Biology subjects

Blanchard, C.

Publications and source records attributed to Blanchard, C..

5 recordsLinked to original sources

bioRxiv2026

The segregase CDC48 integrates blue light and hormonal cues to regulate photomorphogenesis in Arabidopsis

Photomorphogenesis allows plants to adjust growth to ambient light conditions and relies on protein quality control to ensure the timely turnover of signaling components. The conserved AAA+ ATPase CDC48, along with its cofactors NPL4 and UFD1, is a crucial regulator of proteasomal degradation. While well characterized in other organisms, its role in plant development remains largely unexplored. Here, we show that CDC48 is required for blue light-mediated photomorphogenesis in Arabidopsis. Under blue light, CDC48A accumulates at the plasma membrane and in the nucleus, and cdc48a mutants fail to repress hypocotyl elongation properly. Similar phenotypes are observed upon inhibition of CDC48 or in npl4 and ufd1 mutants. Genetic and biochemical analyses further reveal that CDC48A negatively regulates gibberellin (GA) signaling. Consistently, UFD1 directly interacts with the GA receptor GID1 to promote its degradation. Together, these findings demonstrate that CDC48A integrates light and hormonal cues through protein homeostasis to regulate photomorphogenic development.

plant biology↗

bioRxiv2025

The unfolded protein response in grapevine: abiotic and biotic stresses induce the expression of VvbZIP60, VvbZIP17, VvBIP3, and VvIRE1

A wide range of stresses can lead to the accumulation of unfolded or misfolded proteins in the lumen of the endoplasmic reticulum (ER), a condition known as ER stress. To restore proteostasis, eukaryotic cells activate a signaling network called the unfolded protein response (UPR). In Vitis vinifera, two arms of the UPR have been identified: the IRE1/bZIP60 arm and the bZIP17 arm. Notably, no putative ortholog of bZIP28 has been found in V. vinifera, whereas this is the case for Brassicaceae species. We demonstrated that VvbZIP60 undergoes unconventional splicing upon treatment with dithiothreitol (DTT) and tunicamycin (TM), both classical ER stress inducers. Moreover, after testing several abiotic factors, we observed a strong transcriptional activation of UPR-related genes in response to heat and osmotic stresses, as well as copper exposure. Grapevine is also subject to a broad range of microbial challenges, including pathogens such as Plasmopara viticola and Botrytis cinerea. Both pathogens triggered UPR genes activation in grapevine leaves and berries. Interestingly, VvbZIP17 was also upregulated in green berries, a developmental stage associated with strong basal resistance to B. cinerea. Collectively, these findings suggest that the IRE1/bZIP60 and bZIP17 arms of the UPR are not only structurally conserved in grapevine but are also transcriptionally responsive to a variety of abiotic and biotic stresses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/669611v2_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@13e0b15org.highwire.dtl.DTLVardef@49967dorg.highwire.dtl.DTLVardef@1371bfborg.highwire.dtl.DTLVardef@10e09b2_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2025

Evolutionary responses to historic drought across the range of scarlet monkeyflower

Adaptive evolution is a key means for populations to persist under environmental change, yet whether populations across a species range can adapt quickly enough to keep pace with climate change remains unknown. The breeders equation predicts the evolutionary change in a trait from one generation to the next as the product of the selection differential and the narrow-sense heritability in that trait. Incorporating these aspects of the breeders equation, we performed a resurrection study with the scarlet monkeyflower (Mimulus cardinalis) to evaluate whether traits associated with drought adaptation have evolved in populations across a species range in response to extreme drought. We compared trait and fitness differences of pre-drought ancestors and post-drought descendants from six populations transplanted into three latitudinally-arrayed common gardens and quantified phenotypic selection and trait heritabilities. The strength, direction, and mode of selection varied among traits and gardens. Trait heritabilities were relatively low, and did not differ dramatically among populations or gardens. Overall, instances of evolutionary responses between ancestors and descendants were few and small in magnitude, but the magnitude of these evolutionary differences varied among gardens. Together, these results suggest that the expression of genetic variation, and thus traits, depend on the environment, and that environmental variability in field settings may mask the genetic variation that is often detected in greenhouse environments.

evolutionary biology↗

bioRxiv2025

In utero lipid nanoparticle delivery achieves robust editing in hematopoietic stem cells.

