种子微生物生态学研究进展

植物种子微生物生态学是研究与种子相联合的微生物的组成﹑功能﹑演替、它们之间关系及其与宿主之间相互关系的科学。种子中蕴含着丰富的微生物资源,它们对种子以及植物的健康具有重要的影响。不同种类植物种子联合的微生物群落由于受到种子本身及外界环境因素的影响而有所差异。论述了种子微生物生态学的概念、主要研究方法、种子微生物生态系统中的微生物种类、相关影响因素,以及种子微生物生态学研究的发展方向。种子微生物生态学的研究对生产实践有重要意义,同时也将丰富种子生物学的内容,对种子科学的发展起到促进作用。     

Multigene Molecular Phylogeny and Biogeographic Diversification of the Earth Tongue Fungi in the Genera Cudonia and Spathularia (Rhytismatales,Ascomycota)

The family Cudoniaceae (Rhytismatales, Ascomycota) was erected to accommodate the “earth tongue fungi” in the genera Cudonia and Spathularia. There have been no recent taxonomic studies of these genera, and the evolutionary relationships within and among these fungi are largely unknown. Here we explore the molecular phylogenetic relationships within Cudonia and Spathularia using maximum likelihood and Bayesian inference analyses based on 111 collections from across the Northern Hemisphere. Phylogenies based on the combined data from ITS, nrLSU, rpb2 and tef-1α sequences support the monophyly of three main clades, the /flavida, /velutipes, and /cudonia clades. The genus Cudonia and the family Cudoniaceae are supported as monophyletic groups, while the genus Spathularia is not monophyletic. Although Cudoniaceae is monophyletic, our analyses agree with previous studies that this family is nested within the Rhytismataceae. Our phylogenetic analyses circumscribes 32 species-level clades, including the putative recognition of 23 undescribed phylogenetic species. Our molecular phylogeny also revealed an unexpectedly high species diversity of Cudonia and Spathularia in eastern Asia, with 16 (out of 21) species-level clades of Cudonia and 8 (out of 11) species-level clades of Spathularia. We estimate that the divergence time of the Cudoniaceae was in the Paleogene approximately 28 Million years ago (Mya) and that the ancestral area for this group of fungi was in Eastern Asia based on the current data. We hypothesize that the large-scale geological and climatic events in Oligocene (e.g. the global cooling and the uplift of the Tibetan plateau) may have triggered evolutionary radiations in this group of fungi in East Asia. This work provides a foundation for future studies on the phylogeny, diversity, and evolution of Cudonia and Spathularia and highlights the need for more molecular studies on collections from Europe and North America.     

The enigmatic monotypic crab plover Dromas ardeola is closely related to pratincoles and coursers (Aves, Charadriiformes, Glareolidae)

The phylogenetic placement of the monotypic crab plover Dromasardeola (Aves, Charadriiformes) remains controversial. Phylogenetic analysis of anatomical and behavioral traits using phenetic and cladistic methods of tree inference have resulted in conflicting tree topologies, suggesting a close association of Dromas to members of different suborders and lineages within Charadriiformes. Here, we revisited the issue by applying Bayesian and parsimony methods of tree inference to 2,012 anatomical and 5,183 molecular characters to a set of 22 shorebird genera (including Turnix). Our results suggest that Bayesian analysis of anatomical characters does not resolve the phylogenetic relationship of shorebirds with strong statistical support. In contrast, Bayesian and parsimony tree inference from molecular data provided much stronger support for the phylogenetic relationships within shorebirds, and support a sister relationship of Dromas to Glareolidae (pratincoles and coursers), in agreement with previously published DNA-DNA hybridization studies.     

