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1. Complete chloroplast genome of the marine eelgrass Zostera pacifica (Zosteraceae, Plantae) from Monterey, California

   https://doi.org/10.1128/mra.01189-24  

   Abdulrahman, Sosan; Aguirre, Adilene; Arriaga, Eliana; Avina, Ashley C; Badajos, Angeles; Badillo, Yureni A; Bañuelos, Alexis M; Pulido, Javier; Bucio_Valdovinos, Bet-sua; Champaco, Taliyah; et al (February 2025, Microbiology Resource Announcements)

   Pritchard, Leighton (Ed.)

   ABSTRACT We present the complete chloroplast genome of the eelgrassZostera pacificafrom Monterey, California. The genome is circular and 144,675  bp in length. It consists of 82 protein-coding, 31 transfer RNA, and 8 ribosomal RNA genes and is 99.44%–99.42% similar in nucleotide pairwise identity to the closely related speciesZostera marina. 

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2. Potato virus X : A global potato‐infecting virus and type member of the Potexvirus genus

   https://doi.org/10.1111/mpp.13163  

   Verchot, Jeanmarie (November 2021, Molecular Plant Pathology)

   Abstract TaxonomyPotato virus Xis the type‐member of the plant‐infectingPotexvirusgenus in the familyAlphaflexiviridae. Physical propertiesPotato virus X (PVX) virions are flexuous filaments 460–480 nm in length. Virions are 13 nm in diameter and have a helical pitch of 3.4 nm. The genome is approximately 6.4 kb with a 5′ cap and 3′ poly(A) terminus. PVX contains five open reading frames, four of which are essential for cell‐to‐cell and systemic movement. One protein encodes the viral replicase. Cellular inclusions, known as X‐bodies, occur near the nucleus of virus‐infected cells. HostsThe primary host is potato, but it infects a wide range of dicots. Diagnostic hosts includeDatura stramoniumandNicotiana tabacum. PVX is transmitted in nature by mechanical contact. Useful websitehttps://talk.ictvonline.org/ictv‐reports/ictv_online_report/positive‐sense‐rna‐viruses/w/alphaflexiviridae/1330/genus‐potexvirus 

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3. Organellomic data sets confirm a cryptic consensus on (unrooted) land‐plant relationships and provide new insights into bryophyte molecular evolution

   https://doi.org/10.1002/ajb2.1397  

   Bell, David; Lin, Qianshi; Gerelle, Wesley_K; Joya, Steve; Chang, Ying; Taylor, Z_Nathan; Rothfels, Carl_J; Larsson, Anders; Villarreal, Juan_Carlos; Li, Fay‐Wei; et al (December 2019, American Journal of Botany)

   PremisePhylogenetic trees of bryophytes provide important evolutionary context for land plants. However, published inferences of overall embryophyte relationships vary considerably. We performed phylogenomic analyses of bryophytes and relatives using both mitochondrial and plastid gene sets, and investigated bryophyte plastome evolution. MethodsWe employed diverse likelihood‐based analyses to infer large‐scale bryophyte phylogeny for mitochondrial and plastid data sets. We tested for changes in purifying selection in plastid genes of a mycoheterotrophic liverwort (Aneura mirabilis) and a putatively mycoheterotrophic moss (Buxbaumia), and compared 15 bryophyte plastomes for major structural rearrangements. ResultsOverall land‐plant relationships conflict across analyses, generally weakly. However, an underlying (unrooted) four‐taxon tree is consistent across most analyses and published studies. Despite gene coverage patchiness, relationships within mosses, liverworts, and hornworts are largely congruent with previous studies, with plastid results generally better supported. Exclusion ofRNAedit sites restores cases of unexpected non‐monophyly to monophyly forTakakiaand two hornwort genera. Relaxed purifying selection affects multiple plastid genes in mycoheterotrophicAneurabut notBuxbaumia. Plastid genome structure is nearly invariant across bryophytes, but thetufA locus, presumed lost in embryophytes, is unexpectedly retained in several mosses. ConclusionsA common unrooted tree underlies embryophyte phylogeny, [(liverworts, mosses), (hornworts, vascular plants)]; rooting inconsistency across studies likely reflects substantial distance to algal outgroups. Analyses combining genomic and transcriptomic data may be misled locally for heavilyRNA‐edited taxa. TheBuxbaumiaplastome lacks hallmarks of relaxed selection found in mycoheterotrophicAneura. Autotrophic bryophyte plastomes, includingBuxbaumia, hardly vary in overall structure. 

