EBP-Colombia and the bioeconomy: Genomics in the service of biodiversity conservation and sustainable development.

The 2016 Peace Agreement has increased access to Colombia's unique ecosystems, which remain understudied and increasingly under threat. The Colombian government has recently announced its National Bioeconomic Strategy (NBS), founded on the sustainable characterization, management, and conservation of the nation's biodiversity as a means to achieve sustainability and peace. Molecular tools will accelerate such endeavors, but capacity remains limited in Colombia. The Earth Biogenome Project's (EBP) objective is to characterize the genomes of all eukaryotic life on Earth through networks of partner institutions focused on sequencing either specific taxa or eukaryotic communities at regional or national scales. Colombia's immense biodiversity and emerging network of stakeholders have inspired the creation of the national partnership "EBP-Colombia." Here, we discuss how this Colombian-driven collaboration between government, academia, and the private sector is integrating research with sustainable, environmentally focused strategies to develop Colombia's postconflict bioeconomy and conserve biological and cultural diversity. EBP-Colombia will accelerate the uptake of technology and promote partnership and exchange of knowledge among Colombian stakeholders and the EBP's global network of experts; assist with conservation strategies to preserve Colombia's vast biological wealth; and promote innovative approaches among public and private institutions in sectors such as agriculture, tourism, recycling, and medicine. EBP-Colombia can thus support Colombia's NBS with the objective of sustainable and inclusive development to address the many social, environmental, and economic challenges, including conflict, inequality, poverty, and low agricultural productivity, and so, offer an alternative model for economic development that similarly placed countries can adopt.

Reconstructing the Global Migration History of Phytophthora infestans Toward Colombia.

The evolution of new variants of plant pathogens is one of the biggest challenges to controlling and managing plant diseases. Of the forces driving these evolutionary processes, global migration events are particularly important for widely distributed diseases such as potato late blight, caused by the oomycete Phytophthora infestans. However, little is known about its migration routes outside North America and Europe. This work used genotypic data from population studies to elucidate the migration history originating the Colombian P. infestans population. For this purpose, a dataset of 1,706 P. infestans genotypes was recollected, representing North and South America, Europe, and Asia. Descriptive analysis and historical records from North America and Europe were used to propose three global migration hypotheses, differing on the origin of the disease (Mexico or Peru) and the hypothesis that it returned to South America from Europe. These scenarios were tested using approximate Bayesian computation. According to this analysis, the most probable scenario (posterior probability = 0.631) was the one proposing a Peruvian origin for P. infestans, an initial migration toward Colombia and Mexico, and a later event from Mexico to the United States and then to Europe and Asia, with no return to northern South America. In Colombia, the scenario considering a single migration from Peru and posterior migrations within Colombia was the most probable, with a posterior probability of 0.640. The obtained results support the hypothesis of a Peruvian origin for P. infestans followed by rare colonization events worldwide.

Genomes of four Streptomyces strains reveal insights into putative new species and pathogenicity of scab-causing organisms.

Genomes of four Streptomyces isolates, two putative new species (Streptomyces sp. JH14 and Streptomyces sp. JH34) and two non thaxtomin-producing pathogens (Streptomyces sp. JH002 and Streptomyces sp. JH010) isolated from potato fields in Colombia were selected to investigate their taxonomic classification, their pathogenicity, and the production of unique secondary metabolites of Streptomycetes inhabiting potato crops in this region. The average nucleotide identity (ANI) value calculated between Streptomyces sp. JH34 and its closest relatives (92.23%) classified this isolate as a new species. However, Streptomyces sp. JH14 could not be classified as a new species due to the lack of genomic data of closely related strains. Phylogenetic analysis based on 231 single-copy core genes, confirmed that the two pathogenic isolates (Streptomyces sp. JH010 and JH002) belong to Streptomyces pratensis and Streptomyces xiamenensis, respectively, are distant from the most well-known pathogenic species, and belong to two different lineages. We did not find orthogroups of protein-coding genes characteristic of scab-causing Streptomycetes shared by all known pathogenic species. Most genes involved in biosynthesis of known virulence factors are not present in the scab-causing isolates (Streptomyces sp. JH002 and Streptomyces sp. JH010). However, Tat-system substrates likely involved in pathogenicity in Streptomyces sp. JH002 and Streptomyces sp. JH010 were identified. Lastly, the presence of a putative mono-ADP-ribosyl transferase, homologous to the virulence factor scabin, was confirmed in Streptomyces sp. JH002. The described pathogenic isolates likely produce virulence factors uncommon in Streptomyces species, including a histidine phosphatase and a metalloprotease potentially produced by Streptomyces sp. JH002, and a pectinesterase, potentially produced by Streptomyces sp. JH010. Biosynthetic gene clusters (BGCs) showed the presence of clusters associated with the synthesis of medicinal compounds and BGCs potentially linked to pathogenicity in Streptomyces sp. JH010 and JH002. Interestingly, BGCs that have not been previously reported were also found. Our findings suggest that the four isolates produce novel secondary metabolites and metabolites with medicinal properties.

