Weeds as reservoirs for viruses infecting brinjal in its ecosystem.
Brinjal is the most important vegetable crop cultivated in both tropical and sub-tropical regions due to its high adaptability and the prevailing demand for edible purpose. Brinjal crop expressing viral disease like symptoms viz., mosaic, severe mosaic, vein banding, blistering, stunting were collected. The weed plants in brinjal ecosystem viz., Euphorbia spp. Parthenium hysterophorus, Trianthema portulacastrum, Tridax procumbens and Eclipta prostrata were observed with similar symptoms and these symptoms were also collected. The preliminary detection of viruses was carried for Cucumber mosaic virus (CMV) and Tomato leaf curl New Delhi virus (ToLCNDV) antisera resulted in positive reaction for CMV and ToLCNDV infection in Euphorbia spp. and Parthenium hysterophorus confirmed the infection of CMV and ToLCNDV on these weed plants. The molecular characterization of CMV and ToLNDV was done and positive amplicon covering coat protein regions of both the viruses were cloned and sequenced. Sequences revealed 98% identity of CMV between the weed species and 97% homology with other vegetable CMV isolates of India. 99% of identity was observed between TN isolates of ToLCNDV and 98% identity with other ToLCNDV Indian isolates. Upon phylogenetic analysis the CMV weed host isolates clustered in single clade, separated from CMV brinjal isolate, while all the three isolates of ToLCNDV claded in single clade. The results exemplified that Euphorbia spp. and Parthenium hysterophorus act as reservoirs of CMV and ToLCNDV in the brinjal ecosystem during cropping and off-season of the crop in Tamil Nadu.