Evolutionary history of frogfishes (Teleostei: Lophiiformes: Antennariidae): a molecular approach

Fishes of the family Antennariidae (order Lophiiformes) are primarily shallow-water benthic forms found in nearly all tropical and subtropical oceans and seas of the world, with some taxa extending into temperate waters. Despite an earlier attempt based on morphology, no previous hypothesis of intergeneric relationships of the Antennariidae exists. To resolve phylogenetic relationships within the Antennariidae, and to test the validity of species groups within Antennarius, DNA sequences from the mitochondrial 16S and cytochrome oxidase c subunit 1 (COI) genes, and nuclear recombination activating gene 2 (RAG2), for 25 described and four undescribed antennariid species, representing 10 of 12 known genera and one undescribed genus, were unambiguously aligned and analyzed using Bayesian and maximum likelihood methods. The markers were partitioned and analyzed for substitution saturation and only the third codon position of COI (COI-3) was found to have reached saturation. However, analysis of both datasets, one with the saturated data and one without, differed only slightly. All molecular analyses recovered two major clades, one comprised of Fowlerichthys, Antennarius, Histrio, and Antennatus; and another containing Rhycherus, Antennariidae gen. et sp. nov., Kuiterichthys, Phyllophryne, Echinophryne, Tathicarpus, Lophiocharon, and Histiophryne. Evidence is presented to illustrate a correlation between phylogeny, geographic distribution, and reproductive life history. The results of these analyses provide the first hypothesis of evolutionary relationships within the Antennariidae.     

Computational analysis of evolution and conservation in a protein superfamily

Many gene superfamilies have hundreds or thousands of members and hence pose a significant challenge when performing a large-scale phylogenetic analysis. Derivation of the most accurate alignment possible and inference of evolutionary relationships (with an appropriate measure of confidence) are significant "bottlenecks" in the process. A generally applicable strategy is outlined for identifying and aligning sequences, performing simple analysis of the resulting alignment, and inferring evolutionary relationships. Reference is made to the serpin superfamily. The 'partition cluster' method, a relatively rapid technique for extracting underlying associations from phylogenetic bootstrap trees, is also presented.     

Evolution of syncarpy and other morphological characters in African Annonaceae: a posterior mapping approach

The congenital fusion of carpels, or syncarpy, is considered a key innovation as it is found in more than 80% of angiosperms. Within the magnoliids however, syncarpy has rarely evolved. Two alternative evolutionary origins of syncarpy were suggested in order to explain the evolution of this feature: multiplication of a single carpel vs. fusion of a moderate number of carpels. The magnoliid family Annonaceae provides an ideal situation to test these hypotheses as two African genera, Isolona and Monodora, are syncarpous in an otherwise apocarpous family with multicarpellate and unicarpellate genera. In addition to syncarpy, the evolution of six other morphological characters was studied. Well-supported phylogenetic relationships of African Annonaceae and in particular those of Isolona and Monodora were reconstructed. Six plastid regions were sequenced and analyzed using maximum parsimony and Bayesian inference methods. The Bayesian posterior mapping approach to study character evolution was used as it accounts for both mapping and phylogenetic uncertainty, and also allows multiple state changes along the branches. Our phylogenetic analyses recovered a fully resolved clade comprising twelve genera endemic to Africa, including Isolona and Monodora, which was nested within the so-called long-branch clade. This is the largest and most species-rich clade of African genera identified to date within Annonaceae. The two syncarpous genera were inferred with maximum support to be sister to a clade characterized by genera with multicarpellate apocarpous gynoecia, supporting the hypothesis that syncarpy arose by fusion of a moderate number of carpels. This hypothesis was also favoured when studying the floral anatomy of both genera. Annonaceae provide the only case of a clear evolution of syncarpy within an otherwise apocarpous magnoliid family. The results presented here offer a better understanding of the evolution of syncarpy in Annonaceae and within angiosperms in general.     

Adaptive traits of bark and ambrosia beetle-associated fungi

A phenotype is the expression of interactions between species genotype and environment. We quantified the contributions of ecological and phylogenetic associations to phenotypic variation in Geosmithia fungi. Geosmithia are symbiotic beetle-associated saprotrophs with a range of life histories and host specificities, including obligate nutritional beetle mutualists (ambrosia fungi) and phytopathogens. We hypothesized that: (1) species phenotypes are better explained by their ecology than by their phylogenetic relationships; (2) niche specialization was accompanied by enzymatic capability losses; and (3) ambrosia Geosmithia species have higher nutritional quality and antibiotic capabilities than species with facultative symbioses. Our results confirmed that long-term co-evolved specialists have reduced metabolic breadth in comparison to generalists. Phytopathogenic G. morbida produces unique enzyme suites with affinity to ligno-cellulose. Mycelia of ambrosia fungi contain large amounts of oleic fatty acid with nutritive and possibly allelopathic function. Overall, our results indicate that Geosmithia ecology have greater effect on species phenotype than their phylogenetic relationships.     

