Executive Summary : | Begomoviruses are a group of single stranded DNA viruses that infect many crops. Tomato (Solanum lycopersicum L.) - infecting begomoviruses, are reported from all tomato growing regions of world (Verma and Malathi 2003; ICTV online 2021). More than 70 species of begomoviruses have been reported to infect tomato, this is the largest number of begomovirus infecting to any crop. As a vegetable of high nutritious value, tomato is an important crop cultivated in both temperate and tropical countries and consumed all over the world. Begomovirus that causes a typical leaf curl disease on tomato (Tomato leaf curl disease, ToLCD) is called as Tomato leaf curl virus (ToLCV). In India, till now 14 species of ToLCVs are reported. But in Bihar, where severe incidences of Tomato leaf curl disease (ToLCD) are reported, only one novel species of ToLCV is reported till now (Tomato leaf curl Patna virus- ToLCVPaV, Kumari et. al., 2010). Global expansion of a species of ToLCV (namely Tomato leaf curl New Delhi virus) has been reported recently (Moriones et. al., 2017; Zaidi et. al., 2017). Similarly recent spread of ToLCVPaV to other hosts in different states of India is also being reported (Saeed and Samad, 2016; Shorab, 2016). Presently, plant host range expansion and mixed infections are contributing in shaping ToLCD in a pandemic. However, scientist are putting serious efforts to control begomovirus spread by generating resistant varieties of host, but due to the fast evolving and recombining nature of the genomic component of virus (DNA-A, DNA-B and associated DNA-β), commercial success is still not achieved (Prasanna et. al., 2015; Yan et. al., 2021). In present scenario there is an urgent need of comprehensive study of diversifying spread of ToLCVs that are infecting tomato in districts of Bihar. Begomoviruses genomic sequences have great recombining ability (Prasanna et. al., 2007; Kumari et., al., 2011). Every new molecule of virus isolated and characterized from nature may reveal some noble variations in the mechanism of interactions with host. This is the reason behind the complexity in generating a full proof strategy against this virus which will not only control the disease but also restrict its dynamic evolution by controlling the infections. This project will be focussed on study of ToLCVs in different vegetable growing districts of Bihar, DNA isolation and PCR confirmation of infected field sample, amplification of viral genome, cloning of viral genome and construction of infectious clone to characterize the virus in glass house condition, sequencing of cloned viral genome and analysis of sequence to reveal its evolutionary tendencies. Current approach of resistant gene pyramiding to generate broad spectrum resistance against tomato-infecting begomoviruses, demands up to date data of virus genome prevalent in field condition, to screen and confirm the newly developed resistant crop variety. This knowledge will be generated through this project. |