Location: Crop Improvement and Protection Research
2013 Annual Report
1. Promoting sugar beet research concerning the isolation of specific genes and the development of germplasm, which may be used effectively in breeding to develop hybrids and varieties that are resistant to various pathogens, regionally adapted, suitable for various cultural practices, superior in biochemical attributes, and storable with minimum deterioration.
2. Establishing technology whereby new genetic characters, inbred lines, or sugar beet germplasm established via ARS research may be brought into widespread use by breeders and growers promptly, efficiently and at less cost.
3. Promoting research to develop better disease management, through an increased understanding of sugar beet disease etiology and epidemiology and an elucidation of the biochemistry, physiology and genetics of the sugar beet-pathogen-biocontrol agent interaction.
4. Increasing the understanding of the biochemical genetic and physiological basis of the development of the sugar beet plant, the storage of the harvested root and the extraction of sucrose from the beet to be better able to maximize the efficiency in the processing of sugar beet to sucrose and other products.
5. Evaluating, characterizing, and utilizing available genetic resources (esp., in the USDA-ARS Nanometer Pattern Generation System Beta vulgaris proprietary inbred germplasm collection) to determine the genetic diversity within sugar beet and pathogen populations, to better understand and manage important pathogens of sugar beet, and to produce enhanced germplasm more rapidly and more efficiently to meet the changing needs of seed companies and the growers they serve.
Documents Nonfunded Cooperative Agreement with Beet Sugar Development Foundation.
In an effort to determine the nature of SBCN resistance and how it is inherited, 13 mapping populations with different donor parents were advanced to the F2:3 generation. Future genotyping and phenotyping efforts with this germplasm will lead to mapping each source of resistance and identifying linked molecular markers for marker-assisted introgression.
Genotyping efforts identified 11 markers polymorphic between and within sugar beet and wild relatives, specifically Beta vulgaris subspecies maritima and Beta macrocarpa. These markers will be applied in bulked segregant analyses and ultimately marker-assisted introgression efforts. These selected markers are transferrable across wild Beta species allowing identification of potential genetic exchange between sugar beet and Beta vulgaris subspecies maritima or Beta macrocarpa.
Four loci have been sequenced from a range of Rhizoctonia solani Anastamosis Group 2-2 isolates recovered from sugar beet, and phylogenetic analysis demonstrated that the intraspecific groups IIIB and IV do not reflect evolutionary relationships. A new intraspecific classification scheme will be proposed.
Studies are examining incidence and genetic variation among curtovirus species and strains collected from crops and weeds in California during the severe virus outbreak in 2013. These viruses cause curly top disease of sugarbeet and other crops. The project seeks to identify potential changes in the populations of viruses causing curly top and monitor for the emergence of new variants with altered severity and host range.
Single-spore isolates of Polymyxa betae are being used to evaluate the potential for resistance in sugarbeet to this vector of several important soil-borne viruses, including Beet necrotic yellow vein virus (BNYVV), which causes rhizomania disease.
Proteomic profiling was conducted on susceptible sugarbeet, infected with BNYVV, to clarify the types of proteins prevalent during compatible virus-host plant interactions. Most proteins identified were associated with photosynthesis and energy, metabolism, and plant response to pathogens or other stress factors. Many previously identified proteins have been associated with systemic acquired resistance and general plant defense responses, particularly those mediated by reactive oxygen species. These results expand on limited proteomic data available for sugarbeet and provide a basis for future studies focused on understanding the interaction of BNYVV with sugarbeet.