A Comprehensive Review of Chilli Leaf Curl Viral Disease: Molecular Biology, Epidemiology, Diagnostic Advances, and Integrated Management Strategies

Abstract

Chilli leaf curl disease (ChiLCD), caused by Chilli leaf curl virus (ChiLCV), is one of the most devastating viral diseases affecting chilli (Capsicum annuum L.) production in the Indian subcontinent and other tropical and subtropical regions. The disease causes severe yield losses ranging from 30% to nearly 100%, particularly when infection occurs at early crop growth stages, and under epidemic conditions, losses may result in complete failure of the crop. Such severe yield reduction makes ChiLCD a major constraint to sustainable chilli production. ChiLCV is a monopartite begomovirus belonging to the family Geminiviridae, characterized by a circular single-stranded DNA genome encapsidated in distinct geminate particles and persistently transmitted by the whitefly Bemisia tabaci. The viral genome contains overlapping virion-sense and complementary-sense open reading frames that regulates replication, encapsidation, intracellular movement, transcriptional activation, and symptom development. Recent molecular characterization studies have revealed extensive genetic variability among ChiLCV isolates driven by mutation, recombination, and satellite exchange, resulting in the emergence of novel strains capable of expanding over a wide host range, and causing severe epidemics. Phylogenetic and recombination analyses consistently place ChiLCV within the Old World begomovirus clade, highlighting the dynamic evolution of virus–satellite complexes. Advances in molecular diagnostics, such as rolling circle amplification and PCR-based detection, have facilitated rapid identification of viral and satellite components, enabling epidemiological surveillance and resistance breeding programmes. Despite these advances durable management of ChiLCD remains challenging due to the rapid evolution of virus–satellite complexes and the scarcity of stable resistance sources in cultivated chilli. This review emphasizes the urgent need to integrate molecular findings into resistance breeding strategies. Approaches such as marker-assisted selection, RNA interference-based resistance, and CRISPR/Cas-mediated genome editing offer promising avenues for developing long-term solutions. Overall, the review highlights the necessity of an integrated, region-specific, and sustainable disease management strategy that combines host resistance, vector management, and appropriate agronomic practiAces to mitigate the growing threat of ChiLCV and ensure stable chilli production. A comprehensive understanding of the virus, its transmission, and host–vector interactions is essential for resistance breeding and developing effective integrated disease management strategies in chilli cultivation.