Project Overview
Commodities
Practices
Proposal abstract:
Florida leads winter strawberry production in the United States, with farmers growing over 16,000 acres and generating more than $500 million in annual farm-gate value. However, disease management remains one of the most significant production challenges for Florida strawberry growers. In the past 10 years, a highly aggressive strain of Neopestalotiopsis rosea, the causal pathogen of pestalotia leaf spot (PLS), has emerged, causing major crop losses in Florida, spreading throughout the eastern U.S. and around the world. Current PLS management strategies are inadequate, as fungicides provide limited control and none of the commercial varieties highly adapted to Florida have sufficient disease-resistance. The entire southeastern strawberry industry is in dire of a solution, and the development of PLS-resistant cultivars remains the most sustainable and effective option.
The goal of our project is to accelerate the development of PLS-resistant strawberry cultivars by identifying and validating resistance-associated genes and translating these discoveries into practical molecular breeding tools. Using single-cell RNA sequencing, we will compare gene expression between resistant and susceptible genotypes during Neopestalotiopsis infection to identify candidate resistance genes. These genes will be functionally validated and subsequently, high-resolution melting markers will be developed to enable rapid, cost-effective screening of resistant seedlings in breeding programs. By integrating advanced genomics with applied breeding to hasten the development of PLS-resistant strawberry cultivars, this project will reduce reliance on chemical controls, decrease crop losses, and improve grower profitability. Ultimately, this work will strengthen the long-term environmental, economic, and operational productivity of the southeastern strawberry industry.
Project objectives from proposal:
OBJECTIVE 1: Identify genes associated with pestalotia leaf spot resistance in cultivated strawberry by comparing gene expression between susceptible and resistant genotypes.
RATIONALE: While our breeding program has identified Neopestalotiopsis-resistant germplasm, the molecular mechanisms underlying within-plant resistance remain poorly understood. We have narrowed the genomic region for one resistance locus (Alam et al. 2024), and preliminary work indicates the presence of a candidate susceptibility gene; additional gene candidates in the region must also be evaluated.
OBJECTIVE 2: Validate candidate genes contributing to disease resistance.
RATIONALE: Validation of candidate genes is a critical step to confirm their functional role in disease resistance. Functional validation will provide the foundational knowledge for the development of precise molecular markers for breeding. Although beyond the scope of this project, validated genes will also provide high-confidence targets for future gene-editing aimed at rapidly developing PLS-resistant cultivars.
OBJECTIVE 3: Design and implement high-resolution melting markers for efficient selection of pestalotia leaf spot-resistant seedlings.
RATIONALE: The development of gene-specific DNA markers will enable rapid, cost-effective identification of disease-resistant individuals during early-stage seedling selection (Jang et al. 2024). Furthermore, these markers will facilitate the pyramiding of favorable alleles, promoting durable and broad-spectrum resistance to Neopestalotiopsis rosae.