Cassava begomovirus species diversity changes during plant vegetative cycles

• DOI: 10.3389/fmicb.2023.1163566
• Publication Date: 2023-05-25T04:42:43Z
• Authors: Anna E. Dye; Brenda Muga; Jenniffer Mwangi; J. Steen Hoyer; Vanessa Ly; Yamilex Rosado; William Sharpee; Benard Mware; Mary Wambugu; Paul Labadie; David Deppong; Louis Jackai; Alana Jacobson; George Kennedy; Elijah Ateka; Siobain Duffy; Linda Hanley-Bowdoin; Ignazio Carbone; José Trinidad Asc...
• Keywords: whitefly (Bemisia tabaci); vector transmission; Plant virus; Plant Science; Crop; vegetative (asexual) propagation; Microbiology; cassava; Agricultural and Biological Sciences; plant virus; Virology; Host Plant Selection; Biology; 2. Zero hunger; plants; Cassava (Manihot esculenta); Insect-Plant Interactions in Agricultural Ecosystems; Botany; Life Sciences; food security; Whitefly; QR1-502; Agronomy; 3. Good health; Plant-Parasitic Nematodes in Molecular Plant Pathology; Virus; Geminiviridae; Insect Science; Begomovirus; Viral RNA Silencing and Plant Immunity

Cassava is a root crop important for global food security and the third biggest source of calories on the African continent. Cassava production is threatened by Cassava mosaic disease (CMD), which is caused by a complex of single-stranded DNA viruses (family: Geminiviridae, genus: Begomovirus) that are transmitted by the sweet potato whitefly (Bemisia tabaci). Understanding the dynamics of different cassava mosaic begomovirus (CMB) species through time is important for contextualizing disease trends. Cassava plants with CMD symptoms were sampled in Lake Victoria and coastal regions of Kenya before transfer to a greenhouse setting and regular propagation. The field-collected and greenhouse samples were sequenced using Illumina short-read sequencing and analyzed on the Galaxy platform. In the field-collected samples, African cassava mosaic virus (ACMV), East African cassava mosaic virus (EACMV), East African cassava mosaic Kenya virus (EACMKV), and East African cassava mosaic virus-Uganda variant (EACMV-Ug) were detected in samples from the Lake Victoria region, while EACMV and East African mosaic Zanzibar virus (EACMZV) were found in the coastal region. Many of the field-collected samples had mixed infections of EACMV and another begomovirus. After 3 years of regrowth in the greenhouse, only EACMV-like viruses were detected in all samples. The results suggest that in these samples, EACMV becomes the dominant virus through vegetative propagation in a greenhouse. This differed from whitefly transmission results. Cassava plants were inoculated with ACMV and another EACMV-like virus, East African cassava mosaic Cameroon virus (EACMCV). Only ACMV was transmitted by whiteflies from these plants to recipient plants, as indicated by sequencing reads and copy number data. These results suggest that whitefly transmission and vegetative transmission lead to different outcomes for ACMV and EACMV-like viruses.