Biology subjects

Gamboa, S.

Publications and source records attributed to Gamboa, S..

4 recordsLinked to original sources

bioRxiv2026

Population structure of Phytophthora infestans collected from potatoes in Ecuador, Colombia, Peru, Bolivia and Uruguay

Late blight, a destructive disease affecting potatoes, is caused by the oomycete Phytophthora infestans and remains a major threat to potato production worldwide. Understanding the population structure of this pathogen is essential for effective disease management. We examined the genetic structure of South American P. infestans populations using 182 isolates: 97 from Bolivia and southern Peru, 14 from Colombia, 57 from Ecuador (1993-2022), and 14 from Uruguay. The isolates were characterized by clonal lineage, mitochondrial haplotype, and mating type using multilocus genotypes based on microsatellite (SSR) markers. In Bolivia, only the lineage/haplotype 2A1/Ia was identified, whereas Peru exhibited both 2A1/Ia and EC1/IIa, all of which were mating type A1. Puno was the sole department where both lineages were present. In historical Ecuadorian populations, we found US1/Ib and EC1/IIa (P. infestans), as well as EC2/Ic and EC3/Ia (Phytophthora andina), while recent populations showed only US1. In Colombia, EC1/IIa and a distinct clonal lineage (CO4/Ia) were identified within the present dataset. In Uruguay, 2A1/Ia was predominant. These results provide updated insights into the genetic diversity and geographic distribution of P. infestans across South America and highlight the importance of continued regional surveillance for improved late blight management.

plant biology↗

bioRxiv2025

Population structure of Phytophthora infestans collected from potatoes in Guatemala and Honduras

Phytophthora infestans, the causal agent of late blight, remains a major constraint to potato production worldwide. In Central America, particularly in Guatemala and Honduras, information on the pathogen's population structure is limited despite its economic importance and reliance on imported seed potatoes. This study characterized the population structure of P. infestans in potato fields in Guatemala and Honduras using microsatellite markers, mitochondrial haplotypes, and mating type analyses. Four SSR-defined groups were identified, three corresponding to the previously described clonal lineages EU13A2, NI_1, and US8A2, and one putative group designated CeA (Central America). The detection of EU13A2, a lineage first reported in Europe and subsequently in Asia, indicates its establishment in Central America. All successfully characterized isolates exhibited the Ia mitochondrial haplotype, indicating limited mitochondrial diversity despite substantial nuclear SSR variation. AMOVA revealed significant genetic differentiation between Honduras and Guatemala, accounting for 24.43% of the total SSR variation (p = 0.022). Significant linkage disequilibrium was detected within the analyzed populations. The occurrence of genetically distinct P. infestans groups across the study area highlights the importance of monitoring transboundary pathogen movement in Central America.

pathology↗

bioRxiv2023

Early Jurassic origin of avian endothermy and thermophysiological diversity in Dinosauria

A fundamental question in dinosaur evolution is how they adapted to substantial long-term shifts in Earth System during the Mesozoic and when they developed environmentally independent, avian-style acclimatization due to the evolution of an endothermic physiology. Combining fossil occurrences with macroevolutionary and paleoclimatic models, we unveil distinct evolutionary pathways in the main dinosaur lineages: ornithischians and theropods diversified across broader climatic landscapes, trending toward cooler niches. An Early Jurassic shift to colder climates in Theropoda suggests an early adoption of endothermic thermophysiology. Conversely, sauropodomorphs exhibited prolonged climatic conservatism associated with higher thermal conditions. Paleo-biome mapping emphasizes temperature, rather than plant productivity, as the primary driver of this pattern, suggesting poikilothermic physiology with a stronger dependence on higher temperatures in sauropods since the Early Jurassic. One-Sentence SummaryDinosaur climatic evolution reveals early endothermy emergence in theropods, ornithischians but heterotherm sauropodomorphs.

paleontology↗

bioRxiv2022

Small-spored Alternaria spp. (section Alternaria) are common on wild tomato species

The wild relatives of modern tomato crops are native to South America. These plants occur in habitats as different as the Andes and the Atacama Desert and are to some degree all susceptible to fungal pathogens of the genus Alternaria. Alternaria is a large genus. On tomato, several species cause early blight, leaf spot, and other diseases. We collected Alternaria-like infection lesions from the leaves of eight wild tomato species from Chile and Peru. Using molecular barcoding markers, we characterized the pathogens. The infection lesions were caused predominantly by small-spored species of Alternaria of the section Alternaria, like A. alternata, but also by Stemphylium spp., Alternaria spp. from the section Ulocladioides, and other related species. Morphological observations and an infection assay confirmed this. Comparative genetic diversity analyses show a larger diversity in this wild system than in studies of cultivated Solanum species. As A. alternata has been reported to be an increasing problem on cultivated tomato, investigating the evolutionary potential of this pathogen is not only interesting to scientists studying wild plant-pathosystems. It could also inform crop protection and breeding programs to be aware of potential epidemics caused by species still confined to South America.

microbiology↗