Subgenome phasing for complex allopolyploidy: case-based benchmarking and recommendations.

Accurate subgenome phasing is crucial for understanding the origin, evolution and adaptive potential of polyploid genomes. SubPhaser and WGDI software are two common methodologies for subgenome phasing in allopolyploids, particularly in scenarios lacking known diploid progenitors. Triggered by a recent debate over the subgenomic origins of the cultivated octoploid strawberry, we examined four well-documented complex allopolyploidy cases as benchmarks, to evaluate and compare the accuracy of the two software. Our analysis demonstrates that the subgenomic structure phased by both software is in line with prior research, effectively tracing complex allopolyploid evolutionary trajectories despite the limitations of each software. Furthermore, using these validated methodologies, we revisited the controversial issue regarding the progenitors of the octoploid strawberry. The results of both methodologies reaffirm Fragaria vesca and Fragaria iinumae as progenitors of the octoploid strawberry. Finally, we propose recommendations for enhancing the accuracy of subgenome phasing in future studies, recognizing the potential of integrated tools for advanced complex allopolyploidy research and offering a new roadmap for robust subgenome-based phylogenetic analysis.

High-quality genome assembly enables prediction of allele-specific gene expression in hybrid poplar.

Poplar (Populus) is a well-established model system for tree genomics and molecular breeding, and hybrid poplar is widely used in forest plantations. However, distinguishing its diploid homologous chromosomes is difficult, complicating advanced functional studies on specific alleles. In this study, we applied a trio-binning design and PacBio high-fidelity long-read sequencing to obtain haplotype-phased telomere-to-telomere genome assemblies for the 2 parents of the well-studied F1 hybrid "84K" (Populus alba × Populus tremula var. glandulosa). Almost all chromosomes, including the telomeres and centromeres, were completely assembled for each haplotype subgenome apart from 2 small gaps on one chromosome. By incorporating information from these haplotype assemblies and extensive RNA-seq data, we analyzed gene expression patterns between the 2 subgenomes and alleles. Transcription bias at the subgenome level was not uncovered, but extensive-expression differences were detected between alleles. We developed machine-learning (ML) models to predict allele-specific expression (ASE) with high accuracy and identified underlying genome features most highly influencing ASE. One of our models with 15 predictor variables achieved 77% accuracy on the training set and 74% accuracy on the testing set. ML models identified gene body CHG methylation, sequence divergence, and transposon occupancy both upstream and downstream of alleles as important factors for ASE. Our haplotype-phased genome assemblies and ML strategy highlight an avenue for functional studies in Populus and provide additional tools for studying ASE and heterosis in hybrids.

Genomic analyses provide insights into sex differentiation of tetraploid strawberry (Fragaria moupinensis).

The strawberry genus, Fragaria, exhibits a wide range of sexual systems and natural ploidy variation. Nearly, all polyploid strawberry species exhibit separate sexes (dioecy). Research has identified the sex-determining sequences as roughly conserved but with repeatedly changed genomic locations across octoploid strawberries. However, it remains unclear whether tetraploid wild strawberries evolved dioecy independently or shared a common origin with octoploid strawberries. In this study, we investigated the sex determinants of F. moupinensis, a dioecious plant with heterogametic females (ZW). Utilizing a combination of haplotype-resolved genome sequencing of the female F. moupinensis, k-mer-based and coverage-based genome-wide association studies (GWAS), and transcriptomic analysis, we discovered a non-recombining, approximately 33.6 kb W-specific region on chromosome 2a. Within this region, only one candidate sex-determining gene (FmoAFT) was identified. Furthermore, an extensive resequencing of the entire Fragaria genus indicated that the W-specific region displays conservative female specificity across all tetraploid species. This observation suggests that dioecy evolved independently in tetraploid and octoploid strawberries. Moreover, employing virus-induced gene silencing (VIGS), we knocked down the expression of the FmoAFT homologue transcript in cultivated strawberries, revealing its potential role in promoting female functions during early carpel development. We also applied DNA affinity purification sequencing (DAP-seq) and yeast one-hybrid assays to identify potential direct targets of FmoAFT. These insights shed new light on the genetic basis and evolutionary history of sex determination in strawberries, thereby facilitating the formulation of strategies to manipulate sex determination in breeding programs.

