Biology subjects

Tena, A.

Publications and source records attributed to Tena, A..

3 recordsLinked to original sources

bioRxiv2025

Tamarixia citricola Hansson and Guerrieri sp. nov. (Hymenoptera: Eulophidae): a new parasitoid of Diaphorina citri Kuwayamava (Hemiptera: Psyllidae) found during a classical biological control program in Cyprus

Asian citrus psyllid, Diaphorina citri, is a major global pest because it is the primary vector of Candidatus Liberibacter spp., the causal agents of huanglongbing (HLB), a lethal citrus disease. Following the detection of D. citri in Cyprus in 2023, the first record of this pest in the European Union, a classical biological control program targeting this pest was initiated in spring 2024 using the parasitoid Tamarixia radiata imported from California, USA. During field surveys in summer 2024, parasitized D. citri nymphs were found in orchards where no T. radiata releases had been made. These findings suggested the possible presence of native or unintentionally introduced parasitoids, or a rapid spread of T. radiata into new areas. To determine the identity of parasitoids associated with D. citri in Cyprus, an integrative approach was adopted combining field observations, molecular analyses of the COI gene, and morphological analyses. Tamarixia radiata recovered from Cyprus field sites matched reference sequences of parasitoids from California. However, other specimens were genetically and morphologically distinct and represented a new species. The new species is described here as Tamarixia citricola Hansson & Guerrieri sp. nov. Taxonomic diagnoses and characters for separating both Tamarixia species associated with D. citri are provided. Results presented here indicate the coexistence of both T. radiata (introduced) and T. citricola (likely autochthonous) in Cyprus citrus orchards. This finding has important implications for future biological control strategies and quarantine measures for D. citri in the Mediterranean basin.

zoology↗

bioRxiv2020

Sex, males, and hermaphrodites in the scale insect Icerya purchasi

Androdioecy (the coexistence of males and hermaphrodites) is a rare mating system for which the evolutionary dynamics are poorly understood. Here we study the only presumed case of androdioecy in insects, found in the cottony cushion scale, Icerya purchasi. In this species, female-like hermaphrodites have been shown to produce sperm and self-fertilize. However, rare males are sometimes observed too. In a large population-genetic analysis, we show for the first time that although self-fertilization appears to be the primary mode of reproduction, rare outbreeding events between males and hermaphrodites do occur, and we thereby confirm androdioecy as the mating system of I. purchasi. Thus, this insect appears to have the colonization advantages of a selfing organism while also benefitting from periodic reintroduction of genetic variation through outbreeding with males.

evolutionary biology↗

bioRxiv2019

Induction of Recurrent Break Cluster Genes in Neural Progenitor Cells Differentiated from Embryonic Stem Cells In Culture

Mild replication stress enhances appearance of dozens of robust recurrent genomic break clusters, termed RDCs, in cultured primary mouse neural stem and progenitor cells (NSPCs). Robust RDCs occur within genes ("RDC-genes") that are long and have roles in neural cell communications and/or have been implicated in neuropsychiatric diseases or cancer. We sought to develop an in vitro approach to determine whether specific RDC formation is associated with neural development. For this purpose, we adapted a system to induce neural progenitor cell (NPC) development from mouse embryonic stem cell (ESC) lines deficient for XRCC4 plus p53, a genotype that enhances DNA double-strand break (DSB) persistence to enhance detection. We tested for RDCs by our genome wide DSB identification approach that captures DSBs genome-wide via their ability to join to specific genomic Cas9/sgRNA-generated bait DSBs. In XRCC4/p53-deficient ES cells, we detected 7 RDCs, which were in genes, with two RDCs being robust. In contrast, in NPCs derived from these ES cell lines, we detected 29 RDCs, a large fraction of which were robust and associated with long, transcribed neural genes that were also robust RDC-genes in primary NSPCs. These studies suggest that many RDCs present in NSPCs are developmentally influenced to occur in this cell type and indicate that induced development of NPCs from ES cells provides an approach to rapidly elucidate mechanistic aspects of NPC RDC formation. SIGNIFICANCE STATEMENTWe previously discovered a set of long neural genes susceptible to frequent DNA breaks in primary mouse brain progenitor cells. We termed these genes RDC-genes. RDC-gene breakage during brain development might alter neural gene function and contribute to neurological diseases and brain cancer. To provide an approach to characterize the unknown mechanism of neural RDC-gene breakage, we asked whether RDC-genes appear in neural progenitors differentiated from embryonic stem cells in culture. Indeed, robust RDC-genes appeared in neural progenitors differentiated in culture and many overlapped with robust RDC-genes in primary brain progenitors. These studies indicate that in vitro development of neural progenitors provides a model system for elucidating how RDC-genes are formed.

neuroscience↗