A Spatial-Spectral Classification Method Based on Deep Learning for Controlling Pelagic Fish Landings in Chile.

Fishing has provided mankind with a protein-rich source of food and labor, allowing for the development of an important industry, which has led to the overexploitation of most targeted fish species. The sustainable management of these natural resources requires effective control of fish landings and, therefore, an accurate calculation of fishing quotas. This work proposes a deep learning-based spatial-spectral method to classify five pelagic species of interest for the Chilean fishing industry, including the targeted Engraulis ringens, Merluccius gayi, and Strangomera bentincki and non-targeted Normanichthtys crockeri and Stromateus stellatus fish species. This proof-of-concept method is composed of two channels of a convolutional neural network (CNN) architecture that processes the Red-Green-Blue (RGB) images and the visible and near-infrared (VIS-NIR) reflectance spectra of each species. The classification results of the CNN model achieved over 94% in all performance metrics, outperforming other state-of-the-art techniques. These results support the potential use of the proposed method to automatically monitor fish landings and, therefore, ensure compliance with the established fishing quotas.

STEM and Non-STEM Misconceptions About Evolution: Findings from 5 Years of Data.

Even though it is widely held that the theory of evolution is one of the pillars of the biological sciences, as we begin the third decade of the twenty-first century, it is alarming how little we know about science, technology, engineering, and mathematics (STEM) majors and non-STEM majors' misconceptions about evolution in countries such as Brazil, Chile, Colombia, and Greece, to name a few. The situation is even more complicated if we acknowledge that contemporary educational approaches (e.g., student-centered learning) mean that students' misconceptions are one of the multiple aspects that influence the construction of meaningful learning. Here, we present a picture of Colombian STEM/non-STEM majors' misconceptions about evolution. Participants were 547 students from different STEM/non-STEM majors (278 females and 269 males, 16-24 years old). During 5 years (10 academic semesters), data were collected from students' responses to an 11-item questionnaire administered in a Colombian university. We hypothesized that the academic semester within these 5 years in which each student completed the instrument as well as respondents' age, gender, and/or major may influence their misconceptions about evolution. Results reveal that participants had a moderate understanding of evolution. Also, we found a limited understanding of microevolution among participants. Furthermore, cross-sectional analyses of differences in undergraduates' responses across demographic variables showed that despite apparent differences, these were not reliable since the differences were not statistically significant. Implications for evolution education are discussed.

Searching for the Mechanism that Mediates Mefenoxam-Acquired Resistance in Phytophthora infestans and How It Is Regulated.