Phylogenetic analysis of rust fungi (Uredinales) from the Colombian Andean region using 28S ribosomal DNA sequences

Rust fungi (Uredinales, Basidiomycetes) are one of the most diverse and economically important plant-obligated parasites. Taxonomy of this group has been under revision during the last years using molecular techniques to define phylogenetic relationships. In this study we evaluated the phylogenetic affinities of a group of 40 rust fungi obtained from different plants in the Colombian Andean region using sequence analysis of the 28S ribosomal DNA, specifically D1/D2 domains. Comparisons were undertaken with sequences of rust fungi from around the world deposited in the GenBank database. An alignment of sequences was used to build a phylogenetic tree through Maximum parsimony analysis. Our results support the taxonomical validity of families Pucciniaceae, Phakopsoraceae, Phragmidiaceae, Pileolariaceae, Mikronegeriaceae, Coleosporiaceae and Cronartiaceae, while Pucciniosiraceae represents redundant taxa with Pucciniaceae. The analyses indicated that Uropyxidaceae, Raveneliaceae, Chaconiaceae and Pucciniastraceae correspond to polyphyletic families. Melampsoraceae appear to be a basal taxon to the Uredinales. Information obtained in this study will be useful to incorporate a higher number of sequences from tropical rust fungi within global efforts to redefine the taxonomy of order Uredinales. Additionally, we propose to give priority to future phylogenetic studies of taxa: Gerwasia, Hemileia, Phragmidium, Prospodium, Puccinia and Uromyces, genera that include a high number of rust fungi from the tropics.     

Mitogenomes provide new insights of evolutionary history of Boreheptagyiini and Diamesini (Diptera: Chironomidae: Diamesinae)

Mitogenomes have been widely used for phylogenetic reconstruction of various Dipteran groups, but specifically for chironomid, they have not been carried out to resolve the relationships. Diamesinae (Diptera: Chironomidae) are important bioindicators for freshwater ecosystem monitoring, but its evolutionary history remains uncertain for lack of information. Here, coupled with one previously published and 30 new mitogenomes of Diamesinae, we carried out comparative mitogenomic analysis and phylogenetic analysis. Mitogenomes of Diamesinae were conserved in structure, and all genes arranged in the same order as the ancestral insect mitogenome. All protein‐coding genes in Diamesinae were under stronger purifying selection than those of other nonbiting midge species, which may exhibit signs of adaptation to life at cold living conditions. Phylogenetic analyses strongly supported the monophyly of Diamesinae, with Boreheptagyiini deeply nested within Diamesini. In addition, phylogenetic relationship of selected six genera was resolved, except Sympotthastia remained unstable. Our study revealed that the mitogenomes of Diamesinae are highly conserved, and they are practically useful for phylogenetic inference.     

Multiple evolutionary origins lead to diversity in the metabolic profiles of ambrosia fungi

Ambrosia fungi are an ecological assemblage cultivated by ambrosia beetles as required nutrient sources. This mutualism evolved in multiple beetle and fungus lineages. Whether convergence in ecology led to convergent metabolism in ambrosia fungi is unknown. We compared the assimilation of 190 carbon sources in five independent pairs of ambrosia fungi and closely related, non-ambrosial species. Ecological convergence versus phylogenetic divergence in carbon source use was tested using variation partitioning. We found no convergence in carbon utilization capacities. Instead, metabolic variation was mostly explained by phylogenetic relationships. In addition, carbon usage in ambrosia fungi was equally diverse as that in non-ambrosial species. Thus, carbon metabolism of each ambrosia fungus is determined by its inherited metabolism, not the transition towards symbiosis. In contrast to other fungus-farming systems of termites and attine ants, the fungal symbionts of ambrosia beetles are functionally diverse, reflecting their independent evolutionary origins.     

