ABSTRACT Cowpea ( Vigna unguiculata ) is an important vegetable crop in Trinidad and Tobago as well as the entire Caribbean region. Recently, farmers have reported considerable reduction in crop yield due to diseases, particularly those suspected to be caused by viruses. There were very few reports of cowpea viruses from the Caribbean region, which necessitated the need to look into the emerging viral pathogens that can cause significant crop losses. PCR and nucleic acid sequencing‐based techniques were employed to detect viruses from cowpea plant samples from the farmers' fields in Trinidad. The prevalence of cowpea mosaic virus (CPMV) and potato yellow mosaic virus (PYMV) was detected and characterised through sequencing of the genomes. Whole‐genome sequencing using primer walking revealed that the CPMV‐TnT isolate comprised two RNA segments of 5889 nt (RNA‐1) and 3481 nt (RNA‐2), showing notable divergence in start and stop positions compared to reference genomes. The PYMV‐TnT genome consisted of DNA‐A (2,593 bp) and DNA‐B (2,547 bp), with high similarity to regional isolates and evidence of recombination events, suggesting ongoing genetic diversification within established Caribbean lineages. Phylogenetic analysis confirmed both viruses clustered with Caribbean and South American relatives, though the CPMV RNA‐2 and PYMV DNA‐B sequences displayed distinct branching patterns. Furthermore, absolute qPCR analysis revealed a progressive increase in viral titre throughout the stages of plant development for CPMV and PYMV. The study provides genome‐level characterisation of CPMV and PYMV isolates infecting cowpea in Trinidad, offering updated molecular epidemiological insight into viruses previously reported in the region and thus highlights the need for strategic management and continuous viral surveillance in crops.
Grant et al. (Sun,) studied this question.