Ove E. Eriksson

Bio: Ove E. Eriksson is an academic researcher from Umeå University. The author has contributed to research in topics: Juncus roemerianus & Massarina. The author has an hindex of 17, co-authored 22 publications receiving 2811 citations.

The families of bitunicate ascomycetes

Abstract: The morphology and nomenclature of ca. 195 families of bitunicate or alleged bitunicate ascomycetes are discussed. Available representatives of these families were studied especially with respect to the morphology of the asci and ascospores. The morphology of the ascomata, etc. was studied in the SEM in 73 species. The following morphological terms are introduced: hamathecium, pseudoprototunicate, pseudofis–situnicate, semifissitunicate, and umbilicus. The following taxa are described as new: Coccodiniaceae O. Erikss. fam. nov., Microtheliopsidaceae O. Erikss. fam. nov., Amarenomyces O. Erikss. gen. nov., and Euantennaria abietina O. Erikss. sp. nov. The name Lecanidiaceae is proposed to replace Patellariaceae Corda, and Cyanoder–mella to replace Cyanoderma Hohn. The Massariaceae are treated as Trypetheliaceae subfam. Massarioideae (Nits.) O. Erikss. The following new combinations are proposed: Amarenomyces ammophilae (Lasch) O. Erikss., Cyanodermella viridula (Berk. & Curt.) O. Erikss., C. Candida (Setch.) O. Erikss., Dictyotrichiella delicatula (Ves–tergr.) O. Erikss., Laurera sepulta (Mont.) O. Erikss., Splanchnonema superans (Mull. Arg.) O. Erikss. and Thelenella antarctica (M. Lamb) O. Erikss. The origin and evolution of the Ascomycetes are discussed, and the importance of paedomor–phosis in the transspeciation of the group is emphasized. The stratigraphic classification of the Ascomycetes is discussed. In a transitional classification of the Ascomycetes, 109 monophyletic entities (clades) are recognized. La morphologie et la nomenclature ?environ 195 families ?ascomycetes bituniques ou soit–disant bituniques sont etudiees, specialement en respectant la morphologie des asques et des ascospores. La morphologie des ascocarpes, etc. de 73 especes fut etudiee dans le SEM. Les termes morphologiques suivants sont introduits: hamathecium, pseudoprototunique, pseudofissitunique, semifissitunique et umbilicus. Ces nouveaux taxa sont decrits: Coccodiniaceae O. Erikss. fam. nov., Microtheliopsidaceae O. Erikss. fam. nov., Amarenomyces O. Erikss. gen. nov. et Euantennaria abietina O. Erikss. sp. nov. Le nom Lecanidiaceae est proposea la place de Patellariaceae Corda, Cyanodermella a la place de Cyanoderma Hohn. Les Massariaceae sont traitees comme Trypetheliaceae subfam. Massarioideae (Nits.) O. Erikss. Les nouvelles combinations suivantes sont proposees: Amarenomyces ammophilae (Lasch) O. Erikss., Cyanodermella viridula (Berk. & Curt.) O. Erikss., C. Candida (Setch.) O. Erikss., Dictyotrichiella delicatula (Vestergr.) O. Erikss., Laurera sepulta (Mont.) O. Erikss., Splanchnonema superans (Mull. Arg.) O. Erikss. et Thelenella antarctica (M. Lamb) O. Erikss. Ľorigine et ľevolution des ascomycetes sont discutees, et I'importance de la paedomorphose dans la transspeciation du groupe est mise en evidence. La classification stratigraphique des ascomycetes est discutee. Dans une classification de transition des ascomycetes, 109 entites monophyletiques sont reconnues.

Ontogenetic niche shifts and their implications for recruitment in three clonal Vaccinium shrubs: Vaccinium myrtillus, Vaccinium vitis-idaea, and Vaccinium oxycoccos

Abstract: Ontogenetic niche shifts, ie, changes in niche breadth and (or) position during the life of individuals, have received rather limited attention in plant ecology An experiment was designed to assess ontogenetic niche shifts in three clonal Vaccinium shrubs in order to examine their recruitment behavior Seeds were sown, and juveniles transplanted, at sites along a gradient of changing occurrence of the three species Recruitment was seed limited, varied among sites, and was correlated with juvenile survivorship No niche shift occurred during seed to seedling stages for any of the plants For Vaccinium myrtillus L, recruitment was not related to adult occurrence, whereas for Vaccinium oxycoccos L, recruitment was highest at the site where adults dominated However, for both of these species, recruitment also occurred outside the range of adult occurrence Vaccinium vitis-idaea L exhibited a negative relationship between adult occurrence and recruitment and between adult occurrence and juvenile surviv

