ORCID Profile
0000-0003-0842-9808
Current Organisations
Northumbria University
,
CNRS Délégation Alpes
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Publisher: Cold Spring Harbor Laboratory
Date: 09-10-2019
DOI: 10.1101/799338
Abstract: Seeds are complex biological systems comprising three genetically distinct tissues nested one inside another (embryo, endosperm and maternal tissues). However, the complexity of the kernel makes it difficult to understand inter compartment interactions without access to spatially accurate information. Here we took advantage of the large size of the maize kernel to characterize genome-wide expression profiles of tissues at embryo/endosperm interfaces. Our analysis identifies specific transcriptomic signatures in two interface tissues compared to whole seed compartments: The scutellar aleurone layer (SAL), and the newly named endosperm adjacent to scutellum (EAS). The EAS, which appears around 9 days after pollination and persists for around 11 days, is confined to one to three endosperm cell layers adjacent to the embryonic scutellum. Its transcriptome is enriched in genes encoding transporters. The absence of the embryo in an embryo specific ( emb ) mutant can alter the expression pattern of EAS marker genes. The detection of cell death in some EAS cells together with an accumulation of crushed cell walls suggests that the EAS is a dynamic zone from which cell layers in contact with the embryo are regularly eliminated, and to which additional endosperm cells are recruited as the embryo grows.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-08-2014
Abstract: Many domesticated plants arose through the meeting of multiple genomes through hybridization and genome doubling, known as polyploidy. Chalhoub et al. sequenced the polyploid genome of Brassica napus , which originated from a recent combination of two distinct genomes approximately 7500 years ago and gave rise to the crops of rape oilseed (canola), kale, and rutabaga. B. napus has undergone multiple events affecting differently sized genetic regions where a gene from one progenitor species has been converted to the copy from a second progenitor species. Some of these gene conversion events appear to have been selected by humans as part of the process of domestication and crop improvement. Science , this issue p. 950
Publisher: Springer Science and Business Media LLC
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 28-08-2011
DOI: 10.1038/NG.919
Abstract: We report the annotation and analysis of the draft genome sequence of Brassica rapa accession Chiifu-401-42, a Chinese cabbage. We modeled 41,174 protein coding genes in the B. rapa genome, which has undergone genome triplication. We used Arabidopsis thaliana as an outgroup for investigating the consequences of genome triplication, such as structural and functional evolution. The extent of gene loss (fractionation) among triplicated genome segments varies, with one of the three copies consistently retaining a disproportionately large fraction of the genes expected to have been present in its ancestor. Variation in the number of members of gene families present in the genome may contribute to the remarkable morphological plasticity of Brassica species. The B. rapa genome sequence provides an important resource for studying the evolution of polyploid genomes and underpins the genetic improvement of Brassica oil and vegetable crops.
Publisher: Springer Science and Business Media LLC
Date: 25-01-2019
DOI: 10.1007/S00299-019-02378-1
Abstract: The analysis of 93 mutant alleles in 18 genes demonstrated that CRISPR-Cas9 is a robust tool for targeted mutagenesis in maize, permitting efficient generation of single and multiple knockouts. CRISPR-Cas9 technology is a simple and efficient tool for targeted mutagenesis of the genome. It has been implemented in many plant species, including crops such as maize. Here we report single- and multiple-gene mutagenesis via stably transformed maize plants. Two different CRISPR-Cas9 vectors were used allowing the expression of multiple guide RNAs and different strategies to knockout either independent or paralogous genes. A total of 12 plasmids, representing 28 different single guide RNAs (sgRNAs), were generated to target 20 genes. For 18 of these genes, at least one mutant allele was obtained, while two genes were recalcitrant to sequence editing. 19% (16/83) of mutant plants showed biallelic mutations. Small insertions or deletions of less than ten nucleotides were most frequently observed, regardless of whether the gene was targeted by one or more sgRNAs. Deletions of defined regions located between the target sites of two guide RNAs were also reported although the exact deletion size was variable. Double and triple mutants were created in a single step, which is especially valuable for functional analysis of genes with strong genetic linkage. Off-target effects were theoretically limited due to rigorous sgRNA design and random experimental checks at three potential off-target sites did not reveal any editing. Sanger chromatograms allowed to unambiguously class the primary transformants the majority (85%) were fully edited plants transmitting systematically all detected mutations to the next generation, generally following Mendelian segregation.
Publisher: Oxford University Press (OUP)
Date: 21-02-2020
DOI: 10.1105/TPC.19.00756
Publisher: Frontiers Media SA
Date: 26-04-2021
DOI: 10.3389/FPUBH.2021.646916
Abstract: This paper draws upon the concept of recreancy to examine the mental well-being of university students during the Covid-19 pandemic. Briefly, recreancy is loss of societal trust that results when institutional actors can no longer be counted on to perform their responsibilities. Our study of mental well-being and recreancy focuses on the role of universities and government regulators within the education sector. We surveyed 600 UK students attending 161 different public higher education providers in October 2020 during a time when many UK students were isolated in their residences and engaged in online learning. We assessed student well-being using the Short Warwick-Edinburgh Mental Well-being Scale (scored 7–35) and found the mean score to be 19.9 [95% confidence interval (CI) 19.6, 20.2]. This level of well-being indicates that a significant proportion of UK students face low levels of mental well-being. Structural equation modeling (SEM) analysis indicates that high recreancy—measured as a low trust in universities and the government—is associated with low levels of mental well-being across the student s le. While these findings are suggestive, they are also important and we suggest that government and university leaders should not only work to increase food and housing security during the Covid-19 pandemic, but also consider how to combat various sector trends that might intensify recreancy.
Publisher: Frontiers Media SA
Date: 28-11-2022
DOI: 10.3389/FPLS.2022.1010030
Abstract: Despite its rapid worldwide adoption as an efficient mutagenesis tool, plant genome editing remains a labor-intensive process requiring often several months of in vitro culture to obtain mutant plantlets. To avoid a waste in time and money and to test, in only a few days, the efficiency of molecular constructs or novel Cas9 variants (clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9) prior to stable transformation, rapid analysis tools are helpful. To this end, a streamlined maize protoplast system for transient expression of CRISPR/Cas9 tools coupled to NGS (next generation sequencing) analysis and a novel bioinformatics pipeline was established. Mutation types found with high frequency in maize leaf protoplasts had a trend to be the ones observed after stable transformation of immature maize embryos. The protoplast system also allowed to conclude that modifications of the sgRNA (single guide RNA) scaffold leave little room for improvement, that relaxed PAM (protospacer adjacent motif) sites increase the choice of target sites for genome editing, albeit with decreased frequency, and that efficient base editing in maize could be achieved for certain but not all target sites. Phenotypic analysis of base edited mutant maize plants demonstrated that the introduction of a stop codon but not the mutation of a serine predicted to be phosphorylated in the bHLH (basic helix loop helix) transcription factor ZmICEa (INDUCER OF CBF EXPRESSIONa) caused abnormal stomata, pale leaves and eventual plant death two months after sowing.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-09-2014
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: France
Location: France
No related grants have been discovered for Jérémy Just.