Differential pathogenicity among Tomato leaf curl Gujarat virus isolates from India

Area of Science:

• Plant Pathology
• Virology
• Molecular Biology

Background:

• Tomato leaf curl disease (ToLCD) is a major threat to tomato production in India.
• Tomato leaf curl Gujarat virus (ToLCGV) is a key pathogen responsible for ToLCD.
• Previous studies have documented ToLCGV isolates causing severe ToLCD.

Purpose of the Study:

• To identify and characterize ToLCGV isolates from infected tomato plants in Dhanbad and Ramgarh, India.
• To investigate the roles of DNA A, DNA B, and betasatellite components in ToLCGV pathogenicity.
• To determine the factors contributing to differential virulence among ToLCGV isolates.

Main Methods:

• Polymerase Chain Reaction (PCR) was used to confirm begomovirus presence and identify ToLCGV isolates.
• Inoculation studies were performed with DNA A, DNA B, and Tomato yellow leaf curl Thailand betasatellite (TYLCTHB) to assess their individual and combined effects.
• Virus DNA accumulation was quantified to understand replication dynamics.

Main Results:

• ToLCGV isolates were identified in Dhanbad and Ramgarh, associated with TYLCTHB betasatellite.
• Both isolates' DNA A could infect tomato plants, but virulence differed.
• Co-inoculation with TYLCTHB reduced incubation period but did not alter helper virus DNA accumulation.
• The Ramgarh isolate was identified as a mild strain of ToLCGV, with DNA B influencing DNA A accumulation differently in Dhanbad and Ramgarh isolates.

Conclusions:

• Differential pathogenesis in ToLCGV isolates is primarily governed by the helper component, not the betasatellite.
• The Ramgarh isolate represents a mild strain of ToLCGV, contributing to varied disease severity.
• Understanding these viral components is crucial for developing effective ToLCD management strategies.