Biology subjects

Restrepo, S.

Publications and source records attributed to Restrepo, S..

4 recordsLinked to original sources

bioRxiv2025

Microscopical and molecular characterization of the infection cycle of Phytophthora betacei during disease development on tree tomato (Solanum betaceum).

Phytophthora betacei is a recently described oomycete plant pathogen closely related to Phytophthora infestans sensu stricto. This plant pathogen naturally infects tree tomato (Solanum betaceum) but has not been reported on tomatoes and potatoes, the primary hosts of P. infestans. The aim of this study was to characterize the infection cycle of P. betacei using microscopy and molecular approaches. Several strains were inoculated in susceptible tree tomato plants and disease progression was monitored via six epidemiological parameters. Although different P. betacei strains displayed a highly variable disease phenotype, the most aggressive one was chosen for further plant inoculations. Samples at different time points of the infection cycle were analyzed at the cellular level via light and scanning electron microscopy (SEM) and at the molecular level via qRT-PCR of infection-stage-specific markers. The infection cycle of P. betacei differed from that of P. infestans in having a longer biotrophic stage, larger lesions, and higher sporulation capacity. Additionally, P. betacei transcriptomic profiles were monitored along the infection cycle via RNAseq and evidenced a changing expression landscape that supports an elongated hemibiotrophic transition and a clear distinction from what is being expressed in the mycelium or the sporangia. This study provides novel insights into the interaction between P. betacei and S. betaceum.

plant biology↗

bioRxiv2021

Evaluation of small non-coding RNAs as a possible epigenetic mechanism mediating the transition from biotrophy to necrotrophy in the life cycle of Phytophthora infestans

Phytophthora infestans, causal agent of late blight disease of potatoes, causes billion-dollar losses worldwide each year. This plant pathogen is a hemibiotroph, first feeding on the host and later killing it. Even though the transcription dynamics of this transition are characterized, the role that small non-coding RNAs (sRNAs) might have is still unknown. Furthermore, a bioinformatic pipeline to search and analyze sRNAs in P. infestans, is needed. Using our proposed pipeline, 146 sRNAs were found to be significantly differentially expressed between the evaluated stages of the pathogens life cycle. One hundred of these sRNAs were successfully annotated and classified into nine functional categories. The expression of the genes associated to ten of these sRNAs was validated via qRT-PCR. Among these, the expression levels of genes encoding for effectors were inversely correlated to that of the sRNAs aligning to them, which is expected if sRNAs are indeed regulating their expression. This correlation was not clear for sRNAs in other functional categories and should not be confused with strict causality. This study works as a starting point for considering sRNAs as role players in the transition from biotrophy to necrotrophy in P. infestans when infecting Solanum tuberosum.

microbiology↗

bioRxiv2020

An integrative approach points to membrane composition as a key factor in E. coli persistence

Many diverse bacteria can enter non- or slow-growing states where they are transiently tolerant to antibiotics. Despite its medical importance, the genetic mechanisms underlying this persistence remain largely unknown, especially for spontaneous (type II) persistence that arise during exponential growth in rich medium. To address this challenge, here we combine genomic, transcriptomic and lipidomic analysis to identify the persistence mechanisms. We first analyzed the genome of the high-persistence mutant Escherichia coli DS1 (hipQ) to identify candidate genes for the high persistence phenotype. We then compared the gene expression profile of spontaneous persisters to normally growing cells with RNAseq and find that the activation of stress response mechanisms is likely not very important in the entrance into hipQ-driven spontaneous persistence. Transcriptomic results also suggest that modifications in the cell membrane play an important role, as further corroborated by lipidomic profiles showing a higher level of unsaturated fatty acids in spontaneous persisters compared to induced persisters or normally growing cells. Taken together, our results indicate that changing membrane composition is a key process in persistence, and further our understanding of spontaneous persister cells from the DS1 (hipQ) context.

microbiology↗

bioRxiv2016

Ecological speciation within the Phytophthora group

Over the past few years, symptoms akin to late blight disease have been reported on a variety of crop plants in South America. Despite the economic importance of these crops, the causal agents of the diseases belonging to the genus Phytophthora have not been completely characterized. In this study, we used an integrative approach that leveraged morphological, ecological, and genetic approaches to explore cryptic speciation within P. infestans sensu lato. We described a new Phytophthora species collected in Colombia from tree tomato (Solanum betaceum), a semi-domesticated fruit. All morphological traits and population genetic analyses, using microsatellite data and a reduced representation of single nucleotide polymorphism (SNP) data, support the description of the new species, Phytophthora betacei sp. nov. We have demonstrated that ecological differences are important in the persistence of P. infestans and P. betacei as genetically isolated units across an overlapping area in the northern Andes.

evolutionary biology↗