2013 Annual Report
1a.Objectives (from AD-416):
Objective 1: Evaluate the potential of Danthonia spicata for turf use and establish the level of genetic diversity in the species for drought and low fertility tolerance.
Objective 2: Develop Agrostis germplasm with enhanced tolerance to biotic and abiotic stresses by improving methods to transfer desirable traits through interspecific hybridizations.
1b.Approach (from AD-416):
Identify, characterize, and develop grass germplasm suitable for turf uses with improved heat tolerance, disease tolerance, drought tolerance, water-use efficiency, and salt tolerance using conventional and molecular methods to improve the germplasm enhancement process. Emphasis will be placed on heat tolerance and disease resistance through the period of this project plan. Identify molecular markers and construct linkage maps of bentgrass (Agrostis spp.) that identify regions that impact heat tolerance. Work will also be conducted through cooperative agreements on low maintenance turfgrass species such as Koeleriamacrantha and Danthoniaspicata. Identify genetic markers for bentgrass foliar disease resistance to (dollar spot) and use them to select highly resistant Agrostisgermplams. Construct comparative maps to align genomes of selected forage and turf plants with cereal food crops and utilize this information to improve grass genetic resources.
Collect germplasm from natural grasslands worldwide of species having potential as turfgrasses; collaborate with forage, rangeland, and turfgrass scientists to identify, locate and collect germplasm. Study establishment, persistence, survival under different management strategies, and resistance to pests and diseases. Determine presence of endophytes, and whether endophytes affect resistance to pests, diseases, or environmental stresses. Examine physiology under different stresses and inputs to determine genetic mechanisms of resistance to biotic and abiotic stresses. Develop molecular markers from segregating populations, to allow introgression of desirable genes into germplasm with other valuable traits. Identify and isolate genes for resistance to pests and pathogens for potential genetic engineering of adapted selections. Create intra-specific, inter-specific, and inter-generic hybrids with superior turfgrass characteristics.
This report documents progress for this project and continues research from project 1230-21000-055-00D.
Under Objective 1, progress was made on determining reproductive and physiological aspects of Danthonia spicata, a native stress-tolerant grass species with potential for use as a low maintenance turf grass. SSR marker development and segregation studies strongly support apomixis as the mode of reproduction in this species. In addition, preliminary data suggest that seed coat transmitted symbiotic fungi and bacteria may be influencing growth habit and reproduction in Danthonia spicata.
Under Objective 2, Miniature Inverted Repeat Transposable Elements (MITEs) have been isolated from Agrostis species. MITEs are present in very high numbers in the Agrostis genome and genome-specific MITEs are being developed to be used in the identification of interspecific hybrids.
Native turfgrass development. Danthonia spicata, or poverty oatgrass, is a common native grass species that is drought tolerant, grows in soils with low fertility, and persists well in low pH and high iron soils commonly found on the east coast of the U.S. However, Poverty oatgrass germplasm collections exhibit extremely low levels of genetic diversity and have reproductive anomalies such as non-functional anthers and precocious seed development. ARS researchers in Beltsville, MD have discovered that endosymbiotic associations with bacterial and fungal species may be contributing to parthenogenic reproduction in poverty oatgrass and additionally may also enhance its ability to tolerate severe abiotic stresses such as drought and poor soil fertility. A better understanding of this grasses unusual reproductive biology and unique stress tolerance mechanisms could lead to the use of this species as a low-input, stress tolerant turf spcies.