Assessing sequence diversity of Groundnut rosette disease agents and the distribution of Groundnut rosette assistor virus in major groundnut-producing regions of Ghana

Abstract

The incidence of Groundnut rosette assistor virus (GRAV) in farmers’ fields and sequence diversity of groundnut rosette disease (GRD) agents were assessed in the three northern groundnut production regions of Ghana. GRAV incidence was high (69.5 to 75.0%) but not significantly different between the regions. Nucleotide sequencing of GRAV coat protein (CP) gene revealed 99–100% identity among the Ghanaian isolates and 97–100% similarity to GRAV sequences from Nigeria and Malawi for both nucleotide and predicted amino acids. Nucleotide sequence identities of partial ORF3 and 4 of Groundnut rosette virus (GRV) among the Ghanaian isolates were more variable (89–100%). Ghanaian GRV isolates were more closely related in nucleotide sequence identity to Nigerian isolates (95–98%) than Malawian isolates (88–90%). Similarly, nucleotide identity within Ghanaian GRV-sat RNA’s were close (94–100%), but distinct from Nigerian (82–87%) and Malawian (82–86%) GRV-sat RNAs. Ghanaian isolates of all three agents of GRD showed no obvious isolate diversity patterns based on the regions from where they were collected. We present the first report on the distribution and genetic diversity of GRD agents in Ghana.