Research Projects

Horizontal gene transfer, particularly in the form of DNA/RNA, has significantly influenced the adaptive evolution of organisms. A study on Apple scar skin viroid (ASSVd) reported the first-time horizontal transfer of naked RNAs from plants to whiteflies. Later, studies have reported the horizontal transfer of plant miRNA, sRNAs, and lncRNAs. Cross-kingdom transmission of artificial sRNAs, such as spray induced gene silencing (SIGS), offers an innovative tool for pathogen/pest management. However, factors limit SIGS RNAi efficiency in plant phloem feeders like whiteflies. Therefore, developing mechanisms for sprayed dsRNA to enter and traffic through phloem are essential for generating efficient SIGS in phloem feeders. Understanding the mechanism of cross-kingdom trafficking in the Plant-Viroid-Whitefly system might benefit in designing effective strategies against whiteflies. Recent reports highlight the role of Extracellular Vesicles (EVs) and RNA Binding Proteins (RBPs) in delivering sRNAs into fungal pathogens to suppress expression of virulence-related genes. Profiling of EVs RNA showed they are enriched in circular RNAs and lncRNAs, apart from sRNAs. EVs are also present in phloem and their role in systemic RNA transport is postulated. In this proposal, using cucumber plants as hosts, viroid as RNA pathogen, and whiteflies as insect vectors, the aim is to decipher the mechanism of cross-kingdom trafficking and validate the role of EVs and RBPs in this process. Finally, applying our understanding of cross-kingdom transmission to engineer viroids as cross-kingdom delivery vehicles for robust RNAi against whiteflies.