Phytophthora infestans, the causal agent of late blight disease of potatoes, is mainly controlled by the use of fungicides. Isolates that are resistant to commonly used fungicides have been reported. Also, several studies show that originally mefenoxam-sensitive isolates acquire resistance to this fungicide when exposed to sublethal concentrations. This phenomenon, termed "mefenoxam-acquired resistance," has been observed in different Phytophthora species and seems to be unique to mefenoxam. In this study, we aimed to elucidate the molecular mechanism mediating this type of resistance as well as a possible regulatory process behind it. A combination of computational analyses and experimental approaches was used to identify differentially expressed genes with a potential association to the phenomenon. These genes were classified into seven functional groups. Most of them seem to be associated with a pleiotropic drug resistance (PDR) phenotype, typically involved in the expulsion of diverse metabolites, drugs, or other substances out of the cell. Despite the importance of RNA Polymerase I for the constitutive resistance of P. infestans to mefenoxam, our results indicate no clear interaction between this protein and the acquisition of mefenoxam resistance. Several small non-coding RNAs were found to be differentially expressed and specifically related to genes mediating the PDR phenotype, thus suggesting a possible regulatory process. We propose a model of the molecular mechanisms acting within the cell when P. infestans acquires resistance to mefenoxam after exposed to sublethal concentrations of the fungicide. This study provides important insights into P. infestans' cellular and regulatory functionalities.

Phenotypic and Genotypic Characterization of Phytophthora infestans Isolates Associated with Tomato and Potato Crops in Colombia.

Late blight disease, caused by the plant pathogen Phytophthora infestans, is one of the major threats for tomato and potato crops. Monitoring the populations of P. infestans is important to determine if there are changes in the sensitivity to fungicides and host preference. In this study, microsatellite markers and mitochondrial haplotypes were used to assess the genotype of isolates of P. infestans collected from tomato and potato plants in Colombia. Furthermore, sensitivity to the three fungicides cymoxanil (penetrant fungicide), mefenoxam, and fluopicolide (systemic fungicides), and tomato-potato host preference, were evaluated. Mitochondrial haplotyping showed that isolates collected on tomato were from the genetic groups Ia and Ib, while isolates collected on potatoes belonged to group IIa. Microsatellite analyses showed that isolates from tomato form two groups, including the Ib mitochondrial haplotype (which is genetically close to the US-1 clonal lineage) and the Ia haplotype (related to the EC-3 lineage), whereas Colombian isolates from potato formed a separate group. Furthermore, differences in sensitivity to fungicides were observed. Eighty-one percent of the isolates tested were resistant to mefenoxam with an EC50 >10 µg ml-1. Forty-two percent of the isolates showed an intermediate resistance to cymoxanil. The EC50 values ranged between 1 and 10 µg ml-1. For fluopicolide, 90% of the isolates were sensitive, with EC50 <1 µg ml-1. Host preference assays showed that potato isolates infected both host species. Thus, isolates that infect potatoes may pose a risk for tomato crops nearby.

Using the Controversy over Human Race to Introduce Students to the Identification and the Evaluation of Arguments.

The identification and the evaluation of arguments are fundamental elements of critical thinking. However, the explicit promotion of these elements is virtually absent from university science courses. Much of the reason for this is that in most universities, across nearly all disciplines, instructors are required to see the conceptual content coverage of the syllabus as a priority. Moreover, lack of preparation and the fact that critical thinking activities are time-consuming rapidly reduce the interest of many instructors to include them in their courses. Here, we describe the use of a dialogue-based critical thinking classroom scenario (CTCS). The study used a mixed-methods approach with both quantitative and qualitative analyses of questionnaire responses. One hundred and seventeen undergraduates (73 females; 44 males; ages 16-24 years), enrolled in an introductory science course in Colombia, were asked to identify and evaluate arguments regarding a dialogue between two scientists who explore the controversial question of whether or not the concept of race is applicable to humans. It was found that the dialogue-based CTCS provided students with opportunities to identify and evaluate arguments both for and against the question and to make informed decisions about whether or not the concept of race in humans is biologically meaningful. Moreover, analyses of responses to closed-ended and open-ended questions revealed that more than half the participants were able to evaluate arguments in a fair-minded way. Practical implications for the cultivation of critical thinking skills in higher education and further research are discussed.

A whole genome duplication drives the genome evolution of Phytophthora betacei, a closely related species to Phytophthora infestans.

