Biology subjects

Pena, L.

Publications and source records attributed to Pena, L..

6 recordsLinked to original sources

bioRxiv2026

Distinct foraging goals shape floral resource use in a generalist solitary bee

A central challenge in characterizing species niches is ensuring that foraging data accurately capture both the resources used and their relative importance, and the role of resource abundance in shaping foraging patterns. Most studies infer diet breadth and resource-use patterns from observational records, yet such data can mask resource-specific decisions when animals forage with different goals. Here, we test this experimentally using individually identifiable bees in controlled resource communities to quantify foraging decisions between nectar (for sustenance) and pollen (for offspring provisioning). Combining observations, pollen DNA metabarcoding, and pollen microscopy, we show that observed visitation patterns misrepresent the floral resources most important for offspring provisioning, which ultimately determines offspring survival and population persistence. We further show that interaction patterns are structured from processes beyond resource abundance. Our results demonstrate that commonly used observational approaches can mischaracterize diet breadth, potentially challenging conclusions about species generalization.

ecology↗

bioRxiv2026

Mechanosensitive channels dominate the minimal ion channelrepertoire in prokaryotes

The eukaryotic genomes encode hundreds of proteins that function as ion channels and transporters. Essential for sustaining life, these proteins mediate the movement of inorganic ions (e.g., K+, Na+, Cl-, and Ca2+) across the plasma membrane according to their electrochemical gradients. In multicellular organisms, a diverse array of ion channels contributes to the maintenance of the resting membrane potential, the regulation of pH, osmolarity, and cell volume, and the control of secretion, electrical excitability, and synaptic activity, among many other fundamental physiological processes. Although independent evolutionary origins have been proposed for several ion channel families, their relative hierarchical importance for cellular viability remains poorly understood. To advance our knowledge of ion channel evolutionary history, we focused on determining the minimal combination of permeabilities that allows cellular viability. To this end, we conducted a survey of representative prokaryotes with small genomes across bacterial and archaeal phyla. By focusing on the smallest genomes, our approach enabled the identification of five ion channel architectures shared among prokaryotes. Among these, non-selective mechanosensitive channels (MscS and MscL) are the most abundant, followed by CLC-type channels, RCK-containing 2TM potassium channels, and proton channels of the MotA/TolQ/ExbB family. The conservation of the mechanosensitive protein architecture across archaeal and bacterial membranes suggests that the capacity to monitor physical membrane integrity predates the requirements for electrical communication.

biophysics↗

bioRxiv2025

Chromosome-Scale Genome Assembly of Australian Finger Lime and Resequencing Reveal the Hidden Diversity of Oceanian Citrus

Oceanian citrus species, including wild taxa native to Australia and Papua New Guinea, form a genetically distinct clade within the Citrus L. (1753) genus. These species remain largely underexplored, despite their adaptation to diverse environments and relevance for citrus improvement. To support their use in breeding and evolutionary studies, we generated a high-quality, Chromosome-scale genome assembly of an Australian finger lime accession (SRA 1002), a natural interspecific hybrid. The genome was assembled using long-read sequencing, optical mapping, and a high-density genetic map, resulting in nine pseudomolecules covering over 97% of the genome. Using this reference, we analyzed whole-genome resequencing data from 132 accessions representing the diversity of Asian and Oceanian citrus. Variant calling across the dataset produced a high-resolution catalogue of single nucleotide polymorphisms (SNPs) and derived database of SNP fully discriminant of 20 Citrus species (DSNPs), enabling detailed exploration of inter- and intra-specific diversity. The data reveal a strong population structure within the group with clear heterozygosity variation between ancestral species and admixed accessions, reflecting their complex evolutionary history and hybridization patterns. This study provides the first integrated genomic framework for Oceanian citrus diversity, offering essential tools for downstream applications in citrus breeding, conservation, and evolutionary genomics. The resources generated lay the groundwork for future association studies and the targeted introgression of beneficial traits into cultivated citrus.

plant biology↗

bioRxiv2025

Contrasting needle physiological strategies to soil nutrient scarcity in radiata pine plantations

Intensive European forestry practices contribute to soil degradation and nutrient depletion, compromising tree health and ecosystem stability. However, the influence of soil nutrient scarcity on tree physiological responses during drought remains unclear, particularly in Pinus radiata D. Don plantations, where it may impair needle function and overall tree health. We investigated how soil nutrient availability influences leaf-level physiological strategies during drought by comparing same-aged needles from two P. radiata stands with contrasting management stages and ages: (i) trees ({approx}20 years), likely to be clear-cut at 30-35 years (herein managed), and (ii) trees (>45 years) not clear-cut at the typical rotation age (herein abandoned). During the severe summer drought of 2022, both stands exhibited downregulation of the photosynthetic apparatus, indicating impaired photosynthetic performance under drought. However, their leaf-physiological responses to nutrient scarcity diverged. Managed trees exhibited dependence on soil nutrients, with reduced photosynthetic performance under nutrient-poor conditions. In contrast, abandoned trees showed relative independence from soil nutrients, maintaining photosynthetic function even under nutrient-poor conditions. This highlights a trade-off: younger, managed trees may enhance photosynthesis under optimal nutrient conditions but are more susceptible to nutrient imbalances and environmental stress. In turn, older, abandoned trees appeared to buffer the effects of drought and nutrient scarcity through age-related physiological traits. Our findings underscore the physiological value of mature stands. Furthermore, higher soil organic carbon and vegetation diversity in abandoned stands suggest that management cessation may enhance long-term ecosystem resilience. These results emphasise the importance of integrating soil-leaf interactions into sustainable forest management.

