Biology subjects

Hohenwarter, L.

Publications and source records attributed to Hohenwarter, L..

3 recordsLinked to original sources

bioRxiv2026

Functional RNA Interference in Hymenoscyphus fraxineus: Hairpin RNA-Induced Gene Silencing Of A Polyketide Synthase-like Gene

European ash dieback caused by the invasive ascomycete species Hymenoscyphus fraxineus poses the most prominent danger to common ash trees (Fraxinus excelsior) in Europe. The disease is widely distributed in Europe and currently no efficient management strategy is available. Host-induced gene silencing and exogenous dsRNA applications have shown great potential for controlling fungal diseases in crop plants. In this study, we reported in silico evidence for the presence of a functional RNA interference pathway in Hymenoscyphus fraxineus. Moreover, we showed that the transgenic expression of a double stranded RNA (dsRNA) leads to inhibition of translation of its target polyketide synthase-like gene, a fungal endogene. We explored whether the dsRNA could be introduced exogenously and demonstrated that H. fraxineus can take up externally applied dsRNA molecules. This study highlights the RNA interference mechanism in H. fraxineus and suggests exoRNA applications as a promising approach to control European ash dieback.

molecular biology↗

bioRxiv2022

Induction of promoter methylation and transcriptional gene silencing upon high pressure spraying of 24-nt small RNAs in Nicotiana benthamiana

Exogenous RNA application is a promising transgene-free approach for crop protection and improvement. In almost all applications reported so far, exogenous RNA molecules (double stranded RNAs or small RNAs) are applied to plants in order to trigger degradation of a given mRNA (of plant, pest or pathogen origin), in a process termed post-transcriptional gene silencing (PTGS). However, whether exogenous RNAs can also trigger epigenetic modifications to plants such as RNA-directed DNA methylation (RdDM) and transcriptional gene silencing (TGS) remains largely unaddressed. Here, we provide evidence that high pressure spraying of a 24-nt short interfering RNA (siRNA) designed to target the CaMV 35S promoter that drives the expression of a GFP transgene, resulted in promoter RdDM in N. benthamiana. Moreover, the methylation at the target site spreads both up and downstream neighboring sites. Importantly, GFP expression was reduced in the sprayed leaf tissues. Small RNA sequencing excluded the presence siRNAs mapping to the GFP gene body and documented substantial amount of secondary RNAs in the promoter, suggesting that the GFP silencing was transcriptional rather than post-transcriptional. Our study provides a proof of principle for spray induced epigenetic modification (SPIEM) that could be used in modern crop breeding platforms.

plant biology↗

bioRxiv2018

Efficient reverse breeding by VIGS-mediated transient crossover reduction

F1 heterozygotes are traditionally generated by crossing homozygous parental lines. The opposite is achieved through reverse breeding, in which parental lines are generated from a heterozygote. Reverse breeding can be used to develop new F1 hybrid varieties without having prior access to homozygous breeding lines. For successful reverse breeding, the heterozygotes homologous chromosomes must be divided over two haploid complements, which is achieved by suppression of meiotic crossover (CO) recombination. We here show two innovations that facilitate efficient reverse breeding. Firstly, we demonstrate that downregulation of CO rates can be accomplished using virus-induced gene silencing (VIGS). We obtain transgene-free parental lines for a heterozygote in just two generations. Secondly, we show that incomplete CO suppression opens up several alternative strategies for the preservation of hybrid phenotypes through reverse breeding.

plant biology↗