SEGS-1 episomes generated during cassava mosaic disease enhance disease severity

• DOI: 10.3389/fpls.2024.1469045
• Publication Date: 2025-01-10T06:13:31Z
• Authors: Evangelista Chiunga; Catherine D. Aimone; Cyprian Rajabu; Mary M. Dallas; Joseph Ndunguru; José T. Ascencio-...; Elijah M. Ateka; Linda Hanley-Bowdoin
• Keywords: Mosaic

Cassava is an important root crop that produced by smallholder farmers across Sub-Saharan Africa. mosaic disease (CMD), which caused a group of cassava begomoviruses (CMBs), one the most devastating diseases cassava. A previous study showed SEGS-1 (sequences enhancing geminivirus symptoms), occur both in genome and as episomes during CMD, can increase CMD severity overcome host resistance. In this report, we examined effects exogenously applied on incidence CMB infection, symptom severity, viral DNA copy number five cultivars ranged from highly susceptible to resistant CMD. These studies revealed effect cultivar dependent. Susceptible developed severe with or without exogenous SEGS-1, while increased carrying CMD2 resistance, conferred single locus, but not CMD1 polygenic. Analysis infected plants absence some, all, form The presence endogenous TME14, cultivar, correlated severity. contrast, TME3, closely related did produce was more resistance than TME14. different capacities TME3 TME14 unlikely due sequence differences around their genomic loci. functional regions were mapped using sequences flanking episome junction, junction itself required for activity. All have genomes potential negatively impact development stable breeding programs.