Powdery mildew (PM), a fungal disease, mainly caused by golovinomyces ambrosiae has devastating impacts on industrial hemp throughout north america resulting in significant crop loss

The Department of Agriculture National Institute of Food and Agriculture awarded Rutgers, The State University $875,854.05 on September 15, 2025, under the Grants for Agricultural Research, Special Research Grants program (CFDA 10.200) to develop genetic tools for powdery mildew resistance in industrial hemp.

The project generates a genetic powdery mildew resistance toolbox to accelerate development of resistant hemp strains. Work employs state-of-the-art genomic tools including RNA-seq and ATAC-seq at tissue and single-nuclei resolution to illuminate early infection stages of Golovinomyces ambrosiae on susceptible cultivars. The research combines genetic mapping of resistance genes and mildew locus O family genes to produce a candidate gene list of resistance regulators. CRISPR-Cas9 disruption of susceptibility genes will compromise fungal colonization; disruption of resistance genes will increase susceptibility. Field trials will test resulting genetic material, and promising strains will be made available to industry and research stakeholders. The work addresses significant crop loss from powdery mildew across North America and aims to reduce pesticide dependency while improving crop performance and food security.

Performance occurs in New Brunswick, New Jersey. The period of performance runs from September 15, 2025, through September 29, 2029. This is a project grant, the standard assistance type for NIFA agricultural research awards with project periods not to exceed three years; the source indicates this award extends four years, which may reflect a no-cost extension or a source data anomaly.

Unfortunately, the molecular architecture underlying PM resistance (PMR) in hemp is only poorly understood. This lack of knowledge about PMR regulators and the resulting absence of resistant genetic material is a major problem for hemp production in the US. The goal of the proposed research is to generate a genetic PMR toolbox which will accelerate the development of PM-resistant hemp strains allowing the creation of hemp plants with desirable traits more quickly than traditional breeding methods. To achieve this, we will illuminate the early infection stages of the PM-causing fungus golovinomyces ambrosiae on PM susceptible cultivars employing various state-of-the-art genomic tools (RNA-SEQ, atac-SEQ) at tissue and single nuclei level resolution. This will lead together with genetic mapping of resistance genes and the mildew locus o family (MLO) gene family to a candidate gene list of PMR regulators which will be disrupted using crispr-CAS9. Disruption of susceptibility genes will compromise the ability of g. Ambrosiae to successfully colonize hemp plants whereas the crispr/CAS9-mediated deletion of resistance genes will cause the opposite leading to increased susceptibility. The resulting genetic material will be tested for PMR in field trials and promising strains will be rapidly made available to industry and research stakeholders. This research, driven by grower requests, has the potential to greatly benefit the hemp industry by improving crop performance, mitigating crop loss and reducing the need for harmful pesticides.