Efficient delivery of genome editing reagents to hematopoietic stem cells (HSCs) has limited the development of in vivo gene editing therapies for hematologic disease. Here, we exploit developmental hematopoiesis to enable HSC targeting using clinically scalable lipid nanoparticles (LNPs). During fetal development, HSCs reside in the liver, a tissue that is efficiently accessed by LNPs. We show that in utero delivery of LNPs carrying Cre recombinase or CRISPR-Cas9 components results in transfection and genome editing of bona fide long-term repopulating HSCs. Edited HSCs maintain multilineage reconstitution capacity following transplantation, demonstrating preserved stem cell function. Comparative studies reveal that both fetal and early neonatal delivery permit HSC editing, with greater efficiency during fetal liver hematopoiesis. We further identify an LNP formulation that enhance HSC targeting and enable robust neonatal HSC editing without antibody-mediated targeting. Finally, combined delivery of Cas9 via LNPs and a repair template via adeno-associated virus in neonatal mice enables in vivo homology-directed repair in multiple tissues. Together, these findings establish the perinatal period as a therapeutic window for in vivo HSC genome editing and provide a scalable strategy for treating severe early-onset hematologic diseases.

cell biology↗

bioRxiv2023

UPR pathway is required for Arabidopsis thaliana resistance to necrophic fungal pathogens.

The Unfolded Protein Response (UPR) is a retrograde signalling pathway which is activated when endoplasmic reticulum (ER) proteostasis is disturbed. Here, we have investigated by reverse genetics the contribution of such pathway in Arabidopsis thaliana response to two necrotrophic fungi of agricultural importance, Botrytis cinere a which is responsible for the development of grey mold disease, and Alternaria brassicicola which triggers black spot disease. We found that the branch of UPR dependent on the INOSITOL-REQUIRING ENZYME 1 (IRE1) and the transcription factor (TF) bZIP60 is required to restrict foliar necrotic symptoms induced by both fungi. Accordingly, focussing on B. cinerea, we provided evidence for the production of the active bZIP60 form during infection. This activation was accompanied by an increased expression of UPR-responsive genes coding for ER-localized chaperones and co-chaperones that belong to the ER-Quality Control (ER-QC) system. Furthermore, mutants deficient for two ER-QC components were also more susceptible to infection. By contrast, investigating the involvement of CELL DIVISION CYCLE 48 (CDC48) AAA+-ATPAses that assist ER-Associated Degradation (ERAD) pathway for disposal of luminal unfolded proteins, we showed that a series of mutants and transgenics are more resistant to grey mold disease. Seeking for molecular insights into how the ER could shape Arabidopsis immune response to B. cinerea, we quantified the expression of defence gene and cell death markers in single bzip60 and double ire1 mutants. However, none of those genes were mis-regulated in mutant genetic backgrounds, indicating that IRE1-bZIP60 branch of UPR modulates the Arabidopsis response to B. cinerea by a yet-to-be-identified mechanism. Interestingly, we identified the NAC053/NTL4 TF as a potential actor of this unknown mechanism, linking the UPR and proteasome stress regulon. Author summaryNecrotrophic fungi are one of the most economically significant plant pathogens worldwide, inflicting massive pre- and post-harvest losses on a wide range of fruit and vegetable crops. They adopt a necrotrophic lifestyle, deriving their nutrients predominantly from dead plant tissues to complete their life cycle. Botrytis cinerea is the causal agent of grey mold and no plant shows complete resistance towards this pathogen. The use of genetic models such as the plant Arabidopsis thaliana has partially enabled the understanding of the immunity mechanisms involved in the plants response to B. cinerea. Our work provides new insights into the cellular mechanisms of how plants cope with this pathogen. In this context, by means of a reverse genetic approach, we explored the role of the Unfolded Protein Response (UPR), a cell signalling pathway regulating protein homeostasis within the endoplasmic reticulum (ER) and thus protecting cells from a harmful over-accumulation of aberrant or misfolded proteins.

plant biology↗