Project Number: 8042-21000-305-000-D
Project Type: In-House Appropriated
Start Date: Aug 13, 2023
End Date: Aug 12, 2028
Objective 1: Enhance genetic resources for pepper and tomato through development of cultivars and breeding lines optimized for production in controlled environment agriculture and with durable resistance against major diseases. Sub-objective 1.A: Characterize and develop functional and regulatory mechanisms involved in anthracnose resistance for enhancement of tomato fruit rot resistance. Sub-objective 1.B: Develop and release tomato breeding lines and genetic stocks with novel traits that enhance adaptation to indoor vertical production CEA environments. Sub-objective 1.C: Exploit Capsicum germplasm resources to further characterize tospovirus resistance and introgress tomato chlorotic spot virus resistance into adapted culinary pepper breeding lines. Objective 2. Enhance genetic resources for potato by evaluating germplasm and developing improved varieties for heat tolerance, nitrogen use efficiency, and resistance against important microbial pests. Sub-objective 2.A: Screen diploid potato germplasm for common scab resistance and developing scab-resistant varieties. Sub-objective 2.B: Screen potato germplasm and develop varieties with improved agronomic performance under low nitrogen conditions. Sub-objective 2.C: Identify and characterize the physiological traits associated with internal heat necrosis in potato germplasm. Objective 3. Develop and utilize molecular biology and biotechnology tools to accelerate trait discovery and germplasm improvement of solanaceous vegetable crops for enhanced biotic and abiotic stress tolerance and adaptation to diverse production systems. Sub-objective 3.A: Develop TCSV-resistant pepper germplasm with potential broad-spectrum tospovirus resistance via RNAi-mediated silencing. Sub-objective 3.B: Generate transgenic solanaceous plants to test the role of specific genes in Verticillium wilt resistance in potato. Sub-objective 3.C: Characterization of molecular mechanisms involved in potato nitrogen use efficiency or nitrogen use efficiency-associated traits. Sub-objective 3.D: Elucidation of molecular pathways that distinguish susceptibility and tolerance to potato internal heat necrosis. Objective 4. Expand management options against important pathogens of solanaceous vegetable crops through characterization of pathogen populations, identification of virulence mechanisms, and testing of novel chemical and biological disease management tools. Sub-objective 4.A: Identify and test natural and synthetic chemical controls of common scab, late blight, and early blight of potato. Sub-objective 4.B: Characterize the diversity and distribution of pathogens that cause scab diseases of potato in the United States. Sub-objective 4.C: Identify and functionally characterize pathogen virulence factors in common scab of potato. Sub-objective 4.D: Identify and test endophytic microbes for control of biotic (common scab, early blight, late blight, and anthracnose) and abiotic (heat) stress.
Identification, selection, and manipulation of key plant and pathogens genes involved in plant-pathogen interactions or plant physiology will be performed through a variety of experimental pipelines. For tomato-anthracnose interactions, target genes involved in steroidalglycoalkaloid synthesis will be knocked down or overexpressed and impact on tomato disease susceptibility assessed through pathogen infection assays. For TCSV infection of pepper, transgenic pepper plants expressing constructs to silence the broad diversity of TCSV types through RNAi machinery will be transgenically expressed in pepper and tested for viral resistance. Standard traditional breeding approaches for introgressing TCSV resistance into pepper germplasm will be employed in parallel to identify and introgress that resistance into culinary germplasm. For potato, lines and cultivars with enhanced agronomic response to nitrogen, resistance to internal heat necrosis, and resistance to common scab disease will be identified through screening available potato germplasm resources in field and greenhouse trials. Genetic loci or biochemical pathways responsible for the desired traits will be identified through genome wide association studies or comparative metabolomics and transcriptomics between resistant and susceptible genotypes. The diversity of common scab pathogens in the United States will be examined through broad isolation of pathogens from infected tubers. Genomic analyses will be employed to identify key genes in virulence expression and the role of those genes will be tested through knockdown or overexpression. Chemical common scab disease suppression through low dose application of synthetic auxin analogs will be optimized through field trials with different spray regimens. The presence and effect of endophytic fungi on growth, yield and stress tolerance will be studied through use of fungal isolation and re-inoculation methods, using individual and mixed endophytic isolates. The role of endogenous application of melatonin, along with genetic manipulation of genes in the pathway of melatonin production will be examined to determine effects on biotic and abiotic stresses. The role of allelic diversity of Verticillium resistance genes in Verticillium wilt resistance will be tested through transgenic overexpression.