Innovative Control of the Cucurbit Powdery Mildew: Combining Nanoencapsulated dsRNA and Low-Dose Fungicides for...

Area of Science:

• Plant Pathology
• Molecular Biology
• Agricultural Science

Background:

• Fungicide-resistant pathogens and strict regulations necessitate sustainable plant disease control methods.
• Succinate dehydrogenase inhibitor (SDHI) fungicides are crucial but face resistance issues.
• Podosphaera xanthii causes cucurbit powdery mildew, a significant agricultural problem.

Purpose of the Study:

• To evaluate spray-induced gene silencing (SIGS) targeting the SdhC gene for managing Podosphaera xanthii.
• To assess the synergistic potential of PxSdhC double-stranded RNA (dsRNA) with low-dose SDHI fungicides.
• To investigate the efficacy of nanoencapsulated dsRNA for enhanced stability and disease control.

Main Methods:

• Infiltration of PxSdhC dsRNA into melon cotyledons to assess gene silencing and fungal biomass reduction.
• Greenhouse trials using naked and carbon dot (CD)-nanoencapsulated dsRNA, alone and with boscalid/fluopyram.
• In vitro specificity assays to determine dsRNA's effect on different fungal species.

Main Results:

• PxSdhC dsRNA infiltration reduced fungal biomass by 65% and SdhC expression by 60%.
• Nanoencapsulation improved dsRNA stability, achieving up to 69% disease suppression.
• Combined treatments showed synergistic effects, with disease suppression ranging from 33% to 91% based on isolate resistance.

Conclusions:

• Gene-targeted, nanoformulated dsRNA is a promising strategy for integrated disease management.
• SIGS can enhance the performance of low-dose fungicide applications, reducing chemical input.
• This approach offers an effective, precise, and environmentally friendly alternative for controlling cucurbit powdery mildew.