The goal of this project is to determine the physiological and genetic basis underlying the potential production of more nutrient dense crops in farming systems. This will enable farmers interested in organic or conventional practices to integrate soil fertility systems that favor more sustainable production. It will allow plant breeders to develop crop cultivars suited for organic production.
Previously, we demonstrated that tomato fruit grown under an organic fertilizer regime had elevated phytonutrient content compared to tomato fruit grown under a conventional fertilizer regime. Using a comprehensive transcriptome analysis, we tested the following hypotheses: 1.) Growth under organic fertilizer regime will result in differential expression of the tomato genome and 2.) Genes and pathways associated with phytonutrients that were observed to be significantly higher under organic fertilizer regime will demonstrate higher expression. Both hypotheses tested true, indicating an adjustment of the plants’ genomic activity in response to a different nitrogen regime. We identified genes and associated pathways –among them, lycopene, ascorbate, soluble solids, and salvage pathways –which are expressed at higher levels under organic conditions.
The next logical step is to investigate the genomic response of roots after exposure to organic vs conventional fertilizer, to provide further understanding of how organic and conventional nitrogen are metabolized. We propose to test the following hypotheses: 1.) Different fertilizer regimes will elicit differential expression of nitrogen metabolism genes, and 2.) A different root/soil microbiome will be fostered under the two nitrogen conditions. This research includes a time course root/microbiome-targeted transcriptome analysis, focusing on genes and pathways associated with nitrogen metabolism and on the microbial symbionts activity favored under the different fertilizer conditions. Gene-based knowledge generated will facilitate identification of genotypes that utilize organic fertilizer more efficiently.
Short-term: We aim to increase knowledge of the relationship between phytonutrient content and underlying gene expression changes in plants when grown under organic or conventional soil fertility management systems in a model crop plant (tomato). We clarify here that promoting organic over conventional is not the goal of this study; rather, we hope to provide a basis for understanding of gene expression and metabolic differences, which may in turn result in nutritional differences, between the organic and conventional treatments. We aim to develop a model for comprehensive analysis in the field of crop production. We seek to use our study results to apply for grant funding in the USDA’s AFRI program in order to conduct a more comprehensive study, which will include field research.
Intermediate-term: Knowledge generated from the project, particularly with regards to organic vs. conventional nitrogen uptake and utilization as well as corresponding phytonutrient profiles in the different fertilizer regimes, will assist organic and sustainable producers to develop management plans for soil fertility. Understanding of gene function and of markers associated with genes expressed differentially under organic or conventional conditions will help plant breeders in the crossing and selection of more efficient crop cultivars that optimize both nutritional quality and yields of crops grown using more sustainable farming practices.
Long-term: Increase consumption of foods with improved nutritional quality, thereby contributing to the health of American children and adults and reducing health care costs. Implement more sustainable farming practices, particularly related to soil fertility and pest management, will enhance the quality of U.S. agro ecosystems. Contribute to the long-term economic viability of American farmers.
We are currently waiting for sufficient greenhouse space to begin the project. We have a solid experimental design planned. We will be analyzing the affects of organic vs conventional fertilizer on tomato roots and fruit. We will be looking at the root transcriptome, as well as the microbiome. Anticipated start date is September 2018.
Educational & Outreach Activities
Thus far, we have engaged in discussion with visitors to lab regarding the anticipated education and outreach activities. As we are still waiting on greenhouse space to begin the project (which will become available in November), we have been limited as to the extent of activities that can be conducted at this time.