Browsing by Person "Born, Ute"

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Degradation of hop latent viroid during anaerobic digestion of infected hop harvest residues
(2021) Hagemann, Michael Helmut; Born, Ute; Sprich, Elke; Seigner, Luitgardis; Oechsner, Hans; Hülsemann, Benedikt; Steinbrenner, Jörg; Winterhagen, Patrick; Lehmair, Erich
The citrus bark cracking viroid (CBCVd) was identified as causal agent for a severe stunting disease in hops. Viroids are highly stable parasitic RNAs, which can be easily transmitted by agricultural practices. Since CBCVd has recently been detected in two European countries a growing concern is that this pathogen will further spread and thereby threaten the European hop production. Biogas fermentation is used to sanitize hop harvest residues infected with pathogenic fungi. Consequently, the aim of this study was to test if biogas fermentation can contribute to viroid degradation at mesophilic (40 °C) and thermophilic (50 °C) conditions. Therefore, a duplex reverse transcription real-time PCR analysis was developed for CBCVd and HLVd detection in biogas fermentation residues. The non-pathogenic hop latent viroid (HLVd) was used as viroid model for the pathogenic CBCVd. The fermentation trials showed that HLVd was significantly degraded after 30 days at mesophilic or after 5 days at thermophilic conditions, respectively. However, sequencing revealed that HLVd was not fully degraded even after 90 days. The incubation of hop harvest residues at different temperatures between 20 and 70 °C showed that 70 °C led to a significant HLVd degradation after 1 day. In conclusion, we suggest combining 70 °C pretreatment and thermophilic fermentation for efficient viroid decontamination.
Prevalence, genetic diversity, and molecular detection of the apple hammerhead viroid in Germany
(2025) Zikeli, Kerstin; Berwarth, Constanze; Born, Ute; Leible, Thomas; Jelkmann, Wilhelm; Hagemann, Michael Helmut
Introduction: Apple hammerhead viroid (AHVd) is an emerging plant pathogen infecting apple orchards worldwide. Its genetic variability and geographical distribution remain poorly understood, limiting effective diagnostics and management strategies. Methods: In this study, 192 samples from German apple orchards were analyzed using reverse transcription (RT) and real-time PCR, one-step RT real-time PCR, and Sanger sequencing. Next-generation sequencing (NGS) was employed on pooled RNA extracts to explore genetic diversity. Phylogenetic relationships were inferred using maximum likelihood methods, and viroid-derived small RNAs (vd-sRNAs) were identified from small RNA sequencing data. Results and discussion: AHVd was detected in 78% of samples, with prevalence varying by region: southern (82%), eastern (90%), northern (72%), and western (70%) states of Germany. Phylogenetic analysis revealed distinct clusters linked to geographical origins, indicating isolated evolutionary pathways. NGS analysis uncovered 39% inter-sample variability and 169 polymorphic positions, while Sanger sequencing of RT real-time PCR products derived from the same samples showed only 3% variability, reflecting dominant quasispecies populations. Small RNA analysis mapped 128,388 reads to the AHVd genome, identifying hotspots within and outside the rod-like structure, suggesting structural and regulatory functions of vd-sRNAs. These findings underline AHVd’s genetic diversity. The complex relationship between AHVd genetic variability and symptom expression necessitates the development of highly sensitive diagnostic tools and adaptive management strategies to effectively monitor and control its spread in apple production.