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ARS Home » Midwest Area » Wooster, Ohio » Application Technology Research » Research » Publications at this Location » Publication #420683
Research Project: Sustainable Production and Pest Management Practices for Nursery, Greenhouse, and Protected Culture Crops

Location: Application Technology Research

Title: Sclerotinia sclerotiorum growth and aggressiveness are regulated by a mycoviral REP protein

Author
item SHU, PEIHAN - University Of Wisconsin
item WU, CHIEN-FU - The Ohio State University
item LAWRENCE, ALEXANDER - University Of Wisconsin
item FENG, CHENCHEN - University Of Toledo
item KNOPKE-MOONEY, OLIVIA - University Of Wisconsin
item KIANI, YASI - University Of Wisconsin
item CHOWDHURY, RAWNAQ - University Of Wisconsin
item LADKY, DANNY - University Of Wisconsin
item GROVES, CAROL - University Of Wisconsin
item SMITH, DAMON - University Of Wisconsin
item Marzano, Shin-Yi
item RAKOTONDRAFARA, AURELIE - University Of Wisconsin

Submitted to: PLoS Pathogens
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: The rise of fungicide resistance requires novel strategies for combatting fungal pathogens. Using anti-microbial prediction tool and bioassays, we identified the replication-associated protein (REP) of Sclerotinia sclerotiorum hypovirulent-associated DNA virus 1 (SsHADV1) as a natural antifungal agent against economically significant fungal plant pathogens. The expression of the viral protein in plants primes defense responses and decreases fungal disease severity. In this study we engineered Bacillus subtilis as a delivery platform of REP anti-fungal protein to plants. It successfully prevented root rot infection of sunflower plants and weakened fungal aggressiveness. This work highlights the identification of novel source of anti-fungal agent and the promising new strategy for production of sprayable molecules bypassing the need of transgenic plants.

Technical Abstract: The heavy reliance on chemicals as the primary means of combatting fungal pathogens due to lack of sufficient resistance sources in plants has gradually led to the development of fungicide resistance in many fungal pathogens along with environmental toxicity. Hypovirulent mycoviruses offer a promising potential for developing sustainable bio-fungicides. This study investigated the hypovirulence mechanism by which Sclerotinia sclerotiorum hypovirulent-associated DNA virus 1 (SsHADV1), of the species Gemycircularvirus sclero1, impaired the necrotrophic plant fungi Sclerotinia sclerotiorum and Botrytis cinerea growth and pathogenicity. We identified the replication-associated protein (REP) of SsHADV1 as the key factor of its hypovirulence. RNAseq analysis of plant responses to the over-expression of SsHADV1 REP and fungal bioassays revealed two mechanisms at the base of this hypovirulence. First, SsHADV1 REP primes plant immune responses through up-regulation of the ethylene-signaling pathway. Second, SsHADV1 REP directly alters fungal growth and reduces oxalic acid production, which is an essential factor for pathogenicity. Using engineered Bacillus subtilis as an anti-fungal delivery platform, the secretion of SsHADV1 REP effectively reduced Sclerotinia sclerotiorum growth (P<0.05), and protected sunflower plants from root rot infection by the white mold. This method offers an innovative way to deliver biomolecules as part of a novel control strategy against fungal pathogens, bypassing the need for creation of transgenic plants.