Highest Evolution Rate Research Articles

Laboratory safety and immunogenicity evaluation of live attenuated avian infectious bronchitis GI-23 virus vaccine.

Avian infectious bronchitis virus (IBV) is responsible for a highly contagious disease that poses a significant threat to the poultry industry due to its high rates of evolution. The occurrence of vaccination failure can frequently be attributed to the emergence of novel strains that exhibit antigenic divergence from conventional vaccine strains. This study aims to evaluate the safety and efficacy of the Eg/1212B-based live attenuated virus vaccine indicated for immunization of chickens against nephropathogenic GI-23 variant strains reported globally. Studies were designed in compliance with European Pharmacopeia Ph. Eur. 0442. The attenuated vaccine virus did not exhibit any tendency to revert or increase in virulence after five back-passages in SPF chickens. Ciliostasis scores and kidney lesions (histology) were comparable between vaccinated and control birds. No chicken showed clinical signs of an infection with IBV or died from causes attributable to the vaccine after receiving a 10× overdose. A single vaccination was able to protect the birds in a challenge model with a recent European wild-type IBV strain. The study demonstrated an onset of immunity of 21days and a duration of immunity lasting up to 56days. Vaccination administered individually through the ocular route resulted in a protection rate of 100% to 85%, whereas mass application by spraying offered a protection rate of 85% to 80%. In conclusion, the safety and efficacy data confirm a positive benefit/risk balance, and the investigated product can be considered a suitable vaccine candidate for controlling avian infectious bronchitis nephropathogenic variant strains related to GI-23.

Photocatalytic Oxidative Coupling of Methane to Ethane Using CO2 as a Soft Oxidant over the Au/TiO2-Vo Nanosheets.

Photocatalytic oxidative coupling of methane (OCM) offers an appealing route for converting greenhouse gas into valuable C2 hydrocarbons. However, O2, as the most commonly used oxidant, tends to result in inevitable overoxidation and waste of methane feedstock. Herein, we first report a photocatalytic OCM using CO2 as a soft oxidant for C2H6 production under mild conditions, where an efficient photocatalyst with unique interface sites is designed and constructed to facilitate CO2 adsorption and activation, while concurrently boosting CH4 dissociation. As a prototype, the Au quantum dots anchored on oxygen-deficient TiO2 nanosheets are fabricated, where the Au-Vo-Ti interface sites for CO2 adsorption and activation are collectively disclosed by in situ Kelvin probe force microscopy, quasi in situ X-ray photoelectron spectroscopy and theoretical calculations. Compared with single metal site, the Au-Vo-Ti interface sites exhibit the lower CO2 adsorption energy and decrease the energy barrier of the *CO2 hydrogenation step from 1.05 to 0.77 eV via Au-C and Ti-O dual-site bonding. The adsorbed CO2 on the photocatalyst reduces the energy barrier of *CH4 dissociation to *CH3 from 2.13 to 1.59 eV, contributing to CH4 oxidation. Additionally, in situ Fourier-transform infrared spectroscopy unveils the Au site facilitates ethane production by engaging in *CH3-Au interaction and accelerating CH3-CH3 coupling. Thus, the photocatalyst demonstrates a high C2H6 evolution rate of 2.60 mmol g-1 h-1 for OCM using CO2 as the soft oxidant, surpassing most of previously reported photocatalysts regardless of OCM and nonoxidative coupling of methane. This work highlights the importance of soft oxidants for improving oxidation reaction efficiency and provides atomic scale insight into the design of photocatalysts for CH4 conversion.