Neolecta—a fungal dinosaur? Evidence from β-tubulin amino acid sequences

Abstract: Were the first ascomycetes yeast-like (uni- cellular) or filamentous with complex multicellular growth? Molecular studies have indicated that the earliest lineages of ascomycetes were mostly yeast-like and without complex, multicellular fruit bodies. The genus Neolecta stands out as an exception. Neolecta spp. have filamentous growth and discomycete-type of fruit bodies, but constitute one of the basal line- ages both in rRNA and RPB2 gene trees. In this pa- per, we have used 10 previously unpublished and 30 GenBank 13-tubulin genes to test the phylogenetic po- sition of Neolecta spp. We compared the phylogenetic information from the amino acid sequences (485 characters) with the phylogenetic information con- tent of 33 characters from intron gains and losses. Due to gene duplications, two paralogous versions of P3-tubulin genes occurred in four species included in our analysis. Although phylogenetic interpretation of 3-tubulin gene trees was complicated by a history of gene duplications, intron gains and losses, and by un- equal rates of amino acid substitution, Neolecta spe- cies never formed a monophyletic group with any of

Phylogenetic relationships among ascomycetes: evidence from an RNA polymerse II subunit.

Abstract: In an effort to establish a suitable alternative to the widely used 18S rRNA system for molecular systematics of fungi, we examined the nuclear gene RPB2, encoding the second largest subunit of RNA polymerase II. Because RPB2 is a single-copy gene of large size with a modest rate of evolutionary change, it provides good phylogenetic resolution of Ascomycota. While the RPB2 and 18S rDNA phylogenies were highly congruent, the RPB2 phylogeny did result in much higher bootstrap support for all the deeper branches within the orders and for several branches between orders of the Ascomycota. There are several strongly supported phylogenetic conclusions. The Ascomycota is composed of three major lineages: Archiascomycetes, Saccharomycetales, and Euascomycetes. Within the Euascomycetes, plectomycetes, and pyrenomycetes are monophyletic groups, and the Pleosporales and Dothideales are distinct sister groups within the Loculoascomycetes. We confirm the placement of Neolecta within the Archiascomycetes, suggesting that fruiting body formation and forcible discharge of ascospores were characters gained early in the evolution of the Ascomycota. These findings show that a slowly evolving protein-coding gene such as RPB2 is useful for diagnosing phylogenetic relationships among fungi.

Arbuscular mycorrhiza: the mother of plant root endosymbioses.

Abstract: Arbuscular mycorrhiza (AM), a symbiosis between plants and members of an ancient phylum of fungi, the Glomeromycota, improves the supply of water and nutrients, such as phosphate and nitrogen, to the host plant. In return, up to 20% of plant-fixed carbon is transferred to the fungus. Nutrient transport occurs through symbiotic structures inside plant root cells known as arbuscules. AM development is accompanied by an exchange of signalling molecules between the symbionts. A novel class of plant hormones known as strigolactones are exuded by the plant roots. On the one hand, strigolactones stimulate fungal metabolism and branching. On the other hand, they also trigger seed germination of parasitic plants. Fungi release signalling molecules, in the form of 'Myc factors' that trigger symbiotic root responses. Plant genes required for AM development have been characterized. During evolution, the genetic programme for AM has been recruited for other plant root symbioses: functional adaptation of a plant receptor kinase that is essential for AM symbiosis paved the way for nitrogen-fixing bacteria to form intracellular symbioses with plant cells.

The revised classification of eukaryotes

Abstract: This revision of the classification of eukaryotes, which updates that of Adl et al. [J. Eukaryot. Microbiol. 52 (2005) 399], retains an emphasis on the protists and incorporates changes since 2005 that have resolved nodes and branches in phylogenetic trees. Whereas the previous revision was successful in re-introducing name stability to the classification, this revision provides a classification for lineages that were then still unresolved. The supergroups have withstood phylogenetic hypothesis testing with some modifications, but despite some progress, problematic nodes at the base of the eukaryotic tree still remain to be statistically resolved. Looking forward, subsequent transformations to our understanding of the diversity of life will be from the discovery of novel lineages in previously under-sampled areas and from environmental genomic information.