SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

Cyprian A Rajabu; Mary M Dallas; Evangelista Chiunga; Leandro De León; Elijah M Ateka; Fred Tairo; Joseph Ndunguru; Jose T Ascencio-Ibanez; Linda Hanley-Bowdoin

doi:10.3389/fpls.2023.1250105

SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

Front Plant Sci. 2023 Oct 17:14:1250105. doi: 10.3389/fpls.2023.1250105. eCollection 2023.

Authors

Affiliations

¹ Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States.
² Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
³ Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States.
⁴ Tanzania Agricultural Research Institute-Mikocheni, Dar Es Salaam, Tanzania.

Abstract

Cassava is a major crop in Sub-Saharan Africa, where it is grown primarily by smallholder farmers. Cassava production is constrained by Cassava mosaic disease (CMD), which is caused by a complex of cassava mosaic begomoviruses (CMBs). A previous study showed that SEGS-1 (sequences enhancing geminivirus symptoms), which occurs in the cassava genome and as episomes during viral infection, enhances CMD symptoms and breaks resistance in cassava. We report here that SEGS-1 also increases viral disease severity in Arabidopsis thaliana plants that are co-inoculated with African cassava mosaic virus (ACMV) and SEGS-1 sequences. Viral disease was also enhanced in Arabidopsis plants carrying a SEGS-1 transgene when inoculated with ACMV alone. Unlike cassava, no SEGS-1 episomal DNA was detected in the transgenic Arabidopsis plants during ACMV infection. Studies using Nicotiana tabacum suspension cells showed that co-transfection of SEGS-1 sequences with an ACMV replicon increases viral DNA accumulation in the absence of viral movement. Together, these results demonstrated that SEGS-1 can function in a heterologous host to increase disease severity. Moreover, SEGS-1 is active in a host genomic context, indicating that SEGS-1 episomes are not required for disease enhancement.

Keywords: ACMV; Arabidopsis thaliana; SEGS-1; begomovirus; cassava.

Grants and funding

This study was funded by the Bill & Melinda Gates Foundation Grant #51466 to JN and Grant # OPP1149990 to LHB, JN and JAI. Under the grant conditions of the Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the authors’ accepted manuscript version that might arise from this submission.