Nicola Schmidt s Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Technical University Dresden in the year 2019.
Characterisation of the endogenous phytopararetrovirus beetEPRV3 in the sugar beet genome (Beta vulgaris), a new member of the florendoviruses within the Caulimoviridae family
For the first time, the three endopararetrovirus families within the sugar beet genome were described and analysed focusing on the family beetEPRV3. The element structure turned out to be characteristic for the respective beetEPRV family, pointing to specific evolutionary scenarios. Further, the viral sequences were found to be located within highly AT-rich heterochromatin, which provides an explanation for lacking virulence of beetEPRVs.
Endopararetroviruses (EPRVs) are a widespread component of animal and plant genomes as a result of the integration of the viral DNA. A reactivation can cause devastating diseases, as it is known for tobacco or petunia. Using comprehensive bioinformatic methods, in this work the EPRVs within the sugar beet genome were identified and assigned to the florendoviruses, which is an abundant genus within the Caulimoviridae. The element structure was reconstructed for all three beetEPRV families. Two families (beetEPRV1 and beetEPRV3) show intact copies, whereas the third family (beetEPRV2) is arranged in a more fragmented manner. The family beetEPRV3 was furthermore analysed using molecular biological and cytogenetic methods like Southern hybridisation and fluorescent in situ hybridisation. It turned out that EPRVs belonging to this family accumulate in tight, repetitive and therefore mostly inaccessible DNA regions, allowing them to escape the host’s elimination mechanisms. These findings may help to understand how EPRVs keep their virulence in some hosts over long periods.
Nicola Schmidt conducted this work at the chair of Plant Cell and Molecular Biology in the group of Prof. Dr. Thomas Schmidt.