Biology subjects

Mathiopoulos, K.

Publications and source records attributed to Mathiopoulos, K..

5 recordsLinked to original sources

bioRxiv2025

Genome assembly of five Tephritid species for the enhancement of the Sterile Insect Technique

Tephritidae insect pests account for extensive crop damage and yield losses globally. Modern, sustainable pest management approaches are species-specific and, therefore, high-quality genome assemblies are required for their application. Here, we present chromosome-level assemblies for five members of the Tephritidae family: Anastrepha fraterculus, Anastrepha ludens, Bactrocera dorsalis, Bactrocera zonata and Zeugodacus cucurbitae. The assemblies used long read sequencing polished with short read sequencing and scaffolded using Hi-C (chromatin conformation capture) sequencing. Prior to scaffolding the assembly deduplication was performed to separate a primary assembly and an alternate assembly, and each was then scaffolded independently. The scaffolded assemblies reached N50 length in the range of 60Mb to 120Mb. The scaffolded assemblies were verified with BUSCO and completeness was in the range 97% to 98.5% and had very low duplicated, fragmented and missing orthologs.

ecology↗

bioRxiv2025

CRISPR/Cas9-mediated mutagenesis of the white-eye gene in the tephritid pest Bactrocera zonata

Bactrocera zonata is a highly invasive agricultural pest that causes extensive damage to fruit crops. The Sterile Insect Technique (SIT), a species-specific and environmentally friendly pest control method, depends on the availability of Genetic Sexing Strains (GSSs) to enable efficient mass production of males for sterile release. However, no GSS currently exists for B. zonata limiting SIT applications targeting this important invasive pest. Here, we report two key advancements toward GSS development in this species. First, we present a high-quality, chromosome-level genome assembly from male B. zonata, identifying two scaffolds derived from the Y chromosome, which represent potential targets for future male-specific genetic engineering. Second, we demonstrate the feasibility of CRISPR/Cas9 genome editing in B. zonata by generating stable, homozygous white-eye mutants through targeted disruption of the conserved white-eye gene. This visible, recessive phenotype serves as a proof-of-concept for developing selectable markers in this species. Together, these results provide foundational genomic and genetic tools to support the development of GSSs in B. zonata, advancing the potential for sustainable, genetics-based pest control strategies.

bioengineering↗

bioRxiv2022

Improved Nanopore full-length cDNA sequencing by PCR-suppression

Full-length transcript sequencing remains a main goal of RNA sequencing. However, even the application of long-read sequencing technologies such as Oxford Nanopore Technologies still fail to yield full-length transcript sequencing for a significant portion of sequenced reads. Since these technologies can sequence reads that are far longer than the longest known processed transcripts, the lack of efficiency to obtain full-length transcripts from good quality RNAs stems from library preparation inefficiency rather than the presence of degraded RNA molecules. It has previously been shown that addition of inverted terminal repeats in cDNA during reverse transcription followed by single-primer PCR creates a PCR suppression effect that prevents amplification of short molecules thus enriching the library for longer transcripts. We adapted this method for Nanopore cDNA library preparation and show that not only is PCR efficiency increased but gene body coverage is dramatically improved. The results show that implementation of this simple strategy will result in better quality full-length RNA sequencing data and make full-length transcript sequencing possible for most of sequenced reads. Contribution to the fieldLong-read RNA sequencing aims to sequence expressed transcripts in their entirety. However, this has remained a challenge, mainly due to inherent inefficiencies in cDNA library preparation. Herein, we provide a new Nanopore cDNA library preparation protocol, termed Panhandle, that improves the efficiency of cDNA PCR with yields 2 - 8 times the yields obtained with ordinary PCR. This is key, as this should in turn reflect in the possibility of lowering the number of PCR cycles needed to obtain ample sequencing material, which in turn could reduce PCR biases, PCR artifacts, turnaround time, reagents, and could increase general quality of the library. Further, transcripts generated using the Panhandle method show better gene body coverage and more accurate transcription start site mapping than regular methods. This represents an important step towards full-length cDNA sequencing by Nanopore.

genomics↗

bioRxiv2022

A species-specific lncRNA modulates the reproductive ability of the Asian tiger mosquito

Long non-coding RNA (lncRNA) research has emerged as an independent scientific field in recent years. Despite their association with critical cellular and metabolic processes in plenty of organisms, lncRNAs are still a largely unexplored area in mosquito research. We propose that they could serve as exceptional tools for pest management due to unique features they possess. These include low inter-species sequence conservation and high tissue specificity. In the present study, we investigated the role of ovary-specific lncRNAs in the reproductive ability of the Asian tiger mosquito, Aedes albopictus. Through the analysis of transcriptomic data, we identified several lncRNAs that were differentially expressed upon blood feeding; we called these genes Norma (NOn-coding RNA in Mosquito ovAries). We observed that silencing some of these Normas resulted in significant impact on mosquito fecundity and fertility. We further focused on Norma3 whose silencing resulted in 43% oviposition reduction and 53% hatching reduction of the laid eggs, compared to anti-GFP controls. Moreover, a significant downregulation of a neighboring ([~]100 Kb) mucins cluster was observed in smaller anti-Norma3 ovaries, indicating a potential mechanism of in-cis regulation between Norma3 and the mucins. Our work constitutes the first experimental proof-of-evidence connecting lncRNAs with mosquito reproduction and opens a novel path for pest management.

molecular biology↗

bioRxiv2018

Decoding the reproductive system of the olive fruit fly, Bactrocera oleae

A great deal of behavioral and molecular interactions between male and female insects takes place during insect reproduction. Here, we comprehensively analyze the reproductive system of the olive fruit fly. Specifically, transcriptomic and genomic analysis of the reproductive tissues from virgin and once mated insects were performed. Genes encoding proteins implicated in immune response, mucins, antigen 5 proteins, proteases inhibitors and proteins with putative secretory activity were identified. Comparison of the transcriptomes between virgin and mated insects resulted in the identification of genes that are up- or down-regulated after mating. In testes 106 genes were up-regulated and 344 genes were down-regulated, whereas in male accessory glands with ejaculatory bulb 1,607 genes were up-regulated and 384 genes were down-regulated in mated male insects. Respectively, in mated females 1,705 genes were up-regulated and 120 genes were down-regulated in mated insects. To get a deeper insight, the expression profiles of selected genes throughout sexual maturation for the male tissues and throughout different time points after mating for the female reproductive tissues were determined. Identification of genes that take part in the mating procedure not only gives an insight in the biology of the insects, but it could also help the identification of new target genes in order to disturb the reproductive success of the olive fly and thus develop alternative pest control method.

molecular biology↗