Gap-free X and Y chromosome assemblies of Salix arbutifolia reveal an evolutionary change from male to female heterogamety in willows, without a change in the position of the sex-determining locus.

In the Vetrix clade of Salix, a genus of woody flowering plants, sex determination involves chromosome 15, but an XY system has changed to a ZW system. We studied the detailed genetic changes involved. We used genome sequencing, with chromosome conformation capture (Hi-C) and PacBio HiFi reads to assemble chromosome level gap-free X and Y of Salix arbutifolia, and distinguished the haplotypes in the 15X- and 15Y-linked regions, to study the evolutionary history of the sex-linked regions (SLRs). Our sequencing revealed heteromorphism of the X and Y haplotypes of the SLR, with the X-linked region being considerably larger than the corresponding Y region, mainly due to accumulated repetitive sequences and gene duplications. The phylogenies of single-copy orthogroups within the SLRs indicate that S. arbutifolia and Salix purpurea share an ancestral SLR within a repeat-rich region near the chromosome 15 centromere. During the change in heterogamety, the X-linked region changed to a W-linked one, while the Z was derived from the Y.

Chromosome-level genome assembly and population genetic analysis of a critically endangered rhododendron provide insights into its conservation.

Rhododendrons are woody plants, famous throughout the world as having high horticultural value. However, many wild species are currently threatened with extinction. Here, we report for the first time a high-quality, chromosome-level genome of Rhododendron griersonianum, which has contributed to approximately 10% of all horticultural rhododendron varieties but which in its wild form has been evaluated as critically endangered. The final genome assembly, which has a contig N50 size of approximately 34 M and a total length of 677 M, is the highest-quality genome sequenced within the genus to date, in part due to its low heterozygosity (0.18%). Identified repeats constitute approximately 57% of the genome, and 38 280 protein-coding genes were predicted with high support. We further resequenced 31 individuals of R. griersonianum as well as 30 individuals of its widespread relative R. delavayi, and performed additional conservation genomic analysis. The results showed that R. griersonianum had lower genetic diversity (θ = 2.58e-3; π = 1.94e-3) when compared not only to R. delavayi (θ = 11.61e-3, π = 12.97e-3), but also to most other woody plants. Furthermore, three severe genetic bottlenecks were detected using both the Stairway plot and fastsimcoal2 analysis, which are thought to have occurred in the late Middle Pleistocene and the Last Glacial Maximum (LGM) period. After these bottlenecks, R. griersonianum recovered and maintained a constant effective population size (>25 000) until now. Intriguingly, R. griersonianum has accumulated significantly more deleterious mutations in the homozygous state than R. delavayi, and several deleterious mutations (e.g., in genes involved in the response to heat stress) are likely to have harmed the adaptation of this plant to its surroundings. This high-quality, chromosome-level genome and the population genomic analysis of the critically endangered R. griersonianum will provide an invaluable resource as well as insights for future study in this species to facilitate conservation and in the genus Rhododendron in general.

SubPhaser: a robust allopolyploid subgenome phasing method based on subgenome-specific k-mers.

With advanced sequencing technology, dozens of complex polyploid plant genomes have been characterized. However, for many polyploid species, their diploid ancestors are unknown or extinct, making it impossible to unravel the subgenomes and genome evolution directly. We developed a novel subgenome-phasing algorithm, SubPhaser, specifically designed for a neoallopolyploid or a homoploid hybrid. SubPhaser first searches for the subgenome-specific sequence (k-mer), then assigns homoeologous chromosomes into subgenomes, and further provides tools to annotate and investigate specific sequences. SubPhaser works well on neoallopolyploids and homoploid hybrids containing subgenome-specific sequences like wheat, but fails on autopolyploids lacking subgenome-specific sequences like alfalfa, indicating that SubPhaser can phase neoallopolyploid/homoploid hybrids with high accuracy, sensitivity and performance. This highly accurate, highly sensitive, ancestral data free chromosome phasing algorithm, SubPhaser, offers significant application value for subgenome phasing in neoallopolyploids and homoploid hybrids, and for the subsequent exploration of genome evolution and related genetic/epigenetic mechanisms.

Demographic history and identification of threats revealed by population genomic analysis provide insights into conservation for an endangered maple.

