Genomics insight on passion fruit viral disease complexity

Area of Science:

• Plant Virology
• Genomics
• Phylogenetics

Background:

• Passion fruit viral diseases significantly impact Kenya's passion fruit industry.
• Woodiness disease symptoms, including fruit hardening and leaf distortion, are prevalent.
• This is the first comprehensive study of passion fruit viral diseases in Kenya.

Purpose of the Study:

• To conduct comprehensive virus surveys in Kenyan passion fruit-growing regions.
• To characterize the genomes of identified viruses and understand their genetic diversity.
• To propose neutral nomenclature for identified viruses and inform management strategies.

Main Methods:

• Field surveys across major passion fruit-growing counties in Kenya.
• Genomic sequencing of viral isolates, including complete genome assembly.
• Phylogenetic and recombination analyses to determine viral relationships and introductions.
• Symptom correlation studies to understand coinfection impacts.

Main Results:

• Identified Ugandan passiflora virus (UPV) and East Asian passiflora distortion virus (EAPDV) as major pathogens.
• Sequenced 23 complete UPV genomes and 2 EAPDV genomes from Kenya.
• UPV strains showed 99% nucleotide identity to Ugandan isolates; EAPDV showed 66% identity to UPV.
• Detected distinct phylogenetic lineages suggesting multiple introductions and potential synergistic coinfections.

Conclusions:

• Proposed renaming EAPDV to Passiflora distortion virus (PDV) and UPV to Passiflora virus (PV).
• Highlighted the role of coinfections in exacerbating disease severity.
• Recommended stringent management, enhanced surveillance, and improved nursery certification to protect the industry.