2013 Annual Report
1a.Objectives (from AD-416):
1. Identify molecular markers and their genetic map positions for priority sugar beet traits, including host plant resistance to curly top, root rots, and abiotic stresses. [NP301, C1, PS1B]
1.1. Whole genome re-sequencing of sugar beet public breeding line KDH13 for genetic variation analysis.
1.2. Identify a large representative set of single nucleotide polymorphism (SNP) markers for genotyping of mapping populations and germplasm.
1.3. Construct high density genetic linkage map to identify DNA markers closely linked to genes regulating resistance to curly top.
2. Improve germplasm screening procedures for host plant resistance, and incorporate disease management options into production practices through enhanced understanding of plant pathogen etiology and interactions with host resistance, pests, and abiotic stresses. [NP303, C3, PS3A]
2.1. Investigate curly top species variation and/or the presence of new curly top species in sugar beet.
2.2. Refine management strategies for curly top and pest control in sugar beet.
2.3. Establish the etiology and management options for an Athelia-like fungus associated with stored sugar beet roots.
2.4. Characterize and exploit the interaction of Rhizoctonia solani and Leuconostoc mesenteroides in sugar beet root rot to improve disease management options.
2.5. Determine the effect of rhizomania in the field on freeze damage to sugar beet roots in storage.
3. Identify novel sources of host plant resistance to diseases (curly top, rhizomania, and root rots), storage, and abiotic stresses (drought and frost), and incorporate them into adapted germplasm. [NP301, C1, PS1A]
1b.Approach (from AD-416):
Establish a research program to coordinate, interact and collaborate with university scientists to provide sustainable integrated disease and pest management strategies for sugar beet. New sugar beet germplasm with enhanced disease resistance and agronomic qualities will be developed, along with innovative and improved disease management strategies. Specific focus has been placed on alleviating crop losses due to curly top, rhizomania, root rots, spoilage during storage, and seedling frost injury. Genetic research will identify molecular markers associated with curly top resistance and establish their genetic map position. Understanding the etiology of pathogens associated with curly top, rhizomania, root rots, and storage losses, i.e., fungal decay, will lead to improved disease management options and screening methods. Using genetic methods with germplasm from the disease screening nurseries (curly top, rhizomania, Rhizoctonia-bacterial root rot, and storage), we will identify novel genes regulating traits of interest ultimately leading to public release of improved germplasm. New germplasm will be used by the sugar beet industry to enhance disease resistance and improve yields in commercial cultivars. The new genetic and pathogen knowledge generated will also allow our stakeholders to reduce losses by improved disease and postharvest storage management.
This report documents progress for this project, which started in June, 2013 and continues research from project 5368-21220-003-00D "Sugarbeet Germplasm Development and Innovative Genetic and Management Approaches to Reducing Losses Caused by Pathogens."
Objective 1. The KDH13 released germplasm has been identified for Genome re-sequencing. Two genomic libraries were constructed and sequenced using the HiSeq2000 next generation sequencing platform. The raw genome sequence has been assembled into a preliminary genome sequence (BvvSeq-1) which has been released by NCBI in GenBank.
Objective 2. Investigations into potential new curly top species have been initiated. Plants were selected in the field and DNA has been isolated. The samples are currently being characterized. The first year of investigating seed and foliar treatments for the control of curly top has been initiated. Research to establish the etiology of an Athelia-like fungus in storage has been initiated.
Objective 3. Screening for novel sources of resistance to curly top, BNYVV, Rhizoctonia solani, and storage has been initiated.
Sugar Beet Genome Sequenced. Only a draft reference genome (RefBeet-0.9) for sugar beet is publically available but has restrictions associated with its usage. Thus, a public reference genome without restrictions on usage needs to be established. ARS researchers at Kimberly, Idaho, in cooperation with SeqWright (private company with sequencing capability) have sequenced KDH13 (double haploid line developed by the ARS Kimberly researchers which carries curly top resistance). The raw genome sequence has been assembled into a preliminary genome sequence (BvvSeq-1) which has been released by NCBI in GenBank. These data should be useful for mapping and marker development in sugar beet and provides a gateway for investigations into genes controlling economically important traits.