Photocatalytic Oxidative Coupling of Methane to Ethane Using CO2 as a Soft Oxidant Over the Au/TiO2‐Vo Nanosheets

Herein, we first report a photocatalytic OCM using CO2 as a soft oxidant for C2H6 production under mild conditions, where an efficient photocatalyst with unique interface sites is constructed to facilitate CO2 adsorption and activation, while concurrently boosting CH4 dissociation. As a prototype, the Au quantum dots anchored on oxygen‐deficient TiO2 nanosheets are fabricated, where the Au‐Vo‐Ti interface sites for CO2 adsorption and activation are collectively disclosed by in situ Kelvin probe force microscopy, quasi in situ X‐ray photoelectron spectroscopy and theoretical calculations. Compared with single metal site, the Au‐Vo‐Ti interface sites exhibit the lower CO2 adsorption energy and decrease the energy barrier of the *CO2 hydrogenation step from 1.05 to 0.77 eV via Au‐C and Ti‐O dual‐site bonding. The adsorbed CO2 reduces the energy barrier of *CH4 dissociation to *CH3 from 2.13 to 1.59 eV, contributing to CH4 oxidation. Additionally, in situ Fourier‐transform infrared spectroscopy unveils the Au site facilitates ethane production by engaging in *CH3‐Au interaction and accelerating CH3‐CH3 coupling. Thus, the photocatalyst demonstrates a high C2H6 evolution rate of 2.60 mmol g‐1 h‐1 for OCM using CO2 as the soft oxidant, surpassing most of previously reported photocatalysts regardless of OCM and nonoxidative coupling of methane.

Comparative Mitogenomics in the Genus Chlorophorus (Coleoptera: Cerambycidae) and Its Phylogenetic Implications

Chlorophorus Chevrolat, 1863, one of the most species-rich genera of Clytini, comprises 36 subgenera and 302 species/subspecies, with some species being of significant economic importance. To assess the monophyly and subgeneric system of this genus, we newly obtained mitochondrial genomic data from 21 species of Chlorophorus via high-throughput sequencing and reconstructed the phylogeny of this genus using ML and BI methods. The mitochondrial genomes of all sequenced Chlorophorus species were found to comprise 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs), and one non-coding region (control region, CR), reflecting a highly conserved gene arrangement. The mitochondrial genomes of the 21 Chlorophorus species range from 15,387 bp to 15,779 bp in length, and all exhibited AT bias. Analysis of the non-synonymous and synonymous substitution rates revealed that ATP8 has the highest evolution rate, whereas COI has the lowest. Further, phylogenetic analyses were performed based on different datasets (13 PCGs + 2 rRNAs, 13 PCGs + 2 rRNAs + 22 tRNAs, PCG123, PCG12) using maximum likelihood (ML) and Bayesian inference (BI) methods. The results indicate that Chlorophorus is monophyletic, but the subgenera Humeromaculatus Özdikmen, 2011; Immaculatoides Özdikmen, 2022; Brevenotatus Özdikmen, 2022; and Chlorophorus (s. str.) Chevrolat, 1863, are not monophyletic. Based on the comparison of male genitalia, we found that the sclerites of the endophallus may exhibit phylogenetic signals for the genus.

Non-noble Metal Single-Molecule Photocatalysts for the Overall Photosynthesis of Hydrogen Peroxide.

Despite the great progress in molecule photocatalytic solar energy conversion, it is particularly challenging to realize a photocatalytic overall reaction in a non-noble metal complex, which represents a new paradigm for photosynthesis. In this study, a class of novel non-noble metal complexes with head-to-tail geometry were designed and readily synthesized via the coordination of triphenylamine-modified 2,2': 6',2″-terpyridine ligands with Zn2+. As expected, these complexes exhibited the desired through-space charge-transfer transition, generating both long-lived excited states (on the order of microseconds) and separate redox centers under visible-light irradiation. These complexes have particularly low exciton binding energies, which make them excellent heterogeneous single molecular photocatalysts for the overall photosynthetic production of H2O2. Remarkably, a high H2O2 evolution rate (8862 μmol g-1 h-1) was achieved in pure H2O under an air atmosphere via precise molecular tailoring, revealing the unparalleled advantages of molecular photocatalysts in improving the catalytic rate of H2O2 production. This is the first time that single-molecule photocatalysts have been used to efficiently complete the photosynthesis of H2O2. This study presents a new paradigm for photocatalytic energy conversion and provides unique insights into the design of molecular photocatalysts.