plant biology↗

bioRxiv2024

α-Copaene is a potent repellent against the Asian Citrus Psyllid Diaphorina citri

The Asian Citrus Psyllid (ACP), Diaphorina citri, severely threatens citrus production worldwide by transmitting the greening(= Huanglongbing)-causing bacterium Candidatus Liberibacter asiaticus. There is growing evidence that the push-pull strategy is suitable to partially mitigate HLB by repelling ACP with transgenic plants engineered to produce repellents and attracting the vector to plants with a minimal disease transmission rate. Species that pull ACP away from commercial citrus plants have been identified, and transgenic plants that repel ACP have been developed. The concept of a repellent-producing plant was first demonstrated with an Arabidopsis line engineered to overexpress a gene controlling the synthesis of {beta}-caryophyllene and other sesquiterpenes. We have analyzed the volatile organic compounds released by this Arabidopsis line and identified -humulene, -copaene, and trace amounts of {beta}-elemene, in addition to {beta}-caryophyllene. Behavioral measurements demonstrated that -copaene repels ACP at doses ca. 100x lower than those needed for {beta}-caryophyllene repellence. In contrast, -humulene is innocuous at the level emitted by the transgenic plant. We confirmed that a mixture of the three sesquiterpenes in the ratio 100:10:1 repels ACP. Likewise, a commercial sample of refined copaiba oil containing the three sesquiterpenes, in a proportion similar to that in the transgenic plant, repelled ACP.

ecology↗

bioRxiv2021

The molecular interplay of the establishment of an infection - gene expression of Diaphorina citri gut and Candidatus Liberibacter asiaticus

Candidatus Liberibacter asiaticus (CLas) is one the causative agents of greening disease in citrus, an unccurable, devastating disease of citrus worldwide. CLas is vectored by Diaphorina citri, and the understanding of the molecular interplay between vector and pathogen will provide additional basis for the development and implementation of successful management strategies. We focused in the molecular interplay occurring in the gut of the vector, a major barrier for CLas invasion and colonization. We investigated the differential expression of vector and CLas genes by analyzing a de novo reference metatranscriptome of the gut of adult psyllids fed of CLas-infected and healthy citrus plants for 1-2, 3-4 and 5-6 days. CLas regulates the immune response of the vector affecting the production of reactive species of oxygen and nitrogen, and the production of antimicrobial peptides. Moreover, CLas overexpressed peroxiredoxin in a protective manner. The major transcript involved in immune expression was related to melanization, a CLIP-domain serine protease we believe participates in the wounding of epithelial cells damaged during infection, which is supported by the down-regulation of pangolin. We also detected that CLas modulates the gut peristalsis of psyllids through the down-regulation of titin, reducing the elimination of CLas with faeces. The up-regulation of the neuromodulator arylalkylamine N-acetyltransferase implies CLas also interferes with the double brain-gut communication circuitry of the vector. CLas colonizes the gut by expressing two Type IVb pilin flp genes and several chaperones that can also function as adhesins. We hypothesized biofil formation occurs by the expression of the cold shock protein of CLas. We also describe the interplay during cell invasion and modification, and propose mechanisms CLas uses to invade the host hemocel. We identified several specific targets for the development of strategies directed to interfere with the successful utilization of the psyllid vector by this pathogen. Author SummaryHuanglongbing (HLB) or greening is an incurable disease causing severe damage to citrus production, making citrus industrial activity unsustainable in several countries around the world. HLB is caused by three species of Candidatus Liberibacter. Ca. L. asiaticus (CLas), vectored by the psyllid Diaphorina citri, is the prevalent species. Attempts to apply new technologies in the development of strategies for disease and pest management are been made. However, we still miss basic information on this system to efficiently apply the current technologies and envisage the implementation of new approaches for pest control, despite the relevant scientific contribution available. One major gap is regarded to the molecular interplay between CLas and its vector. We focused our attention in the molecular interplay occurring at the first relevant interaction of CLas and D. citri, represented by the gut barrier. We report the transcriptional activity of CLas during the invasion and establishment of the infection in the gut of the vector, as well as the transcriptional activity of the vector in response to the infection. We identified several host genes that are targeted and regulated by CLas as well as several CLas genes that are promising targets for the application of new management strategies.

pathology↗