Recent advancements in whole genome sequencing techniques capable of covering nearly all the nucleotide variations of a genome would make it possible to set up a conservation framework for threatened plants at the genomic level. Here we applied a whole genome resequencing approach to obtain genome-wide data from 105 individuals sampled from the 10 currently known extant populations of Acer yangbiense, an endangered species with fragmented habitats and restricted distribution in Yunnan, China. To inform meaningful conservation action, we investigated what factors might have contributed to the formation of its extremely small population sizes and what threats it currently suffers at a genomic level. Our results revealed that A. yangbiense has low genetic diversity and comprises different numbers of genetic groups based on neutral (seven) and selected loci (13), with frequent gene flow between populations. Repeated bottleneck events, particularly the most recent one occurring within ~10,000 years before present, which decreased its effective population size (Ne ) < 200, and severe habitat fragmentation resulting from anthropogenic activities as well as a biased gender ratio of mature individuals in its natural habitat, might have together contributed to the currently fragmented and endangered status of A. yangbiense. The species has suffered from inbreeding and deleterious mutation load, both of which varied among populations but had similar patterns; that is, populations with higher FROH (frequency of runs of homozygosity) always carried a larger number of deleterious mutations in the homozygous state than in populations with lower FROH. In addition, based on our genetic differentiation results, and the distribution patterns of homozygous deleterious mutations in individuals, we recommend certain conservation actions regarding the genetic rescue of A. yangbiense. Overall, our study provides meaningful insights into the conservation genetics and a framework for the further conservation for the endangered A. yangbiense.

Cultivated hawthorn (Crataegus pinnatifida var. major) genome sheds light on the evolution of Maleae (apple tribe).

Cultivated hawthorn (Crataegus pinnatifida var. major) is an important medicinal and edible plant with a long history of use for health protection in China. Herein, we provide a de novo chromosome-level genome sequence of the hawthorn cultivar "Qiu Jinxing." We assembled an 823.41 Mb genome encoding 40 571 genes and further anchored the 779.24 Mb sequence into 17 pseudo-chromosomes, which account for 94.64% of the assembled genome. Phylogenomic analyses revealed that cultivated hawthorn diverged from other species within the Maleae (apple tribe) at approximately 35.4 Mya. Notably, genes involved in the flavonoid and triterpenoid biosynthetic pathways have been significantly amplified in the hawthorn genome. In addition, our results indicated that the Maleae share a unique ancient tetraploidization event; however, no recent independent whole-genome duplication event was specifically detected in hawthorn. The amplification of non-specific long terminal repeat retrotransposons contributed the most to the expansion of the hawthorn genome. Furthermore, we identified two paleo-sub-genomes in extant species of Maleae and found that these two sub-genomes showed different rearrangement mechanisms. We also reconstructed the ancestral chromosomes of Rosaceae and discussed two possible paleo-polyploid origin patterns (autopolyploidization or allopolyploidization) of Maleae. Overall, our study provides an improved context for understanding the evolution of Maleae species, and this new high-quality reference genome provides a useful resource for the horticultural improvement of hawthorn.

Genome-wide analysis of butterfly bush (Buddleja alternifolia) in three uplands provides insights into biogeography, demography and speciation.

Understanding processes that generate and maintain large disjunctions within plant species can provide valuable insights into plant diversity and speciation. The butterfly bush Buddleja alternifolia has an unusual disjunct distribution, occurring in the Himalaya, Hengduan Mountains (HDM) and the Loess Plateau (LP) in China. We generated a high-quality, chromosome-level genome assembly of B. alternifolia, the first within the family Scrophulariaceae. Whole-genome re-sequencing data from 48 populations plus morphological and petal colour reflectance data covering its full distribution range were collected. Three distinct genetic lineages of B. alternifolia were uncovered, corresponding to Himalayan, HDM and LP populations, with the last also differentiated morphologically and phenologically, indicating occurrence of allopatric speciation likely to be facilitated by geographic isolation and divergent adaptation to distinct ecological niches. Moreover, speciation with gene flow between populations from either side of a mountain barrier could be under way within LP. The current disjunctions within B. alternifolia might result from vicariance of a once widespread distribution, followed by several past contraction and expansion events, possibly linked to climate fluctuations promoted by the Kunlun-Yellow river tectonic movement. Several adaptive genes are likely to be either uniformly or diversely selected among regions, providing a footprint of local adaptations. These findings provide new insights into plant biogeography, adaptation and different processes of allopatric speciation.

