68 research outputs found
Citrus of the world: a Citrus directory
De nombreuses classifications ont tenté de structurer le genre citrus qui constitue un groupe végétal complexe. L'importance des noms locaux, issus de la tradition orale, et plus récemment, l'apparition de dénominations commerciales augmentent encore le nombre des appellations. Cet annuaire représente une tentative d'identification et de standardisation du groupe. Il s'appuie sur la classification très détaillée du Japonais Tanaka, les équivalences avec celle de l'Américain Swingle sont données en annexes. Les tableaux indiquent pour chaque nom rencontré (nom local, appellation commerciale, variante orthographique...) son binôme latin et son nom standardisé. Un synthèse des appellations hybrides complète cet annuair
Cytological and molecular characterization of three gametoclones of Citrus clementina
Abstract
Background
Three gametoclonal plants of Citrus clementina Hort. ex Tan., cv. Nules, designated ESP,
FRA, and ITA (derived from three labs in Spain, France, and Italy, respectively), were
selected for cytological and molecular characterization in order to elucidate genomic
rearrangements provoked by haploidization. The study included comparisons of their ploidy,
homozygosity, genome integrity, and gene dosage, using chromosome counting, flow
cytometry, SSR marker genotyping, and array-Comparative Genomic Hybridization (arrayCGH).
Results
Chromosome counting and flow cytometry revealed that ESP and FRA were haploid, but ITA
was tri-haploid. Homozygous patterns, represented by a single peak (allele), were observed
among the three plants at almost all SSR loci distributed across the entire diploid donor
genome. Those few loci with extra peaks visualized as output from automated sequencing
runs, generally low or ambiguous, might result from amplicons of paralogous members at the
locus, non-specific sites, or unexpected recombinant alleles. No new alleles were found,
suggesting the genomes remained stable and intact during gametogenesis and regeneration.
The integrity of the haploid genome also was supported by array-CGH studies, in which
genomic profiles were comparable to the diploid control.
Conclusions
The presence of few gene hybridization abnormalities, corroborated by gene dosage
measurements, were hypothetically due to the segregation of hemizygous alleles and minor
genomic rearrangements occurring during the haploidization procedure. In conclusion, these
plants that are valuable genetic and breeding materials contain completely homozygous and
essentially intact genomes
Comprehensive study of the CuF<inf>2</inf> conversion reaction mechanism in a lithium ion battery
Conversion materials for lithium ion batteries have recently attracted considerable attention due to their exceptional specific capacities. Some metal fluorides, such as CuF2, are promising candidates for cathode materials owing to their high operating potential, which stems from the high electronegativity of fluorine. However, the high ionicity of the metal–fluorine bond leads to a large band gap that renders these materials poor electronic conductors. Nanosizing the active material and embedding it within a conductive matrix such as carbon can greatly improve its electrochemical performance. In contrast to other fluorides, such as FeF2 and NiF2, good capacity retention has not, however, been achieved for CuF2. The reaction mechanisms that occur in the first and subsequent cycles and the reasons for the poor charge performance of CuF2 are studied in this paper via a variety of characterization methods. In situ pair distribution function analysis clearly shows CuF2 conversion in the first discharge. However, few structural changes are seen in the following charge and subsequent cycles. Cyclic voltammetry results, in combination with in situ X-ray absorption near edge structure and ex situ nuclear magnetic resonance spectroscopy, indicate that Cu dissolution is associated with the consumption of the LiF phase, which occurs during the first charge via the formation of a Cu1+ intermediate. The dissolution process consequently prevents Cu and LiF from transforming back to CuF2. Such side reactions result in negligible capacity in subsequent cycles and make this material challenging to use in a rechargeable battery.We acknowledge the funding from the U.S. DOE BES via
funding to the EFRC NECCES, an Energy Frontier Research
Center funded by the U.S. Department of Energy, Office of
Science, Office of Basic Energy Sciences under Award Number
DE-SC0001294 (support for Rosa Robert and Lin-Shu Du)
and EPSRC via the “nanoionics” programme grant (support for
Xiao Hua). Use of the National Synchrotron Light Source
(NSLS), Brookhaven National Laboratory (BNL), was
supported by the U.S. Department of Energy, Office of
Science, Office of Basic Energy Sciences, under Contract No.
DE-AC02-98CH10886. Use of the Advanced Photon Source,
an Office of Science User Facility operated for the U.S.
Department of Energy (DOE) Office of Science by Argonne
National Laboratory, was supported by the U.S. DOE under
Contract No. DE-AC02-06CH11357.This is the final published version of the article. It first appeared at http://pubs.acs.org/doi/abs/10.1021/jp503902z and is posted here under the terms of ACS's Editors' Choice scheme (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html)
LRR-RLK family from two Citrus species: Genome-wide identification and evolutionary aspects
Background: Leucine-rich repeat receptor-like kinases (LRR-RLKs) represent the largest subfamily of plant RLKs. The functions of most LRR-RLKs have remained undiscovered, and a few that have been experimentally characterized have been shown to have important roles in growth and development as well as in defense responses. Although RLK subfamilies have been previously studied in many plants, no comprehensive study has been performed on this gene family in Citrus species, which have high economic importance and are frequent targets for emerging pathogens. In this study, we performed in silico analysis to identify and classify LRR-RLK homologues in the predicted proteomes of Citrus clementina (clementine) and Citrus sinensis (sweet orange). In addition, we used large-scale phylogenetic approaches to elucidate the evolutionary relationships of the LRR-RLKs and further narrowed the analysis to the LRR-XII group, which contains several previously described cell surface immune receptors. Results: We built integrative protein signature databases for Citrus clementina and Citrus sinensis using all predicted protein sequences obtained from whole genomes. A total of 300 and 297 proteins were identified as LRR-RLKs in C. clementina and C. sinensis, respectively. Maximum-likelihood phylogenetic trees were estimated using Arabidopsis LRR-RLK as a template and they allowed us to classify Citrus LRR- 34 RLKs into 16 groups. The LRR-XII group showed a remarkable expansion, containing approximately 150 paralogs encoded in each Citrus genome. Phylogenetic analysis also demonstrated the existence of two distinct LRR-XII clades, each one constituted mainly by RD and non-RD kinases. We identified 68 orthologous pairs from the C. clementina and C. sinensis LRR-XII genes. In addition, among the paralogs, we identified a subset of 78 and 62 clustered genes probably derived from tandem duplication events in the genomes of C. clementina and C. sinensis, respectively. Conclusions: This work provided the first comprehensive evolutionary analysis of the LRR-RLKs in Citrus. A large expansion of LRR-XII in Citrus genomes suggests that it might play a key role in adaptive responses in host-pathogen co-evolution, related to the perennial life cycle and domestication of the citrus crop species
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