Location: Sunflower and Plant Biology Research
2018 Annual Report
Accomplishments
1. Identification of a mutation associated with floral regulation in Camelina sativa. Winter-annual biotypes of Camelina require a prolonged cold treatment to induce flowering, whereas summer-annual biotypes do not. Research directed towards identifying genetic factors controlling flowering in Camelina led ARS scientists in Fargo, North Dakota to discover a mutation that occurs at a greater frequency in a key floral regulatory gene of summer-annual compared to winter-annual biotypes. This mutation is predicted to enable flowering in summer-annual biotypes without a cold treatment, and has been used to develop a marker for distinguishing summer- and winter-biotypes early in seedling development. This discovery provides new knowledge for manipulating flowering time, which is an important trait for development of double cropping systems.
2. Identifying genes of Camelina sativa that control winter hardiness. Winter biotypes of Camelina regularly survive winter conditions experienced in North Dakota, whereas summer biotypes of camelina, and winter canola, are generally freezing sensitive to temperatures experienced in northern regions of the U.S. ARS scientists in Fargo, North Dakota analyzed changes in gene expression in response to cold temperatures in a winter- and a summer-annual biotype of camelina. Several novel genes were identified that may allow winter camelina biotypes to survive the harsh winter conditions experienced in North Dakota. These findings suggest that as few as two genes may regulate freezing tolerance. Identifying these cold-tolerance genes in camelina could provide tools for increasing winter hardiness in closely related species, such as canola, and help expand canola production in the U.S.
3. Planting date of winter oilseed cover crops affects winter survival in northern climates. Winter-hardy oilseed cover crops, such as Camelina sativa, provide value-added ecosystem services and double cropping options in northern regions of the U.S. The ability of these winter oilseed cover crops to provide maximum ecosystem services is dependent on their winter survival. ARS scientists in Fargo, North Dakota, in collaboration with scientists from North Dakota State University, demonstrated that planting date of winter biotypes is critical to the overwinter survival of Camelina sativa. Results from this collaborative field study conducted in Fargo, North Dakota indicated that seeds planted in mid- to late-September had the best overwinter survival, spring stand establishment, and yield. This information will provide land managers and extension personnel with the knowledge for making appropriate planting date decisions and recommendations.
4. Identification of signals regulating crop-weed interactions. Crops are proposed to detect weeds though altered light quality, through soil soluble chemical signals, and via volatile signals. ARS scientists in Fargo, North Dakota developed new approaches for separating these signals to determine how crops detect weeds and, more precisely, determined the developmental and physiological pathways that are activated when crops detect weeds. These protocols indicated direct root-to-root contact between the crop and weeds was required for maximum yield loss, regardless of nutrient and water availability. Identifying the signaling mechanisms and plant responses that allow crops to detect weeds could one day lead to the development of crops that are blind to competition, reduce herbicide use, and promote acceptance of cover crop and double cropping systems.
5. A specific weed-induced chemical defense signal in corn. Yield losses due to crop-weed interactions are caused by the costs of defense responses that are activated in crop plants, rather than direct competition with weeds for resources. With collaborators at South Dakota State University, ARS scientists in Fargo, North Dakota identified the involvement of a plant hormone-regulated gene pathway that is activated when weeds are present early in the growing season. Thus, inhibiting this pathway during the early growing season could make crops more tolerant of weeds and/or cover-crops. If successful, this approach will provide growers with a wider developmental window for weed control without loss of yield.
6. Developing Arabidopsis as an efficient model system to study plant-plant interactions. Studying crop-weed interactions is often difficult in genetically complex species such as corn and sunflower. ARS scientists in Fargo, North Dakota have demonstrated that Arabidopsis, the classic plant model, exhibits responses similar to crops under weed pressure. This system has been used to test the role of several regulatory and/or signaling genes suspected of controlling crop-weed interactions, such as genes known to impact plant response to overcrowding, and genes regulating plant defense responses. This model system provides a rapid method for functionally testing genes identified in crop-weed interaction studies.
7. Enabling the development of elite canola germplasm with increased winter hardiness. Short warm spells in the late fall and early spring often result in cold deacclimation, leaving crops such as winter canola vulnerable to subsequent return of freezing conditions. Identifying genes that prevent cold deacclimation in response to short periods of warm temperatures is a critical need for improving winter hardiness in winter canola. ARS scientist in Fargo, North Dakota determined the temperature thresholds and duration needed to initiate cold deacclimation and then used a population of winter canola varieties to identify chromosomal regions associated with the cold deacclimation response. Several genes known to be responsive to cold or involved in chromatin modifications in response to environmental conditions were identified. Manipulation of elite winter canola germplasm with these candidate genes will allow breeders to test their functional activity in enhancing winter hardiness.
Review Publications
Horvath, D.P., Bruggeman, S., Moriles-Miller, J., Anderson, J.V., Dogramaci, M., Scheffler, B.E., Hernandez, A.G., Foley, M.E., Clay, S. 2018. Weed presence altered biotic stress and light signaling in maize even when weeds were removed early in the critical weed-free period. Plant Direct. Available: https://onlinelibrary.wiley.com/doi/abs/10.1002/pld3.57.
Carvalho, L.J.C.B., Anderson, J.V., Chen, S., Mba, C., Dogramaci, M. 2018. In: Waisundara, V., editor. Cassava. Domestication syndrome in cassava (Manihot esculenta Crantz): Assessing morphological traits and differentially expressed genes associated with genetic diversity of storage root. Rijeka, Croatia. InTech. https://doi.org/10.5772/intechopen.71348.
Carvalho, L.J.C.B., Filho, J.F., Anderson, J.V., Figueiredo, P.G., Chen, S. 2018. Storage root of cassava: Morphological types, anatomy, formation, growth, development and harvest time. In: Waisundara, V., editor. Cassava. Rijeka, Croatia. InTech. https://doi.org/10.5772/intechopen.71347.
Horvath, D.P., Patel, S., Dogramaci, M., Chao, W.S., Anderson, J.V., Foley, M.E., Scheffler, B., Lazo, G., Dorn, K., Yan, C., Childers, A., Schatz, M., Marcus, S. 2018. Gene space and transcriptome assemblies of leafy spurge (Euphorbia esula) identify promoter sequences, repetitive elements, high-quality markers, and a full-length chloroplast genome. Weed Science. 66(3):355-367. https://doi.org/10.1017/wsc.2018.2.
Anderson, J.V., Horvath, D.P., Dogramaci, M., Dorn, K.M., Chao, W.S., Watkin, E.E., Hernandez, A.G., Marks, M.D., Gesch, R. 2018. Expression of FLOWERING LOCUS C and a frameshift mutation of this gene on chromosome 20 differentiate a summer and winter annual biotype of Camelina sativa. Plant Direct. 2:1-14. https://doi.org/10.1002/pld3.60.
Maroli, A.S., Gaines, T.A., Foley, M.E., Duke, S.O., Dogramaci, M., Anderson, J.V., Horvath, D.P., Chao, W.S., Tharayil, N. 2018. OMICS in weed science research: A perspective from genomics, transcriptomics and metabolomics approaches. Weed Science. https://doi.org/10.1017/wsc.2018.33.
Zhanga, L., Loua, J., Foley, M.E., Gu, X.-Y. 2017. Comparative mapping of quantitative trait loci for seed dormancy between tropical and temperate ecotypes of weedy rice (Oryza sativa L.). Genes, Genomes, Genetics. 7(8):2605-2614. https://doi.org/10.1534/g3.117.040451.
