Entries by Matthias Benoit

An epigenetic origin behind the transgenerational fitness decline in chromatin assembly impaired plants (New Phytol) ($)

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Packaging of nuclear DNA in chromatin is critical for the maintenance of genome integrity as well as fundamental cellular processes such as DNA replication and transcription. Chromatin assembly is mediated by histone chaperones, such as Chromatin Assembly Factor 1 (CAF-1). CAF-1 ensures faithful replication-coupled chromatin assembly. Arabidopsis plants lacking a functional CAF-1 show molecular and […]

Initiation of meiotic recombination is regulated by epigenetic marks and chromatin structure (Genome Res.)

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Meiotic recombination is an important source of genetic diversity by allowing the reshuffling of parental alleles during meiosis. It requires the generation of DNA double-strand breaks (DSBs) initiated by the activity of the SPO11 protein complex. In plants, the impact of chromatin structure and DNA methylation on the meiotic DSB landscape genome-wide remains unclear. In […]

Maize adaptation to higher latitudes has been facilitated by transposon activities.

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Proc. Natl. Acad. Sci. USA. Flowering is a major determinant of crop adaptation to new environments. Starting from its tropical origins and requirement for short-day conditions to flower, natural selection and breeding have allowed maize to adapt to long-day environments and thus be grown over a wider range of latitudes, from Canada to Chile. Nevertheless, […]

Evolution of transposon-encoded anti-silencing factors in Arabidopsis ($)

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Transposable elements (TEs) are a major component of eukaryotic genomes. Their activity is silenced by epigenetic mechanisms such as chromatin modifications and DNA methylation in order to avoid deleterious effects on host genome stability. Nevertheless, how TEs overcome silencing by the host and propagate is poorly understood. In this study, the authors describe the activity […]

Methylome robustness in plants is conferred by a methylation-sensitive system.

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DNA methylation is instrumental in promoting transcriptional silencing at repetitive elements, inhibiting illegitimate recombination and establishing genomic imprinting. In plants, DNA methylation profiles are stably inherited over generations through the activities of cytosine DNA methyltransferases and 5-methylcytosine glycosylases. Nevertheless, how they interact and influence each other’s activities is not well understood. In this study, Williams […]

Trees are particularly robust to fixed somatic mutations

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Plants lack a developmentally defined germline and gametes originate only late during plant development. This allows mutations acquired during the vegetative growth (somatic mutations) to be transmitted to the reproductive organs. The accumulation of mutations is relatively low in annual plants such as Arabidopsis, in which the fixed mutation rate is estimated at approximately one […]

Whole-genome sequencing reveals the extent of GC-biased gene conversion in plants and fungi ($)

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Gene conversion, a mechanism involving the unidirectional exchange of DNA from a donor to an acceptor sequence through homologous recombination, is a major driver of genome evolution. It has been speculated that gene conversion may be biased towards GC alleles, and thus favours accumulation of GC in the genome. Nevertheless, this hypothesis has never been […]

Regulatory small RNAs responsible for natural variation in snapdragon flower color patterning ($)

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Flower color pattern is a major trait influencing pollinator attraction, but underlying regulatory mechanisms are still poorly understood. Using co-existing Snapdragon subspecies displaying different flower pigmentation motifs, Bradley et al. investigated the molecular basis of flower color patterning. They identified an inverted gene duplication producing small RNAs targeting a gene involved in the biosynthesis of […]

Amplification of plant disease-resistance genes in pepper is intimately linked to transposon activity

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Peppers are an economically and ecologically important crop plants, but genomic resources are rather scarce. The authors provide here new reference genome sequences for three species of hot pepper (Capsicum baccatum, C. chinense and C. annuum), identifying evolutionary forces that have shaped pepper genomes. Based on these new resources, the study reveals important species-specific chromosomal […]