Selection of Orthologous Genes for Construction of a Highly Resolved Phylogenetic Tree and Clarification of the Phylogeny of Trichosporonales Species

The order Trichosporonales (Tremellomycotina, Basidiomycota) includes various species that have clinical, agricultural and biotechnological value. Thus, understanding why and how evolutionary diversification occurred within this order is extremely important. This study clarified the phylogenetic relationships among Tricosporonales species. To select genes suitable for phylogenetic analysis, we determined the draft genomes of 17 Trichosporonales species and extracted 30 protein-coding DNA sequences (CDSs) from genomic data. The CDS regions of Trichosporon asahii and T. faecale were identified by referring to mRNA sequence data since the intron positions of the respective genes differed from those of Cryptococcus neoformans (outgroup) and are not conserved within this order. A multiple alignment of the respective gene was first constructed using the CDSs of T. asahii, T. faecale and C. neoformans, and those of other species were added and aligned based on codons. The phylogenetic trees were constructed based on each gene and a concatenated alignment. Resolution of the maximum-likelihood trees estimated from the concatenated dataset based on both nucleotide (72,531) and amino acid (24,173) sequences were greater than in previous reports. In addition, we found that several genes, such as phosphatidylinositol 3-kinase TOR1 and glutamate synthase (NADH), had good resolution in this group (even when used alone). Our study proposes a set of genes suitable for constructing a phylogenetic tree with high resolution to examine evolutionary diversification in Trichosporonales. These can also be used for epidemiological and biogeographical studies, and may also serve as the basis for a comprehensive reclassification of pleomorphic fungi.     

A methodological investigation of hominoid craniodental morphology and phylogenetics

The evolutionary relationships of extant great apes and humans have been largely resolved by molecular studies, yet morphology-based phylogenetic analyses continue to provide conflicting results. In order to further investigate this discrepancy we present bootstrap clade support of morphological data based on two quantitative datasets, one dataset consisting of linear measurements of the whole skull from 5 hominoid genera and the second dataset consisting of 3D landmark data from the temporal bone of 5 hominoid genera, including 11 sub-species. Using similar protocols for both datasets, we were able to 1) compare distance-based phylogenetic methods to cladistic parsimony of quantitative data converted into discrete character states, 2) vary outgroup choice to observe its effect on phylogenetic inference, and 3) analyse male and female data separately to observe the effect of sexual dimorphism on phylogenies. Phylogenetic analysis was sensitive to methodological decisions, particularly outgroup selection, where designation of Pongo as an outgroup and removal of Hylobates resulted in greater congruence with the proposed molecular phylogeny. The performance of distance-based methods also justifies their use in phylogenetic analysis of morphological data. It is clear from our analyses that hominoid phylogenetics ought not to be used as an example of conflict between the morphological and molecular, but as an example of how outgroup and methodological choices can affect the outcome of phylogenetic analysis.     

Phylogenetic analysis of Lappula Moench (Boraginaceae) based on molecular and morphological data

Lappula Moench includes ca. 70 species and exhibits a wide range of nutlet variation. Currently, the evolutionary relationships among species of Lappula have not been examined; therefore, to elucidate phylogenetic relationships and morphological evolution within Lappula and related genera, we conducted phylogenetic analyses with matrices that include 48 species as well as four DNA regions (ITS, trnL-trnF, rpS16 and psbA-trnH) and 18 morphological characters. These matrices were analyzed using maximum parsimony, maximum likelihood, and Bayesian inference methods. Analyses of the combined molecular and morphological data result in a phylogeny that is better resolved than that based solely on molecular sequence data. Phylogenetic results suggest that the current infrageneric classification of Lappula, at least at the subsectional and series level, is artificial. The evolutionary patterns of 18 morphological characters are investigated in a phylogenetic context. In Lappula, nutlet homomorphism and small corollas are resolved as ancestral, while nutlet heteromorphism and larger corollas are derived.     

