Executive Summary : | Tomato is a rich source of a significant amount of nutrients including vitamins, minerals and antioxidants, which are essential for human health. In India, Tomato Leaf Curl New Delhi virus (ToLCNDV) causes up to 100% yield loss in tomato, depending on the stage of infection. Tomato leaf curl disease (TLCD) symptoms consist of plant stunt, flower abortion, leaf curling (upward), and yellowing of leaves. Though breeding has been utilized to protect plants from viral infection, viruses' rapid rate of evolution breaks the resistance barriers in cultivated tomato lines. Thus, there is a need to identify other mechanisms that can provide tolerance to plants against viral infections. In plants, microRNAs (miRNAs) are known to be involved in several biotic and abiotic crosstalk including plant developmental pathways. Recently, miR159-Myb33 module was found to activate Sw5a, a resistance gene that recognizes viral AC4 protein of ToLCNDV to trigger hypersensitive response, thereby restricting the virus spread (Sharma et al., 2021). However, transcriptional regulation of this miRNA is not experimentally established yet. Additionally, recent studies have identified that primary miRNAs (pri-miRNAs) may encode for small peptides, miRNA-encoded peptides (miPEPs) with regulatory roles in plant development. These miPep significantly enhance the transcription of corresponding MIRNA genes, thus, enhancing the level of its associated miRNA. However, the role of these peptides during viral infection in plants is still unknown. Therefore, this project aims to identify the key factors regulating the transcription of miR159 during virus infection. Simultaneously, it also aims to identify miPEPs that are involved during ToLCNDV infection in plants. As the miPEPs are known to be absorbed through roots of plants, their direct application to susceptible plants might prove to be an efficient tool in providing better protection to plants from viral infection, thereby, improving their productivity. Overall, this study will expand our knowledge to the regulatory cascade upstream to miRNAs to fine-tune transitions. |