Managing tomato bacterial wilt through pathogen suppression and host resistance augmentation using microbial peptide

Area of Science:

• Agricultural Science
• Microbiology
• Biotechnology

Background:

• Synthetic pesticides pose health and environmental risks, driving demand for sustainable plant protection.
• Bacterial wilt (BW) caused by Ralstonia solanacearum severely impacts tomato (Solanum lycopersicum) production.
• Antimicrobial peptides (AMPs) are a promising class of natural biocontrol agents.

Purpose of the Study:

• To investigate the efficacy of a biosynthesized AMP from Lactiplantibacillus argentoratensis IT against Ralstonia solanacearum in tomato.
• To evaluate the AMP's direct antimicrobial activity and its role in inducing plant defense mechanisms.
• To assess the impact of AMP application on tomato plant growth and morphology.

Main Methods:

• Foliar application of biosynthesized AMP (PRKGSVAKDVLPDPVYNSKLVTRLINHLMIDGKRG) at 200 ppm.
• Assessment of disease incidence and severity of bacterial wilt in tomato plants.
• Scanning electron microscopy to observe bacterial cell morphology changes.
• Measurement of plant defense enzyme activities and plant growth parameters (length, biomass, root length).

Main Results:

• Foliar AMP application significantly reduced bacterial wilt incidence by 49.3% and severity by 45.8%.
• Scanning electron microscopy confirmed severe morphological damage to Ralstonia solanacearum cells.
• AMP treatment enhanced host resistance, increasing plant length (95.5%), biomass (20.1%), and root length (96.69%).

Conclusions:

• The biosynthesized AMP exhibits dual functionality: direct antimicrobial action against R. solanacearum and induction of tomato plant defense responses.
• This AMP represents a novel, effective, and sustainable biocontrol agent for managing bacterial wilt in Solanum lycopersicum.
• This study is the first to report the foliar application of a biosynthesized microbial peptide for biocontrol of R. solanacearum and promotion of tomato growth.