Biology subjects

Charif, D.

Publications and source records attributed to Charif, D..

4 recordsLinked to original sources

bioRxiv2024

FIGL1 limits the formation of meiotic non crossover events in Arabidopsis thaliana

Meiotic recombination produces both crossover and non crossover events that are essential in the history of population genetics and evolution of species. In Arabidopsis thaliana, several pathways control the rate and distribution of crossovers. Here, by sequencing the four products of a series of tetrads, we confirm the antiCO role of RECQ4A, RECQ4B, FIGL1 and FANCM. Moreover, when one of this gene is mutated, complex chimeric gene conversion events associated to crossover are observed suggesting a role of these proteins in limiting the multiple strand invasions. Nothing was known about the factors that could limit or increase NCOs. Here, we show that FIGL1 plays a major role in controlling the NCO number.

genetics↗

bioRxiv2024

The unusual orf117Sha locus causes desynchronization of pollen development in the Arabidopsis gametophytic Sha CMS

Cytoplasmic male sterility (CMS) is of major agronomical relevance in hybrid breeding. In gametophytic CMS, abortion of pollen is determined by the grain genotype, while in sporophytic CMS, it is determined by the mother plant genotype. While several CMS mechanisms have been dissected at the molecular level, gametophytic CMS has not been straightforwardly accessible. We used the gametophytic Sha-CMS in Arabidopsis to characterize the cause and process of pollen abortion by implementing in vivo biosensing in single pollen and mitoTALEN mutagenesis. We obtained conclusive evidence that orf117Sha is the CMS-causing gene, despite distinct characteristics from other CMS-genes. We measured the in vivo cytosolic ATP content in single pollen, followed pollen development and analyzed pollen mitochondrial volume in two genotypes that differed only by the presence of the orf117Sha locus. Our results show that the Sha-CMS is not triggered by ATP deficiency. Instead, we observed desynchronization of a pollen developmental program. Pollen death occurred independently in pollen grains at diverse stages and was preceded by mitochondrial swelling. We conclude that pollen death is grain-autonomous in Sha-CMS and propose that mitochondrial permeability transition, which was previously described as a hallmark of developmental and environmental-triggered cell death programs, precedes pollen death in Sha-CMS. HighlightThe Arabidopsis CMS-causing gene orf117Sha does not limit pollen ATP supply. Pollen-centered approaches show desynchronization of development and mitochondrial swelling before pollen death, which occurred at diverse stages.

plant biology↗

bioRxiv2023

Rapid meiotic prophase chromosome movements in Arabidopsis thaliana are linked to essential reorganization at the nuclear envelope

Meiotic rapid prophase chromosome movements (RPMs) require connections between the chromosomes and the cytoskeleton, involving SUN (Sad1/UNC-84)-domain-containing proteins at the inner nuclear envelope (NE). RPMs remain significantly understudied in plants, notably with respect to their importance in the regulation of meiosis. Here, we demonstrate that Arabidopsis thaliana meiotic centromeres undergo rapid (up to 500 nm/s) and uncoordinated movements during the zygotene and pachytene stages. RPMs are not affected by altered chromosome organization and recombination but are abolished in the double mutant sun1 sun2. We also document the changes in chromosome dynamics and nucleus organization during the transition from leptotene to zygotene, including telomere attachment to SUN-enriched NE domains, bouquet formation, and nucleolus displacement, all of which were defective in sun1 sun2. These results establish A. thaliana as a new model species for studying the functional implications of meiotic RPMs and demonstrate the mechanistic conservation of telomere-led RPMs in plants.

genetics↗

bioRxiv2023

A transcriptomic dataset for investigating the Arabidopsis Unfolded Protein Response under chronic, proteotoxic endoplasmic reticulum stress

The Unfolded Protein Response (UPR) is a retrograde, ER-to-nucleus, signalling pathway which is conserved across kingdoms. In plants, it contributes to development, reproduction, immunity and tolerance to abiotic stress. This RNA sequencing dataset was produced from 14-day-old Arabidopsis thaliana seedlings challenged by tunicamycin (Tm), an antibiotic inhibiting Asn-linked glycosylation in the endoplasmic reticulum (ER), causing an ER stress and eventually activating the UPR. Wild-type (WT) and a double mutant deficient for two main actors of the UPR (INOSITOL-REQUIRING ENZYME 1A and INOSITOL-REQUIRING ENZYME 1B) were used as genetic backgrounds in our experimental setup, allowing to distinguish among differentially-expressed genes (DEGs) which ones are dependent on or independent on IRE1s. Also, shoots and roots were harvested separately to determine organ-specific transcriptomic responses to Tm. Library and sequencing were performed using DNBseq technology by the Beijing Genomics Institute. Reads were mapped and quantified against the Arabidopsis genome. Differentially-expressed genes were identified using Rflomics upon filtering and normalization by the Trimmed Mean of M-value (TMM) method. While the genotype effect was weak under mock conditions (with a total of 182 DEGs in shoots and 195 DEGs in roots), the tunicamycin effect on each genotype was characterized by several hundred of DEGs in both shoots and roots. Among these genes, 872 and 563 genes were statistically up- and down-regulated in the shoot tissues of the double mutant when compared to those of WT, respectively. In roots of Tm-challenged seedlings, 425 and 439 genes were significantly up- and down-regulated in mutants with respect to WT. We believe that our dataset could be reused for investigating any biological questions linked to ER homeostasis and its role in plant physiology. SPECIFICATIONS TABLE O_TBL View this table: org.highwire.dtl.DTLVardef@a6de12org.highwire.dtl.DTLVardef@13d7c62org.highwire.dtl.DTLVardef@1b14109org.highwire.dtl.DTLVardef@24dbaborg.highwire.dtl.DTLVardef@1d1c1e1_HPS_FORMAT_FIGEXP M_TBL C_TBL

plant biology↗