BACKGROUND: Pathogens of the genus Phytophthora are the etiological agents of many devastating diseases in several high-value crops and forestry species such as potato, tomato, cocoa, and oak, among many others. Phytophthora betacei is a recently described species that causes late blight almost exclusively in tree tomatoes, and it is closely related to Phytophthora infestans that causes the disease in potato crops and other Solanaceae. This study reports the assembly and annotation of the genomes of P. betacei P8084, the first of its species, and P. infestans RC1-10, a Colombian strain from the EC-1 lineage, using long-read SMRT sequencing technology. RESULTS: Our results show that P. betacei has the largest sequenced genome size of the Phytophthora genus so far with 270 Mb. A moderate transposable element invasion and a whole genome duplication likely explain its genome size expansion when compared to P. infestans, whereas P. infestans RC1-10 has expanded its genome under the activity of transposable elements. The high diversity and abundance (in terms of copy number) of classified and unclassified transposable elements in P. infestans RC1-10 relative to P. betacei bears testimony of the power of long-read technologies to discover novel repetitive elements in the genomes of organisms. Our data also provides support for the phylogenetic placement of P. betacei as a standalone species and as a sister group of P. infestans. Finally, we found no evidence to support the idea that the genome of P. betacei P8084 follows the same gene-dense/gense-sparse architecture proposed for P. infestans and other filamentous plant pathogens. CONCLUSIONS: This study provides the first genome-wide picture of P. betacei and expands the genomic resources available for P. infestans. This is a contribution towards the understanding of the genome biology and evolutionary history of Phytophthora species belonging to the subclade 1c.

The type VI secretion system of Xanthomonas phaseoli pv. manihotis is involved in virulence and in vitro motility.

BACKGROUND: The type VI protein secretion system (T6SS) is important in diverse cellular processes in Gram-negative bacteria, including interactions with other bacteria and with eukaryotic hosts. In this study we analyze the evolution of the T6SS in the genus Xanthomonas and evaluate its importance of the T6SS for virulence and in vitro motility in Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of bacterial blight in cassava (Manihot esculenta). We delineate the organization of the T6SS gene clusters in Xanthomonas and then characterize proteins of this secretion system in Xpm strain CIO151. RESULTS: We describe the presence of three different clusters in the genus Xanthomonas that vary in their organization and degree of synteny between species. Using a gene knockout strategy, we also found that vgrG and hcp are required for maximal aggressiveness of Xpm on cassava plants while clpV is important for both motility and maximal aggressiveness. CONCLUSION: We characterized the T6SS in 15 different strains in Xanthomonas and our phylogenetic analyses suggest that the T6SS might have been acquired by a very ancient event of horizontal gene transfer and maintained through evolution, hinting at their importance for the adaptation of Xanthomonas to their hosts. Finally, we demonstrated that the T6SS of Xpm is functional, and significantly contributes to virulence and motility. This is the first experimental study that demonstrates the role of the T6SS in the Xpm-cassava interaction and the T6SS organization in the genus Xanthomonas.

Towards Covid-19 Literacy: Investigating the Literacy Levels of University Students in Colombia.

Covid-19 literacy, induced by the coronavirus disease (2019), is characterized as the understanding of Covid-19 as well as informed decisions based upon this understanding. This type of literacy is closely related to health literacy, scientific literacy, and scientific media literacy. It may be obvious to say that Covid-19 literacy is a key factor for governments to effectively manage the Covid-19 transition. However, lack of literature exists about Covid-19 literacy among university students. Therefore, the current study aimed to determine the Covid-19 literacy level among 4168 students from a Colombian university. The data were derived from students' responses to a 25-item anonymous online self-reporting questionnaire. We found that 21-25-year age group, graduate students, students enrolled prior to 2015, and medical students had a significantly higher mean score. Moreover, the Internet (86.8%) was the most popular source of information from which participants gained most information regarding Covid-19. Furthermore, 58.5% of the participants considered health workers as a source that can provide accurate information. Most importantly, the findings reveal the students' knowledge about (1) the role of an eventual process of vaccination, (2) the test currently used as diagnostic for Covid-19, and (3) the fatality rate, three aspects of Covid-19 literacy that deserve more attention. The findings provide a useful basis for the formulation of policies and concrete actions in improving Covid-19 literacy.

Salifodinibacter halophilus gen. nov., sp. nov., a halophilic gammaproteobacterium in the family Salinisphaeraceae isolated from a salt mine in the Colombian Andes.