Effects of mirror therapy on phantom limb sensation and phantom limb pain in amputees: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the effects of mirror therapy on phantom limb sensation and phantom limb pain in amputees. DATA SOURCES: Nine electronic databases (PubMed, EMBASE, MEDLINE, Web of Science, the Cochrane Library, CINAHL, PsycInfo, PreQuest, PEDro) were searched from their inception to May 10th, 2021. METHODS: Two authors independently selected relevant studies and extracted the data. The effect sizes were calculated under a random-effects model meta-analysis, and heterogeneity was assessed using the I2 test. The risk of bias was evaluated by the Cochrane risk of bias tool, and the methodological quality was appraised by the PEDro scale. The GRADE approach was applied to assess the confidence of the effect. RESULTS: A total of 11 RCTs involving 491 participants were included in this review and nine RCTs involving 372 participants were included in meta-analysis. The quality of these studies was from poor to good with scores ranging from 2 to 8 points according to PEDro scale. The pooled SMD showed that mirror therapy reduced the pain with a large effect size (-0.81; 95% CI = -1.36 to -0.25; P = 0.005; I2 = 82%; n = 372) compared with other methods (four covered mirror, one phantom exercise, three mental visualization, one sensorimotor exercise, one transcutaneous electrical nerve stimulation, one tactile stimuli). The quality of evidence for the outcome pain intensity was determined to be fair according to GRADE approach. CONCLUSION: There is fair-quality evidence that MT is beneficial for reducing phantom limb pain.

Sphingomonas floccifaciens sp. nov., isolated from subterranean sediment.

A Gram-stain-negative, non-motile, non-sporulating, rod-shaped, orange-pigmented bacterium, designated strain FQM01T, was isolated from a subterranean sediment sample in the Mohe permafrost area, China. Strain FQM01T grew optimally at 25 °C, pH 7.0 and NaCl concentration of 0 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain FQM01T belonged to the genus Sphingomonas. The closest phylogenetic relative was Sphingomonas spermidinifaciens GDMCC 1.657T (97.6 %), followed by Sphingomonas mucosissima DSM 17494T (97.2 %). The DNA G+C content of the isolate was 66.9 mol%. Strain FQM01T contained Q-10 as the predominant ubiquinone, and C18 : 1ω6c and/or C18 : 1ω7c, C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, C14 : 0 2-OH and C18 : 1ω7c 11 methyl as the major fatty acids. Major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified glycolipid. Only sym-homospermidine was detected as the polyamine. On the basis of phylogenetic and phenotypic data, strain FQM01T is considered to represent a novel species of Sphingomonas for which the name Sphingomonasfloccifaciens sp. nov. is proposed. The type strain is FQM01T (=CGMCC 1.15797T=KCTC 52630T).

[Treatment of Unilateral Neglect using Repetitive Transcranial Magnetic Stimulation (rTMS) and Sensory Cueing (SC) in Stroke Patients].

OBJECTIVES: To evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) and sensory cueing (SC) for improving hemi-spatial attention deficits related to unilateral neglect, upper limb function and independence of stroke patients. METHODS: An assessor-blinded randomized controlled trial (RCT) was conducted. Eligible stroke patients were treated with rTMS (n =17) or rTMS combined with SC (n =16) in addition to conventional rehabilitation measures. rTMS was applied with low frequency (1 Hz) over the posterior parietal cortex (P5) of the lefthemisphere, 90% resting motor threshold, 900 pulses each session, one session per day, and 5 d per week for 2 weeks. SC was emitted using a wristwatch device attached to the hemiplegic arm for 2 weeks with a cumulative wear time of 3 h per day. The severity of unilateral neglect [behavioral inattention test conventional subtests (BITC), Catherine Bergego scale (CBS)], activity of daily living [modified Barthel index (MBI)], and upper limb function [Fugl-Meyer assessment (FMA), action research arm test (ARAT)] of the patients were measured pre- and post-interventions (immediately after 2 weeks' treatment) by an occupational therapist. RESULTS: BIT-C was relieved significantly over time in both groups. But rTMS+SC had greater improvement than rTMS alone (P <0.05). No significant differences was found between the two groups in other outcomes (CBS, FMA, ARAT). CONCLUSION: rTMS combined with SC is better than rTMS alone for treating unilateral neglect in stroke patients.

