Endophytic Colletotrichum Species from Aquatic Plants in Southwest China

Colletotrichum species are plant pathogens, saprobes, and endophytes in many economically important hosts. Many studies have investigated the diversity and pathogenicity of Colletotrichum species in common ornamentals, fruits, and vegetables. However, Colletotrichum species occurring in aquatic plants are not well known. During the investigation of the diversity of endophytic fungi in aquatic plants in southwest China, 66 Colletotrichum isolates were obtained from aquatic plants there, and 26 of them were selected for sequencing and analyses of actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the internal transcribed spacer (ITS) region, and β-tubulin (TUB2) genomic regions. Based on morphological characterization and multi-locus phylogenetic analyses, 13 Colletotrichum species were recognized, namely, C. baiyuense sp. nov., C. casaense sp. nov., C. demersi sp. nov., C. dianense sp. nov., C. fructicola, C. garzense sp. nov., C. jiangxiense, C. karstii, C. philoxeroidis sp. nov., C. spicati sp. nov., C. tengchongense sp. nov., C. vulgaris sp. nov., C. wuxuhaiense sp. nov. Two species complexes, the C. boninense species complex and C. gloeosporioides species complex, were found to be associated with aquatic plants. Pathogenicity tests revealed a broad diversity in pathogenicity and aggressiveness among the eight new Colletotrichum species.

Modular evolution of secretion systems and virulence plasmids in a bacterial species complex

Background Many named species as defined in current bacterial taxonomy correspond to species complexes. Uncertainties regarding the organization of their genetic diversity challenge research efforts. We utilized the Agrobacterium tumefaciens species complex (a.k.a. Agrobacterium biovar 1), a taxon known for its phytopathogenicity and applications in transformation, as a study system and devised strategies for investigating genome diversity and evolution of species complexes. Results We utilized 35 genome assemblies, including 14 newly generated ones, to achieve a phylogenetically balanced sampling of A. tumefaciens. Our genomic analysis suggested that the 10 genomospecies described previously are distinct biological species and supported a quantitative guideline for species delineation. Furthermore, our inference of gene content and core-genome phylogeny allowed for investigations of genes critical in fitness and ecology. For the type VI secretion system (T6SS) involved in interbacterial competition and thought to be conserved, we detected multiple losses and one horizontal gene transfer. For the tumor-inducing plasmids (pTi) and pTi-encoded type IV secretion system (T4SS) that are essential for agrobacterial phytopathogenicity, we uncovered novel diversity and hypothesized their involvement in shaping this species complex. Intriguingly, for both T6SS and T4SS, genes encoding structural components are highly conserved, whereas extensive diversity exists for genes encoding effectors and other proteins. Conclusions We demonstrate that the combination of a phylogeny-guided sampling scheme and an emphasis on high-quality assemblies provides a cost-effective approach for robust analysis in evolutionary genomics. We show that the T6SS VgrG proteins involved in specific effector binding and delivery can be classified into distinct types based on domain organization. The co-occurrence patterns of VgrG-associated domains and the neighboring genes that encode different chaperones/effectors can be used to infer possible interacting partners. Similarly, the associations between plant host preference and the pTi type among these strains can be used to infer phenotype-genotype correspondence. Our strategies for multi-level investigations at scales that range from whole genomes to intragenic domains and phylogenetic depths from between- to within-species are applicable to other bacteria. Furthermore, modularity observed in the molecular evolution of genes and domains is useful for inferring functional constraints and informing experimental works.

DNA Barcoding of Scavenging Amphipod Communities at Active and Inactive Hydrothermal Vents in the Indian Ocean

Hydrothermal vent areas have drawn increasing interest since they were discovered in 1977. Because of chemoautotrophic bacteria, they possess high abundances of vent endemic species as well as many non-vent species around the fields. During the survey conducted by the Bundesanstalt für Geowissenschaften und Rohstoffe (Federal Institute for Geosciences and Natural Resources, BGR) to identify inactive polymetallic sulfide deposits along Central and Southeast Indian Ridges, the INDEX project studied the scavenging amphipod community at three newly discovered hydrothermal fields. A sample consisting of 463 representatives of Amphipoda (Malacostraca: Crustacea) was collected by means of baited traps in active and inactive vents of three different sites and subsequently studied by both morphological and genetic methods. Molecular methods included the analysis of two mitochondrial (cytochrome c oxidase subunit I [COI] and 16S rRNA) and one nuclear (18S rRNA) genes. By six delimitation methods, 22 molecular operational taxonomic units (MOTUs) belonging to 12 genera and 10 families were defined. The existence of potential species complexes was noted for the representatives of the genus Paralicella. The inactive site, where 19 species were found, showed higher species richness than did the active one, where only 10 taxa were recorded. Seven genera, Ambasiopsis, Cleonardo, Eurythenes, Parandania, Pseudonesimus, Tectovalopsis, and Valettiopsis, were observed only at inactive sites, whereas Haptocallisoma, was collected exclusively at active ones. The species Abyssorchomene distinctus (Birstein and Vinogradov, 1960), Hirondellea brevicaudata Chevreux, 1910, and Hirondellea guyoti Barnard and Ingram, 1990, have been previously reported from vent sites in the Atlantic or Pacific oceans. The present study provides the first report of Eurythenes magellanicus (H. Milne Edwards, 1848) and five other already described species in the Indian Ocean. The addition of 356 sequences strongly increases the number of amphipod barcodes in reference databases and provides for the first time COI barcodes for Cleonardo neuvillei Chevreux, 1908, Haptocallisoma abyssi (Oldevig, 1959), Hirondellea guyoti, Tectovalopsis fusilus Barnard and Ingram, 1990, and the genera Haptocallisoma, Pseudonesimus, and Valettiopsis.

