Characterization of cucumber mosaic virus (CMV) subgroup IB infecting chilli in Tamil Nadu, India

Abstract

CMV (cucumber mosaic virus) is the most primitive virus infecting chilli (Capsicum annuum. L). The mosaic incidence with leaf filiformity, mosaic mottling and stunted growth was observed in major chilli growing regions of Tamil Nadu. CMV sap was inoculated on chilli, cowpea, bitter gourd, bottle gourd, ridge gourd, banana, cucumber, Nicotiana and Chenopodium plants. Host range studies revealed that CMV produced localized infection on Nicotiana and systemic symptoms on most of the test plants. The occurrence of CMV was confirmed through DAC-ELISA and RT-PCR analysis. Host plant samples tested with DAC-ELISA showed strong reaction with 1.7 optical density. For molecular characterization, total RNA isolated from infected plants used in RT-PCR with CMV specific primers. The specific amplicons were cloned and sequenced. The complete genome sequencing depicts CMV-RNA1 consist of 3339 nucleotides (nt), RNA2 and RNA3 with 3052nt and 2027nt respectively. Phylogenetic and nucleotide sequence analysis showed TN CMV isolates closely associated with subgroup IB rather than subgroup IA and II. Comparative sequence analysis indicates replicase protein to be more variable among five genes. CP sequence analysis showed 97-98 per cent identity with subgroup IB strains, 92-93 per cent identity with subgroup IA strains and 81-82 per cent identity with subgroup II strains. CMV-RNA3 was predicted to have recombination with Indian black pepper isolate (KU947031) between 165-505nt and Egyptian tomato isolate (KX014666) between 165-506nt positions.

Co-existence of chlorosis inducing strain of Cucumber mosaic virus with tospoviruses on hot pepper (Capsicum annuum) in India

“…Tospoviruses (CaCV and GBNV) infected chilli plants showed concentric rings on mature leaves and chlorotic spots on younger leaves 12 . Indeed, CMV infected chilli plants showed mosaic mottling, puckering, shoe string or filiformity and stunted growth 26 , 27 . Based on symptomology, symptomatic leaf samples of mosaic mottling along with concentric chlorotic ring spots and mosaic with veinal necrosis were suspected for mixed infection.…”

“…In general, frequent reassortment and recombination occurs in segmented viruses over monopartite viruses 40 . Amicably, CMV undergoes prompt of genetic changes through reasssortment and recombination 27 , 41 , 42 . Thus, evolutionary mechanism is a characteristic attribution of multipartite viruses which plays significant role in emergence and interspecies transmission of viruses 43 .…”

Arabidopsis Tetraspanins Facilitate Virus Infection via Membrane-Recognition GCCK/RP Motif and Cysteine Residues

“…CMV-infected TET leaves were collected for quantitative RT-PCR analysis of CMV Coat Protein (CP) gene abundance after 5 days of infection. The primers were listed in Supplementary Table 1 (Vinodhini et al, 2020).…”