Gonzalez-Garcia, M. | Search bioRxiv

bioRxiv2025

Arabidopsis ecotype screening reveals novel sources of clubroot resistance and insights into resistance inheritance

Clubroot, caused by Plasmodiophora brassicae, poses a persistent threat to Brassicaceae crops, particularly in regions where resistant cultivars are under strong selection pressure. To identify new sources of resistance and better understand the underlying genetic mechanisms, we evaluated 60 Arabidopsis thaliana ecotypes against the highly virulent Canadian pathotype 3A. Using stringent phenotyping criteria, pathogen DNA quantification, and survival analysis, we identified eight resistant ecotypes, including two novel sources, Marce-1 and DraII-6. DraII-6 exhibited exceptionally low disease symptoms and a high survival rate. While the resistance gene RPB1/WeiTsing was present in most ecotypes, its expression in DraII-6 was significantly elevated at early infection stages, suggesting a potential role in pathogen suppression. However, genetic analysis of F1 and F2 progeny from a DraII-6 x Col-0 cross revealed a recessive resistance pattern, supporting the hypothesis that RPB1 alone may not be sufficient to confer resistance to clubroot in DraII-6. Our findings highlight the complexity of clubroot resistance and the need for further research into gene regulation and resistance networks beyond RPB1, particularly in the context of translating Arabidopsis-based insights to Brassica crops. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC="FIGDIR/small/649024v1_ufig1.gif" ALT="Figure 1"> View larger version (98K): org.highwire.dtl.DTLVardef@1e30ef3org.highwire.dtl.DTLVardef@1ea7aa4org.highwire.dtl.DTLVardef@119c0a3org.highwire.dtl.DTLVardef@1b62891_HPS_FORMAT_FIGEXP M_FIG C_FIG Natural variability of Arabidopsis thaliana ecotypes in response to the Canadian clubroot pathotype 3A. The abstract also celebrates the first author, Melaine Gonzalez-Garcia, who is submitting this manuscript just one week before welcoming her first child.

plant biology↗

bioRxiv2023

Design of a stem cell-based therapy for ependymal repair in hydrocephalus associated with germinal matrix hemorrhages

Germinal matrix hemorrhages (GMH) and the consequent posthemorrhagic hydrocephalus (PHH) are among the most common and severe neurological complications of preterm birth that require lifelong complex neurosurgical care. GMH and PHH provoke disruption of neuroepithelium/ependyma development, a key structure implicated in brain development and homeostasis. Neuroepithelial/ependymal damage causes lifelong cognitive and motor deficits; however, no therapy is directed to recover the damaged ependyma. This study is aimed to test the possibilities of ependymal repair in GMH/PHH using neural stem cells (NSCs) or ependymal progenitors (EpPs). Thus, it sets the basis for a therapeutic approach to treating ependymal damage and preventing brain developmental deficits. GMH/PHH was induced in 4-day-old mice using different experimental procedures involving collagenase, blood, or blood serum injections. PHH severity was characterized using magnetic resonance, immunofluorescence, and protein expression quantification with mass spectrometry. Additionally, a new exvivo approach using ventricular walls from mice developing moderate and severe GMH/PHH was generated to study ependymal restoration and wall regeneration after stem cell treatments. NSCs or EpPs obtained from newborn mice were transplanted in the explants, and pretreatment with mesenchymal stem cells (MSCs) was tested. Ependymal differentiation and the effect of MSC-conditioned microenvironment were investigated in both explants and primary cultures. In the animals, PHH severity was correlated with the extension of GMH, ependymal disruption, astroglial/microglial reactions, and ventriculomegaly. In the explants, the severity and extension of GMH hindered the survival rates of the transplanted NSCs/EpPs. In the explants affected with GMH, new multiciliated ependymal cells could be generated from transplanted NSCs and, more efficiently, from EpPs. Blood and TNF negatively affected ciliogenesis in cells expressing Foxj1. Pretreatment with mesenchymal stem cells (MSC) improved the survival rates of EpPs and ependymal differentiation while reducing the edematous and inflammatory conditions in the explants. In conclusion, in GMH/PHH, the ependyma can be restored from either NSC or EpP transplantation, being EpPs in an MSC-conditioned microenvironment more efficient for this purpose. Modifying the neuroinflammatory microenvironment by MSC pretreatment positively influenced the success of the ependymal restoration.

neuroscience↗