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4. Mitochondrial genome diversity across the subphylum Saccharomycotina

   https://doi.org/10.3389/fmicb.2023.1268944  

   Wolters, John F.; LaBella, Abigail L.; Opulente, Dana A.; Rokas, Antonis; Hittinger, Chris Todd (November 2023, Frontiers in Microbiology)

   IntroductionEukaryotic life depends on the functional elements encoded by both the nuclear genome and organellar genomes, such as those contained within the mitochondria. The content, size, and structure of the mitochondrial genome varies across organisms with potentially large implications for phenotypic variance and resulting evolutionary trajectories. Among yeasts in the subphylum Saccharomycotina, extensive differences have been observed in various species relative to the model yeastSaccharomyces cerevisiae, but mitochondrial genome sampling across many groups has been scarce, even as hundreds of nuclear genomes have become available. MethodsBy extracting mitochondrial assemblies from existing short-read genome sequence datasets, we have greatly expanded both the number of available genomes and the coverage across sparsely sampled clades. ResultsComparison of 353 yeast mitochondrial genomes revealed that, while size and GC content were fairly consistent across species, those in the generaMetschnikowiaandSaccharomycestrended larger, while several species in the order Saccharomycetales, which includesS. cerevisiae, exhibited lower GC content. Extreme examples for both size and GC content were scattered throughout the subphylum. All mitochondrial genomes shared a core set of protein-coding genes for Complexes III, IV, and V, but they varied in the presence or absence of mitochondrially-encoded canonical Complex I genes. We traced the loss of Complex I genes to a major event in the ancestor of the orders Saccharomycetales and Saccharomycodales, but we also observed several independent losses in the orders Phaffomycetales, Pichiales, and Dipodascales. In contrast to prior hypotheses based on smaller-scale datasets, comparison of evolutionary rates in protein-coding genes showed no bias towards elevated rates among aerobically fermenting (Crabtree/Warburg-positive) yeasts. Mitochondrial introns were widely distributed, but they were highly enriched in some groups. The majority of mitochondrial introns were poorly conserved within groups, but several were shared within groups, between groups, and even across taxonomic orders, which is consistent with horizontal gene transfer, likely involving homing endonucleases acting as selfish elements. DiscussionAs the number of available fungal nuclear genomes continues to expand, the methods described here to retrieve mitochondrial genome sequences from these datasets will prove invaluable to ensuring that studies of fungal mitochondrial genomes keep pace with their nuclear counterparts. 

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5. Genetic and molecular landscapes of the generalist phytopathogen Botrytis cinerea

   https://doi.org/10.1111/mpp.13404  

   Singh, Ritu; Caseys, Celine; Kliebenstein, Daniel J. (December 2023, Molecular Plant Pathology)

   Abstract Botrytis cinereaPers. Fr. (teleomorph:Botryotinia fuckeliana) is a necrotrophic fungal pathogen that attacks a wide range of plants. This updated pathogen profile explores the extensive genetic diversity ofB. cinerea, highlights the progress in genome sequencing, and provides current knowledge of genetic and molecular mechanisms employed by the fungus to attack its hosts. In addition, we also discuss recent innovative strategies to combatB. cinerea. TaxonomyKingdom: Fungi, phylum: Ascomycota, subphylum: Pezizomycotina, class: Leotiomycetes, order: Helotiales, family: Sclerotiniaceae, genus:Botrytis, species:cinerea. Host rangeB. cinereainfects almost all of the plant groups (angiosperms, gymnosperms, pteridophytes, and bryophytes). To date, 1606 plant species have been identified as hosts ofB. cinerea. Genetic diversityThis polyphagous necrotroph has extensive genetic diversity at all population levels shaped by climate, geography, and plant host variation. PathogenicityGenetic architecture of virulence and host specificity is polygenic using multiple weapons to target hosts, including secretory proteins, complex signal transduction pathways, metabolites, and mobile small RNA. Disease control strategiesEfforts to controlB. cinerea, being a high‐diversity generalist pathogen, are complicated. However, integrated disease management strategies that combine cultural practices, chemical and biological controls, and the use of appropriate crop varieties will lessen yield losses. Recently, studies conducted worldwide have explored the potential of small RNA as an efficient and environmentally friendly approach for combating grey mould. However, additional research is necessary, especially on risk assessment and regulatory frameworks, to fully harness the potential of this technology. 

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