The Complete Genome Resource of Xanthomonas oryzae pv. oryzae CIX2779 Includes the First Sequence of a Plasmid for an African Representative of This Rice Pathogen

The bacterial plant pathogen Xanthomonas oryzae pv. oryzae is responsible for the foliar rice bacterial blight disease. Genetically contrasted, continent-specific, sublineages of this species can cause important damages to rice production both in Asia and Africa. We report on the genome of the CIX2779 strain of this pathogen, previously named NAI1 and originating from Niger. Oxford Nanopore long reads assembly and Illumina short reads polishing produced a genome sequence composed of a 4,725,792-bp circular chromosome and a 39,798-bp-long circular plasmid designated pCIX2779_1. The chromosome structure and base-level sequence are highly related to reference strains of African X. oryzae pv. oryzae and encode identical transcription activator-like effectors for virulence. Importantly, our in silico analysis strongly indicates that pCIX2779_1 is a genuine conjugative plasmid, the first indigenous one sequenced from an African strain of the X. oryzae species. [Graphic: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license

Genomic Instability in Somatic Hybridization between Poncirus and Citrus Species Aiming to Create New Rootstocks

International audienceRootstocks are an important component for citrus adaptation to increasing biotic and abiotic stresses resulting from global climate change. There is a strong complementarity between Citrus species, which adapt to abiotic stresses, and Poncirus trifoliata and its intergeneric hybrids, which exhibit resistances or tolerances to major diseases and pests. Thus, symmetrical somatic hybridization between complementary diploid rootstocks of these two genera appears to be an efficient way to develop new tetraploid rootstocks in order to address the new challenges of the citrus industry. New intergeneric somatic hybrids were obtained by electrofusion between protoplasts of Citrus and P. trifoliata hybrids. Extensive characterization of the nuclear and cytoplasmic genomes was performed by genotyping-by-sequencing (GBS) analysis. This revealed diploid cybrids and nuclear somatic hybrids. Mitochondrial genomes were mostly inherited from the callus parent, but homologous recombination events were observed for one parental combination. Chloroplasts exhibited random uniparental inheritance. GBS revealed local chromosomal instabilities for all nuclear somatic hybrids and whole chromosome eliminations for two hybrids. However, at the whole genome level, symmetrical addition of the nuclear genomes of both parents was predominant and all somatic hybrids displayed at least one trifoliate orange haplotype throughout the genome

Dilute liquid crystals used to enhance residual dipolar couplings may alter conformational equilibrium in oligosaccharides

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Validation of the 2010-ACR/EULAR – classification criteria using newly EULAR-defined erosion for rheumatoid arthritis on the very early arthritis community-based (VErA) cohort

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Morfologia externa dos cicadellinae (homoptera, cicadellidae): comparação entre versigonalia ruficauda (walker) (cicadellini) e tretogonia cribrata melichar (proconiini), com notas sobre outras espécies e análise da terminologia External morphology of the cicadellinae (homoptera, cicadellidae): comparison between versigonalia ruficauda (walker) (cicadellini) and tretogonia cribrata melichar (proconiini), with notes on other species and an analysis of the structural terminology

<abstract language="eng">The external morphology of two cicadelline species, Versigonalia ruficauda (Walker, 1851) (Cicadellini) and Tretogonia cribrata Melichar, 1926 (Proconiini), is analyzed. The head, axillary sclerites, wing venation, female genitalia, and tegumentary processes are described. Notes on other Cicadellini - Amblyscarlidia albofasciata (Walker, 1851), Tettisama quinquemacidata (Germar, 1821), Macugonalia lencomelas (Walker, 1851), and Diedrocephala variegata (Fabricius, 1775) - and Proconiini - Ciccus adspersus (Fabricius, 1803), Homoscarta superciliaris (Jacobi, 1905), Ichthyobelus sp., and Rhaphirrhinus phosphoreus (Linnaeus, 1758) - are added. A technique for dissecting the female genitalia is presented. The facial porlion of head in V. ruficauda, T. cribrata, and remaining species has a large sclerite (frons or postfrontofrons) clearly defined by the frontogenal suture. Below the frons, and separated from it by the epistomal suture, a smaller sclerite is present (clypeus). The identification of these sclerites is based on comparisons with descriptions in the literature of a generalized Pterygota, a Psocoptera, a fossil Hemipteroidea, and other Homoptera. The conclusions about the identities of frons and clypeus corroborate the hypotheses of Hamilton (1981) on the homologies of cephalic areas in Rhynchota. The facial sclerites have modifications related with the xyleniomyzous diet. The frons is swollen, providing a larger area for attachmcnt of cibarial muscles. Other modifications increasing the area of frons are observed in the Proconiini. In C. adspersus its lateral margins are distinctly pronounced and its upper portion has a pair of lateral elevations. In Ichthyobelus sp. and R. phosphoreus the upper part of frons is greatly developed, occupying 4/5 of dorsal area of head on middle line. The vertex is limited to a small portion (1/5) of that area. The clypeus is also swollen, a fact related with the greater development of cibarium. This character is more conspicuous in the Proconiini. In this tribe the clypeus has a convex projection occupied by the cibarium, which is greatly devcloped. The pronotum and forewings in T. cribrata are covered by pits, each with a seta on external margin. These pits are similar (and maybe homologous) to struetures in the abdomen of a membracid (Goniolomus tricomiger Stål. 1869). The pronotum is smooth in V. ruficauda. However, pits similar to those of T. cribrata, although smaller. oceur near the forewing veins. A strong costal vein is present in the forewings of the 10 studied species. This vein is formed by a fusion between precosta (PC), costa anterior (CA), and costa posterior (CP). Vestiges of subcosta posterior (ScP) and media (M) occur in the forewing base. A vein formed by a fusion between anal (A) and jugal (J) veins is observed along the inner margin of clavus. In the hindwings, PC, CA, and CP are also fused. The occurrence of PC can be inferred by the presence of the wing coupling lobe. which represents its final part. Jugal anterior (JA) is fused to anal posterior (AP"). Jugal posterior (JP) occurs as a small rudiment at hindwing base. The characters of fore - and hindwings confirm the observations of Dworakowska (1988) on the Cicadellidae. The presence of PC and J corroborates Kukalová-Peck's (1983) model of the primitive pterygote venation. Comparisons between the Cicadellinae and a description of a fossil species of the order Diaphanopterodea (Kukalová-Peck 1992) revealed remarkable similarities in female genitalia. Such similarities (manifested in the positions of gonocoxites eight and nine, gonangulum, valvulae eight and nine, and lergite nine) permit a correct interpretation of the genital structurcs in the subfamily. The sclerites of the genital chamber described by Young (1977) in females of various Cicadellini are the reduced eighth abdominal sternite. Sclerotized plates in this sternite occur in A. albofasciata, T. quinquemaculata, T. cribrata, C. adspersus, and H. superciliaris. Comparisons carried out among these Cicadellinae, allied with data from the literature, indicate that the eighth sternum can provide useful characters for the subfamily taxonomy. Features of potential taxonomic interest in valvulae eight and nine include tegumentary processes (valvulae eight), shaft form, and teeth form and distribution (valvulae nine). Lists with the terms suggested for head, wings, and female genitalia are included, together with synonyms proposed by other taxonomists and morphologists