Mitogenomics Provide New Phylogenetic Insights of the Family Apataniidae (Trichoptera: Integripalpia).

The family Apataniidae consists of two subfamilies, Apataniinae and Moropsychinae. Currently, there are 204 valid species of Apataniidae, which are widely distributed throughout the northern hemisphere. The larvae typically inhabit cold-water environments, and they serve as biological indicators for monitoring the health of freshwater ecosystems. The phylogenetic relationships within Apataniidae are not fully understood. Moreover, the available molecular data of Apataniidae are still limited. Herein, we provided the mitochondrial genomes of eight apataniid species and compared them with the published mitochondrial genomes of Apataniidae. The nine newly obtained sequences ranged from 15,070 bp to 16,737 bp in length. The results of the nonsynonymous with synonymous substitution rates displayed that ATP8 had the highest evolutionary rate, while COXI exhibited the lowest. The ND4L may be an effective molecular marker for the classification of the Apataniidae. Based on the published mitogenomes, we constructed a phylogenetic tree for Limnephiloidea and conducted a preliminary analysis of its advanced phylogeny. The ML and BI analyses recover the monophyly of Apataniidae and Limnephilidae. Except for PCG, BI tree based on other matrices consistently showed the topology: (Apataniana + (Moropsyche + (Apatidelia + Apatania))). The taxonomic status of Apatania and Apatidelia were also preliminarily explored. The mitochondrial genome of Apataniidae provides critical genomic resources for understanding the phylogenetic relationships of Apataniidae.

Evolution: Morphological complexity fuels rapid species turnover.

Some animal lineages, such as mammals or trilobites, show particularly high rates of evolution- that is, of species origination and extinction. What makes such lineages special is not clear. A new study shows that, in fossil ammonoid cephalopods, more complex shell ornaments are associated with higher evolutionary rates.

Ecological drivers of jaw morphological evolution in lepidosaurs.

Ecology is a key driver of morphological evolution during adaptive radiations, but alternative factors like phylogeny and allometry can have a strong influence on morphology. Lepidosaurs, the most diverse clade of tetrapods, including lizards and snakes, have evolved a remarkable variety of forms and adapted to disparate ecological niches, representing an ideal case study to understand drivers of morphological evolution. Here, we quantify morphological variation in the lower jaw using three-dimensional geometric morphometrics on a broad sample of 153 lepidosaur species. Our results suggest that phylogeny has significantly influenced mandibular shape evolution, and snakes have diverged from a lizard-like jaw morphology during their evolution. Allometry and ecological factors like diet, foraging mode and substrate also appear to drive the diversification of mandibular forms. Ecological groups differ in patterns of disparity, convergence and rates of evolution, indicating that divergent evolutionary mechanisms are responsible for the acquisition of different diets and habitats. Our analyses support that lepidosaurs ancestrally use their jaws to capture prey, contrary to the traditional view favouring lingual prehension as ancestral. Specialized or ecologically diverse lineages show high rates of jaw shape evolution, suggesting that morphological innovation in the mandible has contributed to the spectacular ecomorphological diversification of lepidosaurs.

Comparative Evolutionary Epidemiology of SARS-CoV-2 Delta and Omicron Variants in Kuwait.

Continuous surveillance is critical for early intervention against emerging novel SARS-CoV-2 variants. Therefore, we investigated and compared the variant-specific evolutionary epidemiology of all the Delta and Omicron sequences collected between 2021 and 2023 in Kuwait. We used Bayesian phylodynamic models to reconstruct, trace, and compare the two variants' demographics, phylogeographic, and host characteristics in shaping their evolutionary epidemiology. The Omicron had a higher evolutionary rate than the Delta. Both variants underwent periods of sequential growth and decline in their effective population sizes, likely linked to intervention measures and environmental and host characteristics. We found that the Delta strains were frequently introduced into Kuwait from East Asian countries between late 2020 and early 2021, while those of the Omicron strains were most likely from Africa and North America between late 2021 and early 2022. For both variants, our analyses revealed significant transmission routes from patients aged between 20 and 50 years on one side and other age groups, refuting the notion that children are superspreaders for the disease. In contrast, we found that sex has no significant role in the evolutionary history of both variants. We uncovered deeper variant-specific epidemiological insights using phylodynamic models and highlighted the need to integrate such models into current and future genomic surveillance programs.