Two morphologically similar halophilic strains, named USBA 874 and USBA 960T, were isolated from water and sediment samples collected from the Zipaquirá salt mine in the Colombian Andes. Both isolates had non-spore-forming, Gram-stain-negative and motile cells that grew aerobically. The strains grew optimally at 30 °C, pH 7.0 and with 25 % NaCl (w/v). The isolates showed almost identical 16S rRNA gene sequences (99.0 % similarity). The predominant quinones of USBA-960T were Q-8, Q-7 and Q-9. The major cellular fatty acids were C19 : 0 cyclo ω8c, C18 : 0 and C16 : 0. According to 16S rRNA gene sequencing, the closest phylogenetic relatives are Salinisphaera species (similarity between 93.6 and 92.3 %), Abyssibacter profundi OUC007T (88.6 %) and Oceanococcus atlanticus 22II-S10r2T (88.7 %). In addition, the result of genome blast distance phylogeny analysis between strains USBA 874 and USBA 960T, Salinisphaera halophila (YIM 95161T), Salinisphaera shabanensis (E1L3AT), Salinisphaera orenii (MK-B5T) and Salinisphaera japonica (YTM-1T) was 18.5 %. Other in silico species delineation analyses also showed low identity such as ANIb and ANIm values (<69.0 and <84.0 % respectively), TETRA (<0.81) and AAI values (<0.67). Genome sequencing of USBA 960T revealed a genome size of 2.47 Mbp and a G+C content of 59.71 mol%. Phylogenetic analysis of strains USBA 874 and USBA 960T indicated that they formed a different lineage within the family Salinisphaeraceae. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA-DNA relatedness values, along with identity at whole genome level, it can be concluded that strains USBA 960T and USBA 874 represent a novel genus of the family Salinisphaeraceae and the name Salifodinibacter halophilus gen. nov., sp. nov. is proposed. The type strain is USBA 960T (CMPUJ U095T=CECT 30006T).

Genomic Variability of Phytophthora palmivora Isolates from Different Oil Palm Cultivation Regions in Colombia.

Palm oil is the most consumed vegetable oil globally, and Colombia is the largest palm oil producer in South America and fourth worldwide. However, oil palm plantations in Colombia are affected by bud rot disease caused by the oomycete Phytophthora palmivora, leading to significant economic losses. Infection processes by plant pathogens involve the secretion of effector molecules, which alter the functioning or structure of host cells. Current long-read sequencing technologies provide the information needed to produce high-quality genome assemblies, enabling a comprehensive annotation of effectors. Here, we describe the development of genomic resources for P. palmivora, including a high-quality genome assembly based on long and short-read sequencing data, intraspecies variability for 12 isolates from different oil palm cultivation regions in Colombia, and a catalog of over 1,000 candidate effector proteins. A total of 45,416 genes were annotated from the new genome assembled in 2,322 contigs adding to 165.5 Mbp, which represents an improvement of two times more gene models, 33 times better contiguity, and 11 times less fragmentation compared with currently available genomic resources for the species. Analysis of nucleotide evolution in paralogs suggests a recent whole-genome duplication event. Genetic differences were identified among isolates showing variable virulence levels. We expect that these novel genomic resources contribute to the characterization of the species and the understanding of the interaction of P. palmivora with oil palm and could be further exploited as tools for the development of effective strategies for disease control.

Two Clonal Species of Phytophthora Associated to Solanaceous Crops Coexist in Central and Southern Colombia.

In Colombia, late blight is considered one of the most limiting diseases on potato and tomato production. Recently, a new Phytophthora species, P. betacei, was described infecting tree tomato crops in the south of Colombia. However, the distribution and the host range of this new emerging pathogen in the country are unknown. The main aims of this study were to determine if this novel species is confined to the south of Colombia, to assess if P. betacei represents a genetically uniform clone across Colombia and to determine if in all regions there is a clear differentiation between the two Phytophthora species. Therefore, we characterized Phytophthora isolates obtained from tree tomato and potato crops in a central region of Colombia and compared them with the strains from the south. Initially, we evaluated the genetic differentiation among Phytophthora strains obtained from tree tomato and potato crops using simple sequence repeat markers. Results showed a strong population structure between P. infestans and P. betacei. However, we did not detect any genetic differentiation within P. infestans or P. betacei populations from different regions. Furthermore, we detected significant morphological differences among the species based on growth and sporangial morphology measurements. We also showed that strains of Phytophthora spp. are predominantly of the A1 mating type and belong to EC-1 and EC-3 clonal lineages for P. infestans and P. betacei, respectively. Our results describe the expanded geographical range of the new species of P. betacei in the central region of Colombia.

