Biology subjects

Sanchez-Segura, L.

Publications and source records attributed to Sanchez-Segura, L..

3 recordsLinked to original sources

bioRxiv2025

Host-Specific Transcriptional Responses of Phytophthora capsici During Early Crown Infection in Cucurbitaceous and Solanaceous Plants

Phytophthora capsici is a destructive, broad-host-range oomycete responsible for substantial losses in global agriculture. While most transcriptomic studies have focused on host responses, the mechanisms by which generalist pathogens dynamically adapt their infection programs to diverse plant species remain poorly understood. Here, we present a comparative transcriptomic analysis of P. capsici during early-stage crown infection in four taxonomically and immunologically distinct hosts, Cucumis sativus, Cucumis melo, Capsicum annuum (CM334), and Solanum lycopersicum, via RNA-seq and multiphoton microscopy. Focusing on crown infections, the natural entry point for the pathogen, we reveal host-specific transcriptional programs that underpin differential infection strategies and outcomes. Our data show that P. capsici exhibits tightly regulated, host-dependent deployment of key virulence factors, including RxLR, NLP, and CRN, and elicitin effectors and reprograms its metabolism to exploit host-specific nutritional environments. In rapidly necrotizing hosts such as tomato, the pathogen induces glycolytic and fatty acid pathways while repressing immunogenic effectors. In contrast, cucurbits support prolonged biotrophic colonization, accompanied by the upregulation of carbohydrate metabolism and membrane transport genes. In the partially resistant chili pepper CM334, P. capsici shows signs of metabolic stress, cell wall remodeling, and effector repression, which is consistent with failed invasion. Functional validation via RNAi-mediated silencing of selected effectors revealed distinct roles in modulating virulence and host necrosis, confirming the functional relevance of the transcriptomic profiles. Co-expression network analysis uncovered discrete transcriptional modules associated with tissue-specific colonization, nutrient acquisition, and immune evasion. These results reveal how a generalist soil-borne pathogen finely tunes its gene expression in response to host-specific constraints, revealing conserved and host-specific transcriptional strategies that drive infection success or failure. This work provides mechanistic insight into adaptive virulence and expands our understanding of host-pathogen compatibility in eukaryotic microbes.

molecular biology↗

bioRxiv2023

Macrophage-targeted DNA methyltransferase inhibitor SGI-1027 decreases atherosclerosis in ApoE-null mice

Background and aimsCorrection of vascular DNA hypermethylation may slow atherogenesis. We tested the anti-inflammatory and anti-atherogenic activity of macrophage-targeted DNA methyltransferase (DNMT) inhibitor SGI-1027. Methods, ResultsSGI-1027 was encapsulated into human serum albumin (HSA) nanoparticles (HSANP) functionalized with the PP1 peptide, a macrophage scavenger receptor 1 ligand, fused to a FLAG epitope (S-HSANP-FLAGPP1). Nanoparticle physico-chemical characteristics predicted good marginalization towards the vascular wall, although SGI-1027 encapsulation efficiency was relatively low ([~]23%). S-HSANP-FLAGPP1 were rapidly internalized compared to non-functionalized and, surprisingly, functionalized void controls, and induced a shift towards an anti-inflammatory profile of secreted cytokines in human THP-1 macrophages. S-HSANP-FLAGPP1 colonized the atheroma and induced a significant [~]44% reduction of atherosclerosis burden in the aortic tree of ApoE-null mice compared to controls. A reduction in aortic root atherosclerosis was observed, although primarily induced by HSANP irrespective of loading or functionalization. No alteration of body weight, non-vascular tissue gross histology, plasma glucose, triglyceride or cholesterol were observed. HSA whether free or structured in nanoparticles, induced a 3-4-fold increase in HDL compared to vehicle. ConclusionsWe confirm that DNMT inhibition is anti-atherogenic and provide proof of principle that targeted HSANP are effective carriers for those molecules. SGI-1027 displayed a novel anti-inflammatory activity that is independent of cell proliferation and therefore likely unrelated to DNMT inhibition. HDL elevation may represent an additional advantage of HSA-based nanocarriers.

pathology↗

bioRxiv2019

Antifungal activity of silver nanoparticles during in-vitro culture of Stevia rebaudiana Bertoni

Contamination by fungi and bacteria during the in-vitro propagation of plants leads to considerable losses of biological material and precludes phytosanitary certification. The anti-microbial effect of silver nanoparticles (AgNPs) may be an alternative for the eradication of in-vitro contaminants. This study evaluated the microbicidal activity of AgNPs on a recurrent fungus during the micropropagation of stevia (Stevia rebaudiana Bertoni). First, the fungus was isolated and identified at a molecular level by the sequencing and analysis of the ITS4/ITS5 rDNA region. The results of the phylogenetic analysis of various fungi species showed that the strain under study (16-166-H) belongs to the genus Sordaria and is 86.74% similar to S. tomento-alba (strain CBS 260.78). Subsequently, the inhibition of the growth of S. tomento-alba was tested under different concentrations of AgNPs (0, 25, 50, 100, and 200 mg L-1), observing that 50 and 100 mg L-1 achieve ca. 50% growth inhibition (IC50), while 200 mg L-1 produces a drastic inhibition. On the other hand, the shape and size of AgNPs was examined using transmission electron microscopy (TEM), and the transport and accumulation of AgNPs in S. tomento-alba cells were monitored through multiphoton microscopy. The morphological and fluorescence analyses showed that AgNPs display different sizes, with larger nanoparticles retained in fungal cell walls while smaller AgNPs penetrate into fungal cells. Probably, apoplastic and symplastic mechanisms involved in the accumulation and transport of AgNPs affect the metabolic processes of the fungus, thus inhibiting its growth. These results suggest that AgNPs possess antifungal activity and can be used in the eradication of contaminants during the in-vitro culture of plant species.

microbiology↗