Pearl Bodies as a Potential Source of Secondary Transmission of Papaya Leaf Distortion Mosaic Virus in Carica papaya.

Abstract

Pearl bodies are small, pearl-like structures found on the surfaces of many tropical and subtropical plant species, including Carica papaya L., that serve as a nutritious food source for arthropods, helping plants defend against herbivores. This study investigated the role of pearl bodies in viral accumulation and transmission, focusing on papaya plants infected with papaya leaf distortion mosaic virus (PLDMV), a destructive pathogen threatening papaya production. Viral analysis of pearl bodies from PLDMV-infected plants confirmed the presence of viral particles, genomic RNA, and coat protein, with quantitative real-time RT-PCR showing significant viral RNA accumulation. These findings suggest that pearl bodies act as reservoirs for PLDMV. Infectivity tests demonstrated that ruptured pearl bodies from infected plants effectively transmitted PLDMV to healthy plants via mechanical inoculation. The fragility of stalks and cell surfaces of pearl bodies facilitate their detachment or rupture during mechanical activities, potentially releasing virus-laden contents into the environment. This poses a significant risk of contamination for agricultural tools, equipment, and personnel, contributing to secondary transmission. This study emphasizes the importance of recognizing pearl bodies as an overlooked source of viral spread, highlighting the need for careful handling and targeted management strategies to reduce virus transmission risks in papaya cultivation. This is the first report of pearl bodies' involvement in virus transmission, which provides novel insights into virus epidemiology and disease management in papaya cultivation and other crops with pearl bodies.