Differential Susceptibility of Tree Tomato (Solanum betaceum) Cultivars to Late Blight Caused by Phytophthora betacei.

Host-pathogen interactions of a new species of Phytophthora, causal agent of late blight of tree tomato (Solanum betaceum Cav.), identified as Phytophthora betacei, were investigated with four different cultivars. Thirty-six P. betacei isolates, collected from southern Colombia between 2008 and 2009, were used to inoculate common tree tomato cultivars, Común, Híbrido, Injerto, and Holandés. Data on incubation and latent periods as well as infection efficiency, lesion development, and total sporulation were collected via detached leaf assays. Significant differences in susceptibility, based on the parameters measured, were observed. Común was the most susceptible cultivar, followed by Injerto, Híbrido, and Holandés. The mean incubation period was lowest for Común at 125.6 h post-inoculation (hpi) and highest for Híbrido at 139.4 hpi. No significant differences in latent period were observed. All 36 isolates produced necrotic lesions on Común, and 33, 24, and 21 caused infection on Injerto, Híbrido, and Holandés, respectively. Two isolates were able to cause infection only on Común, and 13 isolates were able to infect all four cultivars. Infection efficiency was significantly higher for the cultivar Común, followed by Injerto, Híbrido, and Holandés. Average lesion size was larger on Común than on any other cultivar. An inverse relationship of lesion size and total sporulation was observed. Común had significantly lower total sporulation than Híbrido and Holandés, which had the smallest average lesion sizes. These data show variation in pathogenicity of P. betacei isolates, under controlled conditions, and differential susceptibility of four distinct S. betaceum cultivars.

Is the Phenomenon of Mefenoxam-Acquired Resistance in Phytophthora infestans Universal?

Phytophthora infestans is the causal agent of late blight disease of potatoes and tomatoes. This disease causes devastating economic losses each year, and control is mainly achieved by the use of fungicides. Unfortunately, populations of P. infestans resistant to fungicides have been documented. Furthermore, studies have reported that sensitive isolates to the phenylamide fungicide, mefenoxam, become less sensitive in vitro after a single passage through sublethal concentrations of fungicide-amended medium. The first objective of this study was to investigate if isolates of P. infestans are capable of acquiring resistance to two additional systemic fungicides, fluopicolide (benzamide) and cymoxanil (cyanoacetamide-oxime). In contrast to the situation with mefenoxam, exposure of isolates to sublethal concentrations of fluopicolide and cymoxanil did not induce reduced sensitivity to these two fungicides. The second objective was to assess if reduced sensitivity to mefenoxam could occur in naturally sensitive isolates of other Phytophthora species and of Phytopythium sp., another oomycete plant pathogen. All Phytophthora spp. assessed (P. infestans, P. betacei, and P. pseudocryptogea) as well as Phytopythium sp. acquired resistance to mefenoxam after previous exposure through medium containing 1 µg ml-1 of mefenoxam. Interestingly, isolate 66 of Phytopythium sp. and the isolate of P. pseudocryptogea tested do not seem to be acquiring resistance to mefenoxam after exposure to medium containing 5 µg ml-1 of this fungicide. The tested isolates of P. palmivora and P. cinnamomi were extremely sensitive to mefenoxam, and thus it was not possible to perform a second transfer to access acquisition of resistance to this fungicide.

Bioactive Potential of Extracts of Labrenzia aggregata Strain USBA 371, a Halophilic Bacterium Isolated from a Terrestrial Source.

