Pathogenicity and Host Range of Pseudomonas syringae pv. tomato Isolates Collected from Infected Tomato Fields

Abstract

Bacterial speck disease caused by Pseudomonas syringae pv. tomato is a major constraint in tomato production, leading to significant reductions in crop quality and marketable yield. The present study investigated the pathogenicity and host range of P. syringae pv. tomato isolates collected from infected tomato fields to understand their virulence characteristics and potential host adaptability. Diseased tomato samples exhibiting typical speck symptoms were collected from different production areas, and bacterial isolates were obtained using standard isolation and purification techniques. Morphological, biochemical, and molecular analyses were conducted for pathogen identification and confirmation. Pathogenicity tests were performed under controlled conditions through artificial inoculation of healthy tomato plants, and disease severity was assessed based on lesion development, chlorosis, and necrotic symptoms. Considerable variation in aggressiveness was observed among the tested isolates, with some strains inducing severe symptoms and rapid disease progression. Host range studies were conducted using selected solanaceous and non-solanaceous plant species to evaluate susceptibility patterns. The results demonstrated that several isolates were capable of infecting multiple host plants with varying levels of symptom expression, indicating broad host adaptability and potential epidemiological significance. Differences in virulence among isolates suggested the existence of pathogenic variability within the bacterial population. The integration of pathogenicity assessment and host range analysis provided valuable insights into the biology and spread of P. syringae pv. tomato. The findings contribute to improved disease diagnosis and support the development of effective integrated disease management strategies for sustainable tomato production.