Clinal variation in autosomal satellite DNA clusters across a contact zone in Barker Frogs.

Contact zones between genetically divergent lineages offer a unique opportunity to explore gene flow and speciation dynamics. Because satellite DNAs (satDNAs) have high evolutionary rates, they may be useful for comparing related taxa and assessing contact zones. Here, we analyzed the distribution of chromosomal clusters of PcP190 satDNA across a contact zone between two distinct genetic lineages of a Neotropical species complex of frogs. The parental lineages, Physalaemus ephippifer and lineage 1B (L1B), exhibited pronounced divergence in the number of PcP190 clusters. We further expanded the geographic scope of this species complex by including two additional Brazilian localities in previously available cytogenetic and mitochondrial DNA datasets. The contact zone exhibited remarkable variation in the chromosomal distribution of PcP190 clusters among the autosomes; the only fixed autosomal site was found on chromosome 3. The highest numbers of PcP190 clusters were observed in specimens collected at sites near (approximately 320 km from) the distribution of L1B, whereas specimens from Dom Eliseu, which is near (approximately 330 km from) the distribution of P. ephippifer, had the lowest numbers of such clusters. Mitochondrial haplotypes also exhibited geographical variation across sites. Our findings expand the known contact zone of these Physalaemus lineages from 1,500 km2 to over 6,200 km2, demonstrating its extensive area, and emphasize the usefulness of satDNAs in studying contact zones.

Dual Near-Infrared-Response S-Scheme Heterojunction with Asymmetric Adsorption Sites for Enhanced Nitrogen Photoreduction.

Photocatalytic nitrogen reduction reaction (PNRR) holds immense promise for sustainable ammonia (NH3) synthesis. However, few photocatalysts can utilize NIR light that carries over 50% of the solar energy for NH3 production with high performance. Herein, a dual NIR-responsive S-scheme ZnCoSx/Fe3S4 heterojunction photocatalyst is designed with asymmetric adsorption sites and excellent PNRR performance. The heterojunction possesses a hollow-on-hollow superstructure: Fe3S4 nanocrystal-modified ZnCoSx nanocages as building blocks assemble into spindle-shaped particles with a spindle-like cavity. Both Fe3S4 and ZnCoSx are NIR active, allowing efficient utilization of full-spectrum light. Moreover, an S-scheme heterojunction is constructed that promotes charge separation. In addition, the Fe/Co dual-metal sites at the interface enable an asymmetric side-on adsorption mode of N2, favoring the polarization and activation of N2 molecules. In combination with the promoted mass transfer and active site exposure of hollow superstructure, a superior PNRR performance is achieved, with a high NH3 evolution rate of 2523.4 µmolg-1h-1, an apparent quantum yield of 9.4% at 400nm and 8% at 1000nm, and a solar-to-chemical conversion efficiency of 0.32%. The work paves the way for the rational design of advanced heterojunction catalysts for PNRR.

