Symptom Expression, Host Range, and Molecular Identity of Alfalfa Mosaic Virus Infecting Leguminous Crops

Abstract

Symptom expression, host range, and molecular identity of Alfalfa Mosaic Virus (AMV) infecting leguminous crops were investigated to understand disease variability and genetic characteristics across different hosts. Field surveys were conducted in major legume-growing regions, and symptomatic samples exhibiting mosaic, chlorosis, leaf distortion, and stunted growth were collected for analysis. Host range studies were performed through mechanical inoculation on selected leguminous species to evaluate systemic infection and symptom development. Results indicated that AMV exhibited a broad host range within leguminous crops, with variation in symptom severity depending on host genotype and environmental conditions. Molecular identification was carried out using RT-PCR amplification and sequencing of coat protein and genomic RNA segments, confirming the presence of genetically diverse AMV isolates. Phylogenetic analysis revealed clustering of isolates into distinct groups, suggesting evolutionary divergence and possible regional adaptation. Symptom expression varied from mild mosaic patterns to severe systemic chlorosis, indicating differential host–virus interactions. Certain legume hosts showed partial tolerance, with reduced symptom intensity despite successful viral infection. The study highlights the epidemiological significance of AMV in legume production systems and emphasizes the need for accurate molecular diagnostics for early detection. These findings provide valuable insights for breeding virus-resistant legume cultivars and developing integrated disease management strategies to mitigate yield losses caused by Alfalfa Mosaic Virus.