Investigating the role of the chromatin regulator LHP1 in defense against geminiviruses and its interplay with the geminivirus-encoded C3 protein

• Applicant: Dr. Zhihao Jiang
• Subject Area: Plant Breeding and Plant Pathology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 511563636

Animals and plants have evolved multi-layered signaling pathways for perceiving and defending against pathogens, including epigenetic regulation. Geminiviruses have emerged as devastating pathogens causing huge losses in crops worldwide. Geminiviruses replicate their circular single stranded (ss) DNA genomes in the nuclei of plant cells through double stranded (ds) DNA intermediates that are wrapped around histones, forming minichromosomes. The geminiviral chromatin is subjected to epigenetic modifications, which have been implicated in the regulation of viral pathogenesis. However, our understanding of the plant-geminivirus epigenetic battlefield is still limited.The host laboratory identified the LIKE HETEROCHROMATIN PROTEIN 1 (LHP1) protein, a Polycomb protein binding H3K27me3 with a function in transcriptional repression, as a direct interactor of the geminivirus Tomato yellow leaf curl virus (TYLCV) C3 protein. C3 is an enhancer of viral replication with a yet-to-be-described essential role for the infection. Further experiments have found that LHP1 plays an anti-geminiviral role in tomato and N. benthamiana. Strikingly, transcriptional analysis showed that C3 largely changes the transcriptional landscape of the host in the context of the virus infection. In this proposal, by using a multidisciplinary approach combining cell biology, molecular biology, protein biochemistry, and genetics, I will focus on uncovering the molecular bases of the anti-geminiviral role of LHP1 and analyzing the impact of the LHP1-C3 interaction on the cell status and the viral infection. This project will expand our understanding of the epigenetic changes underlying the outcome of geminivirus-plant interactions, and will provide insight into the role of LHP1 in the ongoing arms race between plants and viruses.

• DFG Programme: WBP Position