Streptomyces-based biocontrol elicitor for crop disease resistance

Overview

This research proposes a novel biocontrol treatment based on Streptomyces bacteria that protect crops by inducing plant immune responses rather than relying exclusively on antifungal compound production. The technology addresses significant agricultural challenges posed by fungal phytopathogens such as Macrophomina phaseolina and Diaporthe aspalathi, which affect soybean and other crops. By identifying and characterizing bacterial elicitors that trigger plant defense priming, this approach offers a sustainable alternative to traditional chemical fungicides.

The innovation lies in discovering that non-antifungal producing Streptomyces strains also provide effective biocontrol, suggesting that immune system activation plays a key protective role. This dual mechanism, combining direct antifungal activity with induced plant resistance, represents a comprehensive strategy for crop disease management.

Technical specifications

Key features and applications:

• Polyene-producing Streptomyces strains with demonstrated biocontrol activity against soybean pathogens
• Defense-priming mechanism that converts susceptible plant genotypes into resistant ones
• Broad-spectrum protection against multiple phytopathogens including M. phaseolina and D. aspalathi
• Plant fitness promotion through elicitor-induced priming effects
• Sustainable biocontrol reducing dependence on chemical fungicides

Validation approach:

The elicitor identification process involves testing culture supernatants, bacterial pellets, cell extracts, and protease- and heat-treated fractions against target pathogens. Active fractions will be purified through size exclusion chromatography, ion-exchange, or HPLC, with final molecule identification via LC-MS.

Target crops and pathogens:

• Soybean protection against charcoal rot (M. phaseolina)
• Soybean protection against stem canker (D. aspalathi)
• Potential extension to rice and vegetable crops

Technology readiness level

The technology is currently at an advanced research stage with demonstrated biocontrol efficacy in planta. Initial validation has shown significant reduction in plant mortality when Streptomyces inoculation is physically and temporally separated from pathogen challenge, confirming the induced resistance mechanism. The next phase focuses on identifying and characterizing the specific bacterial elicitor molecule responsible for defense priming, followed by bioguided purification and molecular identification. This research represents a transition from proof-of-concept to mechanism elucidation, with potential for further development toward commercial biocontrol products.