Tianweitania sediminis gen. nov., sp. nov., a member of the family Phyllobacteriaceae, isolated from subsurface sediment core.

A bacterial strain, designated Z8T, was isolated from the terrestrial sediment of the Mohe Basin in north-east China. Phylogenetic analyses of 16S rRNA genes showed that this strain belonged to the family Phyllobacteriaceae, and was most closely related to Phyllobacterium bourgognense, with a sequence similarity of 96.9 %. The major cellular fatty acids were summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The major respiratory quinone was ubiquinone-10. The three major polar lipids of strain Z8T consisted of glycolipids, phosphatidylethanolamine and phosphatidylmethylethanolamine. The DNA G+C content was 59.6 mol%. The chemotaxonomic characteristics of strain Z8T differed in some respects from those of members of the family Phyllobacteriaceae. Based on phylogenetic, phenotypic and chemotaxonomic data, strain Z8T is considered to represent a novel species of a novel genus within the family Phyllobacteriaceae, for which the name Tianweitania sediminis gen. nov., sp. nov. is proposed. The type strain is Z8T ( = CGMCC 1.12944T = JCM 30358T).

Altererythrobacter buctense sp. nov., isolated from mudstone core.

A yellow-pigmented, Gram-negative, non-flagellated, rod-shaped bacterial strain, designated M0322(T), was isolated from a mudstone core sample of the Mohe Basin, China. Growth of strain M0322(T) was observed at 15-40 °C (optimum, 30 °C), at pH 5.0-10.0, (optimum, pH 6.0-7.0) and in the presence 0-4 % NaCl (optimum, 0 %). Phylogenetic analyses of 16S rRNA gene sequences revealed that strain M0322(T) formed a distinct phyletic lineage with the members of the genus Altererythrobacter and is closely related to Altererythrobacter aestuarii JCM 16339(T) (96.1 %) and Altererythrobacter namhicola JCM 16345(T) (95.7 %). The only isoprenoid quinone was identified as ubiquinone 10 (Q-10), major polar lipids were determined to be phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified glycolipid and three unidentified phospholipids, while major cellular fatty acids were summed feature 8 (C18:1 ω6c and/or C18:1 ω7c), summed feature 3 (C16:1 ω6c and/or C16:1 ω7c) and 11-Methyl C18:1 ω7c. The DNA G+C content of strain M0322(T) was determined to be 64.6 mol%. Based on the results of the polyphasic taxonomic study, strain M0322(T) is considered to represent a novel species of the genus Altererythrobacter, for which the name Altererythrobacter buctense sp. nov. is proposed. The type strain is M0322(T) (=CGMCC 1.12871(T) = JCM 30112(T)).

Description of Sphingomonas mohensis sp. nov., Isolated from Sediment.

An aerobic, gram-reaction-negative, rod-shaped bacterium, designated strain Z6(T), was isolated from sediment collected at Mohe Basin, China. And its taxonomic position was investigated by applying a polyphasic approach. Growth occurs at 10-45 °C (optimum, 30 °C), at pH 6.0-11.0 (optimum, pH 7.0) and in the presence of 0-3.0 % (w/v) NaCl (optimum, 0 %). The polar lipid profile of strain Z6(T) revealed the presence of diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid and two unidentified phospholipids, and the major quinone was Q-10. The major fatty acids were C18:1 ω7c and/or C18:1 ω6c (summed feature 8) and C16:1 ω6c and/or C16:1 ω7c (summed feature 3). The predominant polyamine was homospermidine. The DNA G + C content of strain Z6(T) is 65.2 mol%. On the basis of the polyphasic evidence presented, strain Z6(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas mohensis sp. nov. is proposed. The type strain is Z6(T) (=CGMCC 1.12891(T) = JCM 19983(T)).

Dyadobacter sediminis sp. nov., isolated from a subterranean sediment sample.

A Gram-reaction-negative, flexirubin-type-pigmented, rod-shaped, aerobic, non-motile bacterium, designated strain Z12(T), was isolated from a subsurface sediment sample. In a phylogenetic tree based on 16S rRNA gene sequences, strain Z12(T) formed a distinct clade with the members of the genus Dyadobacter (<96.7 % sequence similarity). The G+C content of genomic DNA was 45.4 %. The major fatty acids of strain Z12(T) were iso-C15 : 0, C16 : 1ω6c and/or C16 : 1ω7c (summed feature 3) and anteiso-C17 : 1 B and/or iso-C17 : 1 I (summed feature 4). The major respiratory quinone was MK-7 and the major polar lipid was phosphatidylethanolamine. On the basis of phenotypic, phylogenetic and genotypic features, strain Z12(T) is considered to represent a novel species, for which the name Dyadobacter sediminis sp. nov., is proposed. The type strain is Z12(T) ( = JCM 30073(T) = CGMCC 1.12895(T)).