Previous studies revealed the potential of Labrenzia aggregata USBA 371 to produce cytotoxic metabolites. This study explores its metabolic diversity and compounds involved in its cytotoxic activity. Extracts from the extracellular fraction of strain USBA 371 showed high levels of cytotoxic activity associated with the production of diketopiperazines (DKPs). We purified two compounds and a mixture of two other compounds from this fraction. Their structures were characterized by 1D and 2D nuclear magnetic resonance (NMR). The purified compounds were evaluated for additional cytotoxic activities. Compound 1 (cyclo (l-Pro-l-Tyr)) showed cytotoxicity to the following cancer cell lines: breast cancer 4T1 (IC50 57.09 ± 2.11 µM), 4T1H17 (IC50 40.38 ± 1.94), MCF-7 (IC50 87.74 ± 2.32 µM), murine melanoma B16 (IC50 80.87 ± 3.67), human uterus sarcoma MES-SA/Dx5 P-pg (-) (IC50 291.32 ± 5.64) and MES-SA/Dx5 P-pg (+) (IC50 225.28 ± 1.23), and murine colon MCA 38 (IC50 29.85 ± 1.55). In order to elucidate the biosynthetic route of the production of DKPs and other secondary metabolites, we sequenced the genome of L. aggregata USBA 371. We found no evidence for biosynthetic pathways associated with cyclodipeptide synthases (CDPSs) or non-ribosomal peptides (NRPS), but based on proteogenomic analysis we suggest that they are produced by proteolytic enzymes. This is the first report in which the cytotoxic effect of cyclo (l-Pro-l-Tyr) produced by an organism of the genus Labrenzia has been evaluated against several cancer cell lines.

Gene regulatory networks on transfer entropy (GRNTE): a novel approach to reconstruct gene regulatory interactions applied to a case study for the plant pathogen Phytophthora infestans.

BACKGROUND: The increasing amounts of genomics data have helped in the understanding of the molecular dynamics of complex systems such as plant and animal diseases. However, transcriptional regulation, although playing a central role in the decision-making process of cellular systems, is still poorly understood. In this study, we linked expression data with mathematical models to infer gene regulatory networks (GRN). We present a simple yet effective method to estimate transcription factors' GRNs from transcriptional data. METHOD: We defined interactions between pairs of genes (edges in the GRN) as the partial mutual information between these genes that takes into account time and possible lags in time from one gene in relation to another. We call this method Gene Regulatory Networks on Transfer Entropy (GRNTE) and it corresponds to Granger causality for Gaussian variables in an autoregressive model. To evaluate the reconstruction accuracy of our method, we generated several sub-networks from the GRN of the eukaryotic yeast model, Saccharomyces cerevisae. Then, we applied this method using experimental data of the plant pathogen Phytophthora infestans. We evaluated the transcriptional expression levels of 48 transcription factors of P. infestans during its interaction with one moderately resistant and one susceptible cultivar of yellow potato (Solanum tuberosum group Phureja), using RT-qPCR. With these data, we reconstructed the regulatory network of P. infestans during its interaction with these hosts. RESULTS: We first evaluated the performance of our method, based on the transfer entropy (GRNTE), on eukaryotic datasets from the GRNs of the yeast S. cerevisae. Results suggest that GRNTE is comparable with the state-of-the-art methods when the parameters for edge detection are properly tuned. In the case of P. infestans, most of the genes considered in this study, showed a significant change in expression from the onset of the interaction (0 h post inoculum - hpi) to the later time-points post inoculation. Hierarchical clustering of the expression data discriminated two distinct periods during the infection: from 12 to 36 hpi and from 48 to 72 hpi for both the moderately resistant and susceptible cultivars. These distinct periods could be associated with two phases of the life cycle of the pathogen when infecting the host plant: the biotrophic and necrotrophic phases. CONCLUSIONS: Here we presented an algorithmic solution to the problem of network reconstruction in time series data. This analytical perspective makes use of the dynamic nature of time series data as it relates to intrinsically dynamic processes such as transcription regulation, were multiple elements of the cell (e.g., transcription factors) act simultaneously and change over time. We applied the algorithm to study the regulatory network of P. infestans during its interaction with two hosts which differ in their level of resistance to the pathogen. Although the gene expression analysis did not show differences between the two hosts, the results of the GRN analyses evidenced rewiring of the genes' interactions according to the resistance level of the host. This suggests that different regulatory processes are activated in response to different environmental cues. Applications of our methodology showed that it could reliably predict where to place edges in the transcriptional networks and sub-networks. The experimental approach used here can help provide insights on the biological role of these interactions on complex processes such as pathogenicity. The code used is available at https://github.com/jccastrog/GRNTE under GNU general public license 3.0.