Updating species diversity of Colletotrichum, with a phylogenomic overview

The genus Colletotrichum includes important plant pathogens, endophytes, saprobes and human pathogens. Even though the polyphasic approach has facilitated Colletotrichum species identification, knowledge of the overall species diversity and host distribution is largely incomplete. To address this, we examined 952 Colletotrichum strains isolated from plants representing 322 species from 248 genera, or air and soil samples, from 87 locations in China, as well as 56 strains from Saudi Arabia, Thailand, Turkey, and the UK. Based on morphological characteristics and multi-locus phylogenetic analyses, the strains were assigned to 107 species, including 30 new species described in this paper and 18 new records for China. The currently most comprehensive backbone tree of Colletotrichum, comprising 16 species complexes (including a newly introduced C. bambusicola species complex) and 15 singleton species, is provided. Based on these analyses, 280 species with available molecular data are accepted in this genus, of which 139 have been reported in China, accounting for 49.6 % of the species. Colletotrichum siamense, C. karsti, C. fructicola, C. truncatum, C. fioriniae, and C. gloeosporioides were the most commonly detected species in China, as well as the species with the broadest host range. By contrast, 76 species were currently found to be associated with a single plant species or genus in China. To date, 33 Colletotrichum species have been exclusively reported as endophytes. Furthermore, we generated and assembled whole-genome sequences of the 30 new and a further 18 known species. The most comprehensive genome tree comprising 94 Colletotrichum species based on 1 893 single-copy orthologous genes was hence generated, with all nodes, except four, supported by 100 % bootstrap values. Collectively, this study represents the most comprehensive investigation of Colletotrichum diversity and host occurrence to date, and greatly enhances our understanding of the diversity and phylogenetic relationships in this genus.

Recent Advances in Cryptococcus and Cryptococcosis

The members of the Cryptococcus neoformans and Cryptococcus gattii species complexes are the main etiological agents of cryptococcosis, a life-threatening fungal infection affecting mostly immunocompromised people, but also immunocompetent hosts or those with unrecognized risk factors [...]

Characterization of Wild Rice - Oryza Species Complexes in Sri Lanka

Rice is the staple food crop in Sri Lanka, which occupies 34% (0.77/million ha) of the total cultivated area. Sri Lanka currently produces 2.7 million tonnes of rough rice annually and satisfies around 95% of the domestic requirement. In Sri Lanka, genus Oryza consists of two species complexes, O. sativa (AA) and O. officinalis (CC). These two complexes are both pan tropical and have very similar overall distribution. Five wild rice species are reported in Sri Lanka, (O. nivara [AA], O. rufipogan (AA) O. eichengeri [CC], O. rhizomatis (CC) and O. granulate (GG). O. rhizomatis has been reported only in Sri Lanka and considered endemic to Sri Lanka. Recent studies demonstrated, the reliance on single source of information could mislead results in the phylogenetic inferences due to analytical inconsistency and biological processes. Therefore, exact number of wild rice species in Sri Lanka becomes uncertain and the necessity arises to assess Oryza species complexes in Sri Lanka using morphological, anatomical, and molecular information to enumerate number of species within each Oryza complex and characterization of species and species complexes. The study revealed, characterization of wild rice species, to a certain extent, can be made through morphological and anatomical characters, specially lamina anatomical characters. Molecular information is more reliable in delimitation of wild rice species complexes in Sri Lanka. O. rhizomatis and O. eichingeri (CC) are well separated from the rest of wild rice species (AA). Molecular data revealed, O. nivara and O. rufipogon have undergone independent evolution within Sri Lanka. Well separated five wild rice species are existing in Sri Lanka. Studies on ecological resilience of morphological, anatomical, and molecular studies are very useful for species enumeration of wild rice complexes in Sri Lanka. The findings led to conclude that wild rice species in Sri Lanka are “ecological swarms” and represents allopatric or sympatric populations. A comprehensive knowledge on genetic diversity and population structure of wild rice germplasm in Sri Lanka provides useful information to include these locally adapted and evolved wild rice species in rice crop improvement/breeding.