Moheibacter sediminis gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from sediment, and emended descriptions of Empedobacter brevis, Wautersiella falsenii and Weeksella virosa.

A Gram-reaction-negative, yellow-pigmented, strictly aerobic bacterium, designated M0116T, was isolated from the sediment of the Mohe Basin in north-east China. Flexirubin-type pigments were produced. Cells were catalase- and oxidase-positive and non-gliding rods. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain M0116T was a member of the family Flavobacteriaceae and was most closely related to members of the genera Empedobacter, Wautersiella and Weeksella with 90.5-91.0% sequence similarities. The major cellular fatty acids were iso-C15:0 and iso-C17:0 3-OH. The major respiratory quinone was MK-6 and the major polar lipid was phosphatidylethanolamine. The DNA G+C content was 38.2 mol%. Based on phenotypic, phylogenetic and genotypic data, strain M0116T is considered to represent a novel species of a new genus in the family Flavobacteriaceae, for which the name Moheibacter sediminis gen. nov., sp. nov. is proposed. The type strain is M0116T (=CGMCC 1.12708T=JCM 19634T). Emended descriptions of Empedobacter brevis, Wautersiella falsenii and Weeksella virosa are also proposed.

Arenimonas maotaiensis sp. nov., isolated from fresh water.

A translucent, white, Gram-reaction-negative, facultatively anaerobic, non-flagellated, slightly curved or curved bacterial strain, designated YT8(T), was isolated from the fresh water of the Maotai section of Chishui River, China. Cells were catalase-positive and oxidase-positive. Phylogenetic analyses of 16S rRNA gene sequences revealed that strain YT8(T) is a member of the genus Arenimonas with similarity to other members of this genus ranging from 93.7 to 95.0 %. The major isoprenoid quinone was ubiquinone 8 (Q-8), major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, two unidentified phospholipids and two unidentified polar lipids, while major fatty acids were iso-C15 : 0, iso-C14 : 0 and anteiso-C15 : 0. The DNA G+C content of strain YT8(T) was 66.6 mol%. On the basis of phenotypic, phylogenetic and genotypic features studied, strain YT8(T) is suggested to represent a novel species of the genus Arenimonas, for which the name Arenimonas maotaiensis sp. nov. is proposed. The type strain is YT8(T) ( = CGMCC 1.12726(T) = JCM 19710(T)).

Description of Chishuiella changwenlii gen. nov., sp. nov., isolated from freshwater, and transfer of Wautersiella falsenii to the genus Empedobacter as Empedobacter falsenii comb. nov.

A Gram-reaction-negative, strictly aerobic, non-pigmented, non-gliding, rod-shaped bacterium, designated strain BY4(T), was isolated from freshwater. Cells were catalase- and oxidase-positive and indole was produced. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain BY4(T) belonged to the family Flavobacteriaceae and showed 91.6-95.9% sequence similarities to the most closely related strains. The major respiratory quinone was MK-6 and the major polar lipid was phosphatidylethanolamine. The major polyamine was homospermidine and the major fatty acids were iso-C(15 : 0), iso-C(17 : 0) 3-OH and summed feature 3 (C(16 : 1)ω7c and/or C(16 : 1)ω6c). The DNA G+C content was 30.0 mol%. On the basis of phenotypic, phylogenetic and genotypic features, strain BY4(T) is suggested to represent a novel species in a new genus within the family Flavobacteriaceae, for which the name Chishuiella changwenlii gen. nov., sp. nov. is proposed. The type strain of this type species is BY4(T) ( = CGMCC 1.12707(T) = JCM 19633(T)). On the basis of data collected from previous and present studies, it is proposed to reclassify Wautersiella falsenii to the genus Empedobacter as the new combination Empedobacter falsenii comb. nov. (type strain NF 993(T) = CCUG 51536(T) = CIP 108861(T)).