylogenomics.In this paper,we briefly revise the definition of lichens and the scientific and vernacular naming conventions,concluding that the scientific,Latinized name usually associated with lichens invariably refers to the primary mycobiont,whereas the vernacular name encompasses the entire lichen.Although the same lichen mycobiont may produce different phenotypes when associating with different photobionts or growing in axenic culture,this discrete variation does not warrant the application of different scientific names,but must follow the principle"one fungus=one name".Instead,broadly agreed informal designations should be used for such discrete morphologies,such as chloromorph and cyanomorph for lichens formed by the same mycobiont but with either green algae or cyanobacteria.The taxonomic recognition of species in lichen-forming fungi is not different from other fungi and conceptual and nomenclatural approaches follow the same principles.We identify a number of current challenges and provide recommendations to address these.Species delimitation in lichen-forming fungi should not be tailored to particular species concepts but instead be derived from empirical evidence,applying one or several of the following principles in what we call the LPR approach:lineage(L)coherence vs.divergence(phylogenetic component),phenotype(P)coherence vs.divergence(morphological component),and/or reproductive(R)compatibility vs.isolation(biological component).Species hypotheses can be established based on either L or P,then using either P or L(plus R)to corroborate them.The reliability of species hypotheses depends not only on the nature and number of characters but also on the context:the closer the relationship and/or similarity between species,the higher the number of characters and/or specimens that should be analyzed to provide reliable delimitations.Alpha taxonomy should follow scientific evidence and an evolutionary framework but should also offer alternative practical solutions,as long as these are scientifically defendable.Taxa that are delimited phylogenetically but not readily identifiable in the field,or are genuinely cryptic,should not be rejected due to the inaccessibility of proper tools.Instead,they can be provisionally treated as undifferentiated complexes for purposes that do not require precise determinations.The application of infraspecific(gamma)taxonomy should be restricted to cases where there is a biological rationale,i.e.,lineages of a species complex that show limited phylogenetic divergence but no evidence of reproductive isolation.Gamma taxonomy should not be used to denote discrete phenotypical variation or ecotypes not warranting the distinction at species level.We revise the species pair concept in lichen-forming fungi,which recognizes sexually and asexually reproducing morphs with the same underlying phenotype as different species.We conclude that in most cases this concept does not hold,but the actual situation is complex and not necessarily correlated with reproductive strategy.In cases where no molecular data are available or where single or multi-marker approaches do not provide resolution,we recommend maintaining species pairs until molecular or phylogenomic data are available.This recommendation is based on the example of the species pair Usnea aurantiacoatra vs.U.antarctica,which can only be resolved with phylogenomic approaches,such as microsatellites or RADseq.Overall,we consider that species delimitation in lichen-forming fungi has advanced dramatically over the past three decades,resulting in a solid framework,but that empirical evidence is still missing for many taxa.Therefore,while phylogenomic approaches focusing on particular examples will be increasingly employed to resolve difficult species complexes,broad screening using single barcoding markers will aid in placing as many taxa as possible into a molecular matrix.We provide a practical pro-tocol how to assess and formally treat taxonomic novelties.While this paper focuses on lichen fungi,many of the aspects discussed herein apply generally to fungal taxonomy.The new combination Arthonia minor(Lücking)Lücking comb.et stat.nov.(Bas.:Arthonia cyanea f.minor Lücking)is proposed.
基金The project was financially supported by the Spanish Ministerio de Ciencia e Innovacion(CGL2013-42498-P)the Negaunee Foundation(‘The greatest radiation in the fungal kingdom’)GS was supported by a fellowship from the German Academic Exchange Service(DAAD)and EK by a visiting scholarship from The Field Museum.
文摘Although classification at supra-specific ranks is inherently arbitrary,comparable taxonomic ranks within clades can facilitate more consistent classifications and objective comparisons among taxa.Different circumscriptions of the hyper-diverse lichen-forming fungal family Parmeliaceae and widely different generic circumscriptions among authors have been proposed.For this study,we use a recently developed temporal approach that uses timecalibrated chronograms to identify temporal bands for specific ranks in Parmeliaceae and allied groups with the overarching goal of establishing a consistent,stable classification.A data set of 330 species,representing 73 genera in the family and 52 species of related families was used to address the circumscription of Parmeliaceae and its genera following the proposed temporal approach.Based on the results of this study,we propose a revised,temporal-based classification for Parmeliaceae,including all clades that share a common ancestor 102.13–112.88 Ma for families and a time window of 29.45–32.55 Ma for genera.Fortyfive of the currently accepted genera in Parmeliaceae were supported in their current circumscription.Two subfamilies are accepted within Parmeliaceae:Protoparmelioideae Divakar et al.subfam.nov.,including Protoparmelia and the resurrected genus Maronina,and Parmelioideae,including the bulk of genera in the family.The new genus Austromelanelixia Divakar et al.is proposed to accommodate a clade of southern Hemisphere species previously included in Melanelixia.Eumitria and tentatively Dolichousnea are resurrected as genera separate from Usnea.The following genera are reduced to synonymy:Allocetraria,Cetrariella,Usnocetraria,and Vulpicida with Cetraria;Arctocetraria,Cetreliopsis,Flavocetraria,Kaernefeltia,Masonhalea,Tuckermanella,and Tuckermannopsis with Nephromopsis;and the lichenicolous genera Nesolechia and Raesaenenia with the lichen-forming genera Punctelia and Protousnea,respectively.A total of 47 new combinations and three new names at the species level are proposed.
基金supported by the National Natural Science Foundation of China(31170187,31570017)supported by grant CTM2012-38222-C02-02 from the Spanish Ministry of Economy and Competitiveness.
文摘Abstract The phylogenetic relationship of lecanoroid lichens is studied using two data sets:1)a 2-locus data set including 251 OTUs representing 150 species,and 2)a 6-locus data set with 82 OTUs representing 53 species.The genus Lecanora as currently circumscribed is shown to be highly polyphyletic and several genera,including Adelolecia,Arctopeltis,Bryonora,Carbonea,Frutidella,Lecidella,Miriquidica,Palicella,Protoparmeliopsis,Pyrrhospora,and Rhizoplaca are nested within Lecanora sensu lato.A core group of Lecanora is supported as monophyletic and includes species of the L.carpinea,L.rupicola,and L.subcarnea groups,and a core group of the L.subfusca group.Three monophyletic clades that are well supported in our analyses and well characterized by phenotypical characters are accepted here:1)Myriolecis to accommodate the Lecanora dispersa group and Arctopeltis;2)Protoparmeliopsis for the L.muralis group;and 3)Rhizoplaca is emended to include three placodioid taxa previously classified in Lecanora(L.novomexicana.L.opiniconensis,L.phaedrophthalma),whereas R.aspidophora and R.peltata are excluded from Rhizoplaca.The latter is transferred into Protoparmeliopsis.Lecidella is strongly supported as a monophyletic group.Our studies indicate the presence of additional clades of species currently placed in Lecanora sensu lato that warrant taxonomic recognition but additional data will be necessary before the circumscription of these entities is fully understood.37 new combinations are proposed into the genera Myriolecis(30),Protoparmeliopsis(2),and Rhizoplaca(5).