The genus Oligonychus Berlese (Acari, Prostigmata, Tetranychidae): taxonomic assessment and a key to subgenera, species groups, and subgroups

A comprehensive taxonomic assessment of the most agriculturally important and highly diverse spider mite genus, Oligonychus Berlese (Acari: Tetranychidae) was performed. The sub-generic division, species groups, doubtful species, species complexes and the interpretation of a key generic character are discussed. Based on the orientation of the male aedeagus, only two subgenera, namely Oligonychus Berlese (aedeagus downturned) and Reckiella Tuttle & Baker (aedeagus upturned), are valid in the genus Oligonychus. The subgenera Homonychus Wainstein, Metatetranychoides Wainstein, and Wainsteiniella Tuttle & Baker are considered to be synonyms of the subgenus Oligonychus, whereas the subgenus Pritchardinychus Wainstein is proposed as a synonym of the subgenus Reckiella. Moreover, based on female morphological characters, four species groups (coffeae, exsiccator, iseilemae, and peruvianus) and 11 species subgroups (aceris, biharensis, coffeae, comptus, exsiccator, gossypii, iseilemae, peruvianus, pritchardi, smithi, and subnudus) are suggested in the subgenera Oligonychus and Reckiella. Fourteen Oligonychus species are proposed as species inquirendae, and potential cryptic species complexes in the genus Oligonychus are briefly highlighted. It is agreed that the clunal seta h1 is always absent, while the para-anal setae h2 and h3 are always present in the genus Oligonychus. A key to subgenera, species groups, and species subgroups of the genus Oligonychus is provided.

Uncovering Hidden Diversity: Three New Species of the Keratella Genus (Rotifera, Monogononta, Brachionidae) of High Altitude Water Systems from Central Mexico

The correct identification of species is an essential step before any study on biodiversity, ecology or genetics. Keratella is a genus with a predominantly temperate distribution and with several species being endemics or restricted geographically. Its diversity may be underestimated considering the confusing taxonomy of species complexes such as K. cochlearis. In this study, we examined genetic diversity and morphology among some Keratella populations from Mexico in order to determine if these populations represent different species. We analyzed a dataset of previously published and newly generated sequences of the mitochondrial COI gene and the nuclear ITS1 marker. We conducted phylogenetic analyses and applied three methods of species delimitation (ABGD, PTP and GMYC) to identify evolutionary significant units (ESUs) equivalent to species. Morphological analyses were conducted through scanning electron microscope (SEM) and morphometry under a compound microscope. In the present study, three new species Keratella cuitzeiensis sp. nov., Keratella huapanguensis sp. nov., and Keratella albertae sp. nov., are formally described. These species were collected in high-altitude water bodies located in the Central Plateau of Mexico. Combining DNA results through COI and ITS1 molecular markers and morphology it was possible to confirm the identity of the new species.

The holobiont mind: A bridge between 4E cognition and the microbiome

All life on earth is intrinsically linked. At the very foundation of every evolutionary interaction are microorganisms, integral components in the composition of both organisms and ecosystems. The available data and this perspective on the order of life challenge the traditional conception of monogenetic biological individuals, suggesting living beings are actually composite multi-species complexes: holobionts. In the present article, we introduce our perspective on the concept of the holobiont mind, a biogenic conception of cognition compatible with the 4E approach and the holobiont theory. We furthermore expand on the idea of the mind as the emerging product of multi-genomic morphology of a composite animal-agent, in ever-changing interaction with its ecological niche. We thus briefly review recent evidence on the brain–gut–microbiome axis and the Microbiome of the Built Environment in order to provide a bridge between the Holobiont Mind and the 4E approach to Cognition, two complementary lines of evidence that have not been linked before, opening novel venues for research with direct impact on health and disease.

FUSARIUM-ID v.3.0: An updated, downloadable resource for Fusarium species identification

Species within Fusarium are of global agricultural, medical, and food/feed safety concern and have been extensively characterized. However, accurate identification of species is challenging and usually requires DNA sequence data. FUSARIUM-ID (http://isolate.fusariumdb.org/) is a publicly available database designed to support the identification of Fusarium species using sequences of multiple phylogenetically informative loci, especially the highly informative ~680 bp 5' portion of the translation elongation factor 1-alpha (TEF1) gene that has been adopted as the primary barcoding locus in the genus. However, FUSARIUM-ID v.1.0 and 2.0 had several limitations, including inconsistent metadata annotation for the archived sequences and poor representation of some species complexes and marker loci. Here, we present FUSARIUM-ID v.3.0, which provides the following improvements: (i) additional and updated annotation of metadata for isolates associated with each sequence, (ii) expanded taxon representation in the TEF1 sequence database, (iii) availability of the sequence database as a downloadable file to enable local BLAST queries, and (iv) a tutorial file for users to perform local BLAST searches using either freely-available software, such as SequenceServer, BLAST+ executable in the command line, and Galaxy, or the proprietary Geneious software. FUSARIUM-ID will be updated on a regular basis by archiving sequences of TEF1 and other loci from newly identified species and greater in-depth sampling of currently recognized species.