Epidemiological Study of Begomoviruses from South American Region

Abstract

Plant viruses cause a devastating loss in economically important crops throughout the world. Begomovirus (family Geminiviridae) are circular, single-stranded DNA viruses, transmitted by a single species of Bemisia tabaci (whitefly) in a persistent circulative manner. Begomovirus are the most destructive and diverse group of plant DNA viruses that affect a wide variety of dicotyledonous plants including crops, vegetables, ornamental plants, and weeds. Weeds and ornamental plants serve as a source of inoculum, alternate hosts, and recombination sites for the emergence of new virus species/strains. The present study is aimed at determining the epidemiological analyses of Begomovirus from the South American region. The complete length nucleotide sequences of 63 Begomoviruses present in South American regions were retrieved from NCBI. The Begomovirus species were verified through the species demarcation tool (SDT), using a 91% cut-off value as recommended by the International Committee for Taxonomy of Viruses (ICTV). The phylogenetic analysis was performed using Mega X Software, and graphs/maps were generated through MS Excel. A total of sixty-three (63) Begomovirus species (1074 isolates) have been found in the South American region which are infecting fifty-eight (58) plant species. the plants majorly infected are Solanum lycopersicum (26 virus species and 432 isolates), Phaseolus vulgaris (7 virus species and 127 isolates), Macroptilium lathyroides (4 virus species and 52 isolates) and Phaseolus lunatus (7 species and 70 isolates), Ipomoea batatas (3 virus species and 53 isolates), Euphorbia heterophylla (2 virus species and 57 isolates), Leonurus sibiricus (4 virus species and 51 isolates) and Capsicum annuum (8 virus species and 26 isolates). Tomato severe rugose virus has dominated in the region (with 234 isolates) followed by Bean golden mosaic virus which has 154 isolates. Other viruses are Euphorbia yellow mosaic virus (62 isolates), Sweet potato leaf curl virus (52 isolates), Sida yellow mosaic virus (44 isolates), Sida micrantha mosaic virus (34 isolates) and Blainvillea yellow spot virus (28 isolates). 924 isolates of 33 virus species have been found in Brazil