Morphological complexity promotes origination and extinction rates in ammonoids

The causes of heterogeneity in evolutionary rates are a key question in macroevolution. Origination and extinction rates are closely related to abiotic factors, such as climate1,2 and geography,3,4 as well as biotic factors such as taxonomic richness5,6 and morphology,7 which are influenced by phylogeny.8,9 Studies on the relationship between morphology and macroevolution have focused on morphological traits, including body size,6,7,9 shape,10 color,11,12 and complexity,13,14,15 and have proposed biological laws, such as the zero-force evolutionary law16 and Cope's rule.17 However, the relationship between morphological complexity and turnover rates remains poorly defined because of the lack of suitable measures for various subjects.18,19 Here, we establish a quantitative method, the two-dimensional ornamentation index (2D-OI), which allows the description of the ornamental complexity of ammonoids. Ammonoids are one of the most abundant and well-studied fossil groups, with complex conch structures.20 Ammonoids display some similarities with trilobites and mammals21,22 in terms of their high evolutionary rates; however, the underlying mechanisms remain elusive. Moreover, ammonoids exhibit marked heterogeneity in turnover rates across spatiotemporal scales23 and clades,23,24 making them key clades for investigating the relationship between turnover rates and morphological complexity. The results show that morphologically complex genera and species often have higher origination and extinction rates than morphologically simple taxa. Diversity fluctuations of taxa with complex ornamentation generally overimprint and control the overall net diversification rates of ammonoids. This double-edged sword of rapid evolution and increased extinction risk driven by complex morphologies has significant implications for our understanding of how species survive over geological timescales.

An updated phylogeography and population dynamics of porcine circovirus 2 genotypes: are they reaching an equilibrium?

Porcine circovirus 2 (PCV2) emerged more than three decades ago as one of the most impactful pathogens in the swine industry. Despite being a DNA virus, one of the hallmarks of PCV2 is its high evolutionary rate, which has led to the emergence of different genotypes, each exhibiting varying degrees of evolutionary success. Current knowledge suggests the occurrence of three main waves of genotype dominance, alternating over time (i.e., PCV2a, PCV2b, and PCV2d), alongside less prevalent genotypes. However, although PCV2d is currently the most common genotype nowadays, the others continue being circulating in the pig population. The present study reconsidered the epidemiological and evolutionary patterns of PCV2 genotypes using phylodynamic analyses, benefiting from an almost 10-fold increase in ORF2 sequence availability compared to previous studies. Additionally, a phylogeographic analysis was performed to investigate viral dispersal patterns and frequency, and the selective pressures acting on the capsid protein were estimated and compared among genotypes. While successive emergence of major genotypes was confirmed, this study extends previous findings by revealing subsequent prevalence fluctuations of PCV2a and PCV2b after their initial decline. This evolutionary process may represent an example of balancing selection, specifically negative frequency-dependent selection, where a genotype fitness diminishes as it becomes more common, and vice versa. Variations in genotype- or clade-specific immunity-affected by the local prevalence of viral groups-combined with the periodic introduction of strains that have independently evolved in different regions, may have led to fluctuations in the population dynamics of major genotypes over time. These fluctuations were associated with ongoing evolution and variations in the capsid amino acid profile. These findings have profound implications for future control strategies. Although PCV2d remains the most prevalent and widespread genotype, other genotypes should not be neglected. Control strategies should thus target the entire PCV2 population, with a focus on fostering broader and more cross-protective immunity.

Construction of COF/COF Organic S-Scheme Heterostructure for Enhanced Overall Water Splitting.

Covalent organic frameworks (COFs) as a new type of photocatalysts have shown unique advantages in visible-light-driven hydrogen evolution, while the reported overall water-splitting systems are still very rare among various COF-based photocatalysts. Herein, two COFs are integrated to construct a type of organic S-scheme heterojunction for improved overall water splitting. In this system, TpBpy-COF and COF-316 serve as H2- and O2-evolving components, respectively, which are combined through π-π interaction between conjugated aromatic rings. By introducing ultra-small Pt nanoparticles (NPs) into the pores of the TpBpy-COF nanosheets (NS), the resultant COF-316/Pt@TpBpy-COF NS heterostructure achieves extremely high H2 and O2 evolution rates of 220.4 and 110.2µmolg-1h-1, respectively, under visible light irradiation (λ ≥ 420nm). The results of transient absorption spectra (TAS) and photoelectronic measurements indicate that the organic heterojunction interface notably facilitates the separation and transfer of photogenerated electron-hole pairs. Further, theoretical calculations and in situ experiments confirm the spontaneous formation of the COF/COF heterojunction interface and the active sites for overall water splitting.