Determining Whether Geographic Origin and Potato Genotypes Shape the Population Structure of Phytophthora infestans in the Central Region of Colombia.

Pathogen variation plays an important role in the dynamics of infectious diseases. In this study, the genetic variation of 279 Phytophthora infestans isolates was assessed using a combination of 12 microsatellite simple-sequence repeat markers. Isolates were collected from 11 different potato cultivars in 11 different geographic localities of the central region of Colombia. The objective of this study was to determine whether populations were differentiated by host genotype or geographic origin. Within a single clonal lineage, EC-1, 76 genotypes were detected. An analysis of molecular variance attributed most of the variation to differences within host genotypes rather than among the host genotypes, suggesting that host cultivars do not structure the populations of the pathogen. Furthermore, the lack of a genetic population structure according to the host cultivar was confirmed by all of the analyses, including the Bayesian clustering analysis and the minimum spanning network that used the Bruvo genetic distance, which suggested that there are no significant barriers to gene flow for P. infestans among potato cultivars. According to the geographic origin, the populations of P. infestans were also not structured, and most of the variation among the isolates was attributed to differences within localities. Only some but not all localities in the north and west of the central region of Colombia showed some genetic differentiation from the other regions. The absence of sexual reproduction of this pathogen in Colombia was also demonstrated. Important insights are discussed regarding the genetic population dynamics of the P. infestans populations of the central region of Colombia that were provided by the results. In Colombia, there is a high genetic variation within the EC-1 clonal lineage with closely related genotypes, none dominant, that coexist in a wide geographic area and on several potato cultivars.

An Optimized Microsatellite Scheme for Assessing Populations of Xanthomonas phaseoli pv. manihotis.

Diverse molecular markers have been used to analyze the genetic diversity of plant pathogens. Compared with traditional fingerprinting methods, multiple loci variable number of tandem repeat analyses (MLVAs) have gained importance recently due to their reproducibility, high discriminatory power, ease of performance, low cost, and throughput potential. These characteristics are desirable for continuous pathogen monitoring, especially for pathogens with relatively low genetic diversity, and for disease epidemiology studies. Genetic diversity studies of Xanthomonas phaseoli pv. manihotis, which is the causal agent of cassava bacterial blight, have shown variability and changes in the bacterial population over time. Thus, an easy and fast method needs to be developed to type populations of this pathogen in different countries of the world, especially on small scales. In this study, we developed an MLVA scheme to analyze X. phaseoli pv. manihotis variability on a local scale. The MLVA-15 scheme comprises 15 variable number of tandem repeat loci grouped into four multiplex polymerase chain reaction pools. We showed that the MLVA-15 scheme had slightly higher discriminatory ability at the locality level when compared with amplified fragment length polymorphisms. The MLVA-15 scheme allowed for an accurate determination of the number of genotypes in the sample and showed reproducibility and portability. Additionally, this scheme could be used to analyze numerous strains in a reasonable timeframe. The MLVA-15 scheme was highly specific to X. phaseoli but up to eight tandem repeat loci could be amplified from other Xanthomonas spp. Finally, we assessed the utility of the scheme for analyses of X. phaseoli pv. manihotis genetic variability in the Colombian Caribbean region. MLVA-15 distinguished 88.9% of the haplotypes in our sample. Strains originating from the same field and isolated at the same time could be discriminated. In this study, the advantages of the MLVA-15 scheme targeting 6- or 7-bp repeats were demonstrated. Moreover, this scheme was a fast method that was appropriate for routine monitoring of X. phaseoli pv. manihotis populations on a local scale and, thus, was useful for addressing epidemiological questions.