The tropical African legume Scorodophloeus clade includes two undescribed Hymenostegia segregate genera and Micklethwaitia,a rare,monospecific genus from Mozambique

Legume subfamily Caesalpinioideae accommodates approximately 2250 species in 171 genera which traditionally are placed in four tribes: Caesalpinieae, Cassieae, Cercideae and Detarieae. The monophyletic tribe Detarieae includes the Amherstieae subclade which contains about 55 genera. Our knowledge of the relationships among those genera is good in some cases but for many other genera phylogenetic relationships have been unclear. The non-monophyletic nature of at least two amherstioid genera, Cynometra and Hymenostegia has also complicated the picture. During the course of a multi-disciplinary study of Hymenostegia sensu lato, which includes phylogenetic analyses based on matK and trnL data, we have recovered the “Scorodophloeus clade”, an exclusively tropical African clade of four genera which includes the eponymous genus Scorodophloeus, two undescribed generic segregates of Hymenostegia sensu lato, and the previously unsampled rare monospecific genus Micklethwaitia from Mozambique. Zenkerella is suggested as a possible sister genus to the Scorodophloeus clade. A distribution map is presented of the seven species that belong to the Scorodophloeus clade.     

Phylogenetic reconstruction of endophytic fungal isolates using internal transcribed spacer 2 (ITS2) region

Endophytic fungi are inhabitants of plants, living most part of their lifecycle asymptomatically which mainly confer protection and ecological advantages to the host plant. In this present study, 48 endophytic fungi were isolated from the leaves of three medicinal plants and characterized based on ITS2 sequence – secondary structure analysis. ITS2 secondary structures were elucidated with minimum free energy method (MFOLD version 3.1) and consensus structure of each genus was generated by 4SALE. ProfDistS was used to generate ITS2 sequence structure based phylogenetic tree respectively. Our elucidated isolates were belonging to Ascomycetes family, representing 5 orders and 6 genera. Colletotrichum/Glomerella spp., Diaporthae/Phomopsis spp., and Alternaria spp., were predominantly observed while Cochliobolus sp., Cladosporium sp., and Emericella sp., were represented by singletons. The constructed phylogenetic tree has well resolved monophyletic groups with >50% bootstrap value support. Secondary structures based fungal systematics improves not only the stability; it also increases the precision of phylogenetic inference. Above ITS2 based phylogenetic analysis was performed for our 48 isolates along with sequences of known ex-types taken from GenBank which confirms the efficiency of the proposed method. Further, we propose it as superlative marker for reconstructing phylogenetic relationships at different taxonomic levels due to their lesser length.     

Phylogeny of Indo‐West Pacific pontoniine shrimps (Crustacea: Decapoda: Caridea) based on multilocus analysis

The phylogenetic relationships and evolutionary processes within the subfamily Pontoniinae, a speciose group of shrimps with diverse lifestyles (free living, semi‐symbiotic and symbiotic) inhabiting the coral reefs of tropical oceans, are an interesting and undeveloped subject of study. In this work, two mitochondrial ribosomal genes (12S rRNA and 16S rRNA) and two protein‐coding nuclear genes (Histone 3 and the sodium–potassium ATPase α‐subunit) were employed to reconstruct the phylogenetic relationships of 42 genera and 101 species within Pontoniinae. Compared to previous studies, ten additional genera were shown to be monophyletic groups, and the genera Dactylonia and Periclimenaeus were shown to be paraphyletic. The shallow‐water crinoid‐associated pontoniines were divided into several groups which were mostly consistent with the morphological analysis. The studied bivalve‐associated taxa exhibited ancestries that were traceable to different lineages, and two groups could be distinguished: Anchiopontonia + Conchodytes and Anchistus. The similar situation occurred in other echinoderm‐associated pontoniines. These results suggest that pontoniines sharing the same hosts may have different evolutionary origins resulting from multiple intrusions of their hosts by morphologically plastic ancestral groups.     