Rapid evolution leads to extensive genetic diversification of cattle flu Influenza D virus

Influenza D virus (IDV), the cattle flu virus, is a novel multi-host RNA virus, circulating silently worldwide, with widespread seropositivity among US cattle, reaching up to 80% in some areas raising a potential threat of cattle-to-human transmission. Currently, five genetic lineages of IDV have been described, but their evolutionary dynamics have not been studied. Although IDV was first identified in 2011, our comprehensive analysis of all known IDV genomes suggests that the earliest ancestors of IDV likely to have evolved towards the end of the 20th century and D/OK lineage appears to have emerged in 2005. We confirmed a significantly higher substitution rate in IDV than in Influenza C virus, which is consistent with their global distribution and multi-host tropism. We identified multiple sub-populations within the D/OK lineage, highlighting extensive diversification and dissemination. Other findings are evidence for potential reassortment among IDV strains in the USA and transboundary circulation of IDV in Europe with introductions into Danish cattle, some of which potentially originated from France. IDV, an emerging virus with a higher rate of evolution and uncontrolled circulation, could facilitate its adaptation to humans. Our findings underscore the importance of targeted surveillance for IDV in humans and at-risk animal populations.

Skull sinuses precluded extinct crocodile relatives from cetacean-style deep diving as they transitioned from land to sea.

During major evolutionary transitions, groups develop radically new body plans and radiate into new habitats. A classic example is cetaceans which evolved from terrestrial ancestors to become pelagic swimmers. In doing so, they altered their air-filled sinuses, transitioning some of these spaces to allow for fluctuations in air capacity and storage via soft tissue borders. Other tetrapods independently underwent land-to-sea transitions, but it is unclear if they similarly changed their sinuses. We use computed tomography to study sinus changes in thalattosuchian crocodylomorphs that transformed from land-bound ancestors to become the only known aquatic swimming archosaurs. We find that thalattosuchian braincase sinuses reduced over their transition, similar to cetaceans, but their snout sinuses counterintuitively expanded, distinct from cetaceans, and that both trends were underpinned by high evolutionary rates. We hypothesize that aquatic thalattosuchians were ill suited to deep diving by their snout sinuses, which seem to have remained large to help drain their unusual salt glands. Thus, although convergent in general terms, thalattosuchians and cetaceans were subject to different constraints that shaped their transitions to water. Thalattosuchians attained a stage similar to less pelagic transitional forms in the cetacean lineage (late protocetid-basilosaurid) but did not become further specialized for ocean life.

Electrochemically activated calcium sulfite for atrazine degradation: Performance, mechanism and kinetics

The conventional use of Na2SO3 in advanced oxidation processes leads to excessive dissolved SO32−, limiting the utilization of oxysulfur species. This study introduced an electrochemically activated CaSO3 (EC-CaSO3) process that exploited the slow-release property of CaSO3. The results showed that the removal ratios of several micropollutants were over 90 % within 10 min, with SO4•− as the primary oxidant. A mathematic model was further developed to simulate the radical conversion, analyze the degradation kinetics and optimize the operational parameters, using atrazine (ATZ) as the target pollutant. The continuous low concentration of SO32− promoted O2 evolution for oxysulfur species transformation and reduced SO4•− quenching. This resulted in 74 % of SO3•− converting to SO5•− and 84 % of SO32− contributing to SO4•− formation. In the initial 2 min, the matched electro-generation of SO3•− and O2 remarkably accelerated SO4•− generation, leading to 82 % removal of ATZ. As electrolysis continued, the reduced release rate of SO32− prevented excessive accumulation of SO32− and maintained high O2 evolution rate to drive SO4•− generation. Consequently, complete degradation of ATZ was achieved within 5 min, with the contribution of SO4•− exceeding 99 %. By investigating the influence of operational parameters on ATZ degradation and energy consumption, the cost-effective conditions (EE/O values < 2.2 kWh/m3/order) occurred at pH above 7, current densities of 60 to 90 A/m2 and initial CaSO3 dosages of 2 to 4 mM. Additionally, density functional calculation and LC-MS analysis confirmed the formation of less toxic intermediates through dealkylation and dechlorination-hydroxylation. These findings suggested that EC-CaSO3 process was a promising technology for oxidizing micropollutants.

