A shift in Begomovirus coheni populations associated with tomato yellow leaf curl disease infecting tomato cultivars in the Southeastern United States

Authors: KUMAR, MANISH - UNIVERSITY OF GEORGIA; BAG, SUDEEP - UNIVERSITY OF GEORGIA; MCAVOY, THEODORE - UNIVERSITY OF GEORGIA; TORRANCE, TY - UNIVERSITY OF GEORGIA; CLOUD, CALE - UNIVERSITY OF GEORGIA; SIMMONS, ALVIN

Submitted to: Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2025
Publication Date: 3/20/2025
Citation: Kumar, M., Bag, S., Mcavoy, T., Torrance, T., Cloud, C., Simmons, A.M. 2025. A shift in Begomovirus coheni populations associated with tomato yellow leaf curl disease infecting tomato cultivars in the Southeastern United States. Plant Pathology. https://doi.org/10.1111/ppa.14091.
DOI: https://doi.org/10.1111/ppa.14091

Interpretive Summary: The sweetpotato whitefly is a global insect pest that transmits many crop plant viruses including the tomato yellow leaf curl virus. A study was conducted to determine if there are more than one variant of the tomato yellow leaf curl virus in the state of Georgia and the infection of the variant in commercial tomato production. Genetic analyses support a change in the population of the tomato yellow leaf curl virus in Georgia and was found to be widespread in commercial tomato fields. Results from this study will be useful to help scientists to breed tomatoes that are more resistant to whitefly-transmitted viruses.

Technical Abstract: Tomato yellow leaf curl virus (TYLCV) is a major pathogen responsible for tomato yellow leaf curl disease (TYLCD), significantly impacting the growth and productivity of tomato crops. Full-length genome sequences of three TYLCV isolates were generated from commercially grown tomato cultivars in fields in Georgia, USA. Nucleotide sequence identity confirmed the presence of Begomovirus coheni (TYLCV) in the symptomatic samples. A genome map illustrating all open reading frames (ORFs) and their coordinates in conjugation with the Guanine-Cytosine (GC) dinucleotide distribution was generated. The phylogenetic dendrogram analysis of these sequences forms a clade consisting of TYLCV isolates reported from European and Mediterranean countries. Analysis of TYLCV isolates infecting tomatoes in the USA revealed the formations of at least two distinct clades based on their year of occurrence. Agrobacterium-mediated infectivity of partial tandem repeats (infectious clones) of TYLCV-GA isolate expressed severe symptoms on a tomato cultivar after 30 days post-inoculation (dpi). The infectious clones were acquired by whiteflies and were transmitted to tomato cultivars, expressing severe symptoms suggesting its pathogenicity in natural host plants. Genetic variability parameters of TYLCV population (reported from 2007 to 2022), including three full-length TYLCV-GA, showed purifying selection or recent population expansion of tomato-associated TYLCV isolates/variants in the United States. Synonymous and non-synonymous mutations corresponding to the Geminivirus Rep Sequences (GRS) motif, motif III of Rep protein, and WCCH motif of coat protein indicated genetic mutations in the conserved motifs. Our study demonstrated that TYLCV-GA is widespread on the commercial farm scale in field in Georgia and causes severe disease in tomato cultivars. This population shift in begomoviruses associated with TYLCD might lead to the emergence of TYLCV-GA variants in natural conditions.