Molecular characterization of a phosphoserine aminotransferase gene in Antheraea pernyi and assessment of its value for phylogenetic inference

A gene encoding phosphoserine aminotransferase from Antheraea pernyi (ApPSAT) was isolated and characterized, and its value for phylogenetic inference was assessed. The resulting 1309 bp cDNA sequence contains an open reading frame of 1095 bp encoding a polypeptide of 364 amino acids, with 58% sequence identity to that from Homo sapiens. RT-PCR analysis showed that the ApPSAT gene was transcribed at four developmental stages, and in all examined tissues with the most abundance in malpighian tubules. Sequence alignment suggested that ApPSAT protein sequence exhibited 41–87% homology with the known PSATs from bacteria, fungi, plants, invertebrates and vertebrates. Phylogenetic analysis revealed that 37 representative PSAT protein sequences were well divided into five groups corresponding to the known fungi, bacteria, plants, invertebrates and vertebrates. The phylogenetic relationships obtained were consistent with the traditional classification and other molecular data, suggesting the potential value of the PSAT protein in phylogenetic inference.     

Dactylogyridae 2022: a meta-analysis of phylogenetic studies and generic diagnoses of parasitic flatworms using published genetic and morphological data

Dactylogyridae is one of the most studied families of parasitic flatworms with more than 1000 species and 166 genera described to date including ecto- and endoparasites. Dactylogyrid monogeneans were suggested as model organisms for host-parasite macroevolutionary and biogeographical studies due to the scientific and economic importance of some of their host lineages. Consequently, an array of phylogenetic research into different dactylogyrid lineages has been produced over the past years but the last family-wide study was published 16 years ago. Here, we provide a meta-analysis of the phylogenetic relationships of Dactylogyridae including representatives of all genera with available molecular data (n = 67). First, we investigate the systematic informativeness of morphological characters widely used to diagnose dactylogyrid genera through a parsimony analysis of the characters, character mapping, and phylogenetic comparative methods. Second, we provide an overview of the current state of the systematics of the family and its subfamilies, and summarise potentially poly- and paraphyletic genera. Third, we elaborate on the implications of taxonomic, citation, and confirmation bias in past studies. Fourth, we discuss host range, biogeographical, and freshwater-marine patterns. We found two well-supported macroclades which we assigned to the subfamilies Dactylogyrinae and Ancyrocephalinae. These subfamilies further include 16 well-supported clades with only a few synapomorphies that could be deduced from generic diagnoses in the literature. Furthermore, few morphological characters considered systematically informative at the genus level display a strong phylogenetic signal. However, the parsimony analysis suggests that these characters provide little information on the relationships between genera. We conclude that a strong taxonomic bias and low coverage of DNA sequences and regions limit knowledge on morphological and biogeographical evolutionary patterns that can be inferred from these results. We propose addressing potential citation and confirmation biases through a ‘level playing field’ multiple sequence alignment as provided by this study.     

Phylogenetic reassessment of Hyaloscyphaceae sensu lato (Helotiales, Leotiomycetes) based on multigene analyses

Hyaloscyphaceae is the largest family in Helotiales, Leotiomycetes. It is mainly characterized by minute apothecia with well-differentiated hairs, but its taxonomic delimitation and infrafamilial classification remain ambiguous. This study performed molecular phylogenetic analyses using multiple genes including the ITS-5.8S rDNA, the D1–D2 region of large subunit of rDNA, RNA polymerase II subunit 2, and the mitochondrial small subunit. The primary objective was to evaluate the phylogenetic utility of morphological characters traditionally used in the taxonomy of Hyaloscyphaceae through reassessment of the monophyly of this family and its genera. The phylogenetic analyses inferred Hyaloscyphaceae as being a heterogeneous assemblage of a diverse group of fungi and not supported as monophyletic. Among the three tribes of Hyaloscyphaceae only Lachneae formed a monophyletic lineage. The presence of hairs is rejected as a synapomorphy, since morphologically diversified hairs have originated independently during the evolution of Helotiales. The true- and false-subiculum in Arachnopezizeae are hypothesized to have evolved through different evolutionary processes; the true-subiculum is likely the product of a single evolutionary origin, while the false-subiculum is hypothesized to have originated multiple times. Since Hyaloscyphaceae sensu lato was not resolved as monophyletic, Hyaloscyphaceae sensu stricto is redefined and only applied to the genus Hyaloscypha.