Characterization of the complete mitochondrial genomes of four tarantulas (Arachnida: Theraphosidae) with phylogenetic analysis

To better understand the evolution of mitochondrial genomes (mitogenomes) within the family Theraphosidae, we characterized mitogenomes of four tarantulas (Grammostola pulchripes, Phormictopus atrichomatus, Pterinochilus murinus and Pterinopelma sazimai) for the first time. The mitogenomes were all classical circular structures, with lengths ranging from 13,822 bp to 14,011 bp. The constitutive genes and the orientation of the coding strand observed in the four mitogenomes were consistent with those found in other species belonging to the Theraphosidae family. The four mitogenomes were compacted and exhibited a preference for A and T, with the rRNA sequences showing a higher A+T content. Ka/Ks and p-distances analyses showed the ND6 gene had highest evolutionary rate, while the COⅠ gene displayed relatively slower evolution. In contrast to previous phylogenetic studies, our phylogenetic analysis based on mitogenomes provides new phylogenetic relationships among subfamilies. Subfamily Theraphosinae is most closely related to Ornithoctoninae, slightly distant from Harpactirinae, and farthest from Selenocosmiinae. The new data we acquired regarding these mitogenomes will aid in understanding the complex interrelationships among species within the Theraphosidae family.

Characteristics and Comparative Analysis of Six Mitogenomes of Genus Kiefferulus Goetghebuer, 1922 (Diptera: Chironomidae).

Chironomidae is a cosmopolitan and species-rich family of insects, with many species serving as useful indicators of aquatic ecosystem health. In this study, we newly sequenced six species of Kiefferulus Goetghebuer, 1922 (Chironomidae: Chironominae) by high-throughput sequencing technology. We analyzed characters of the mitochondrial genome, including the sequence length, nucleotide composition, and evolutionary rates of this genus. The size of the newly obtained sequences ranged from 15,588 to 15,767 bp, and all of them included 22 tRNAs, 13 PCGs, 2 rRNAs, and 1 CR. The CR showed the highest AT content relative to the PCGs, rRNAs, and tRNAs. Relative synonymous codon usage analysis showed that UUA, UUU, and AUU are the preferred codons. The ratio of nonsynonymous (Ka) to synonymous (Ks) substitution rates showed that all Ka/Ks of PCGs were lower than 1, with ATP8 having the highest evolution rate, while COX1 exhibited the lowest evolution rate. We reconstructed the phylogenetic relationship of the genus Kiefferulus based on eight species (six ingroups and two outgroups), using five matrices and employing Maximum likelihood and Bayesian inference approaches. Phylogenetic analysis of the Kiefferulus showed that six species within this genus were classified into a monophyletic clade.

High rate of gene family evolution in proximity to the origin of ectomycorrhizal symbiosis in Inocybaceae.

The genomes of ectomycorrhizal (ECM) fungi have a reduced number of genes encoding Carbohydrate-Active EnZymes (CAZymes), expansions in transposable elements (TEs) and small secreted proteins (SSPs) compared with saprotrophs. Fewer genes for specific peptidases and lipases in ECM fungi are also reported. It is unclear whether these changes occur at the shift to the ECM habit or are more gradual throughout the evolution of ECM lineages. We generated a genomic dataset of 20 species in the ECM lineage Inocybaceae and compared them with six saprotrophic species. Inocybaceae genomes have fewer CAZymes, peptidases, lipases, secondary metabolite clusters and SSPs and higher TE content than their saprotrophic relatives. There was an increase in the rate of gene family evolution along the branch with the transition to the ECM lifestyle. This branch had very high rate of evolution in CAZymes and had the largest number of contractions. Other significant changes along this branch included expansions in transporters, transposons-related genes and communication genes such as fungal kinases. There is a high concentration of changes in proximity to the transition to the ECM lifestyle, which correspond to the identified key changes for the gain of this lifestyle.