Location: Sugarbeet and Potato Research
2019 Annual Report
Objectives
Coordinate the implementation of the pulse health initiative for expanded pulse crops research in the areas of health and nutrition, functionality, sustainability, and global food security. Research should be coordinated with interested ARS, state, and industry cooperators, and administered through non-assisted cooperative agreements. Planning workshops and annual meetings involving interested parties will be organized throughout the funding period.
Approach
Research will be conducted cooperatively to address the following research areas: Human Health and Chronic Disease Prevention; Functionality Traits and Food Security; and Sustainability of Pulse Production Systems. Targeted projects will focus on dry bean, dry pea, chickpea, or lentil research (or a combination of pulse crops) in the following priority areas: (1) Determine the role of pulse food consumption in a healthy diet with an emphasis on the biological mechanisms and impact on key health endpoints (e.g., glycemic control, cardiovascular risk factors, obesity/overweight, metabolic syndrome, inflammation, or microbiome composition); (2) Conduct well-designed and adequately controlled studies in humans that provide definitive data regarding the nutritional/health benefits of pulses as a component of a healthy diet; (3) Determine dietary consumption patterns of pulse foods and pulse food ingredients among U.S. consumers and the barriers and facilitators to pulse consumption; (4) Determine the role of dietary fiber, oligosaccharides, and other plant prebiotics from pulse crops in altering the composition and promoting beneficial attributes of a healthy gut microbiome; (5) Identify biomarkers of intake for various pulses; (6) Determine whether/how processing changes the health benefits or energy value of pulse foods consumed as part of a healthy diet; (7) Optimize processing conditions and formulations to improve the acceptability, flavor, nutritional value, or health attributes of foods made with pulses; (8) Develop high-throughput functionality measures that can be used by breeders and industry to assess functional characteristics of novel germplasm or current varieties; (9) Evaluate functional properties of protein and other pulse fractions/ingredients and optimize their use in food applications; (10) Determine the variability in chemical/nutritional composition of pulse crops and determine factors (agronomic, genetic or environmental) that influence that variation; (11) Determine factors (genetic or environmental) affecting the functional properties of pulse foods as ingredients in different food applications; (12) Develop pulse varieties with improved nutritional or functional attributes, combined with enhanced agronomic traits, and disease and pest resistance; (13) Assess the water footprint and demonstrate the value of improved water use efficiency in pulse-small grain cropping systems (e.g., field studies; life-cycle analyses); (14) Assess the carbon footprint and demonstrate the value of pulse cropping systems on the reduction of greenhouse gas emissions; (15) Develop improved pulse varieties that fix more nitrogen and identify enhanced plant-rhizobia interactions that yield superior nitrogen fixing capacity and leave greater residual nitrogen in soil; (16) Develop agronomic strategies to improve soil health through the incorporation of pulses in a cropping system rotation; (17) Assess the impact of incorporating pulses and expanding their use in the U.S. diet on sustainability outcomes.
Progress Report
This report documents progress for cooperative research performed as part of the Pulse Crop Health Initiative, and involves researchers at several U.S. universities and USDA-ARS locations, in cooperation with USDA-ARS in Fargo, North Dakota. The Initiative was started in FY18, with cooperative agreements established in late 2018. Progress is being reported in each of the Priority Research Areas (Food Technology, Breeding for Functional Traits, Sustainability, and Human Health Improvement).
Food Technology Research:
The composition of the cotyledon cell wall was characterized in a unique set of dry bean germplasm with diverse cooking times and culinary attributes. Wide genetic variability was identified for cotyledon cell wall thickness and seed coat length among a panel of dry beans with established fast and slow cooking properties. The cooking time of beans soaked for 6 to 24 hours was shown to be longer in bean genotypes with thicker raw seed cotyledon cell walls and the cooking time of unsoaked dry beans was longer in bean genotypes with longer seed coat osteosclereid cells.
The flour milling quality of dry bean germplasm with diverse cooking times was evaluated and iron bioavailability was measured in whole beans and foods made with bean flours. A sound wave milling technique was used to produce bean flours with low, medium and high protein concentrations. The degree of starch damage after milling beans into flour ingredients was significantly lower when compared to the degree of starch damage in milled wheat. Milling technique had a significant impact on color values of black bean flours, with the sound wave milling technique yielding darker colored flours, which can be beneficial to product appearance. The iron bioavailability of white and yellow beans increased significantly after heat-treated flour ingredients were formulated into fresh or extruded pasta.
Pea protein isolates (PPI) and hydrolysates (PPH) were produced to determine their structure, molecular interactions, surface properties, and functionality. Several extraction conditions including time, number of washes, pH, salt concentrations, and filtration methods were tested. Based on protein purity and yield data, two different extractions methods (alkaline extraction and salt solubilization) have been optimized, with yields over 60% and protein purity ranging from 80% to over 90%. Protein denaturation, protein profiling, and surface hydrophobicity data have been collected. Work is ongoing to produce the isolates on a larger scale, and compare structure and functionality as impacted by two drying mechanisms, freeze-drying and spray drying. Efforts are also underway to identify the aroma and taste compounds in PPI and PPH that provide an undesirable flavor.
In vitro studies were used to assess the effectiveness of food processing on reducing gas-producing oligosaccharides when consuming dry beans, peas, or lentils. Navy beans, green peas, and pardina lentils were processed using six common food processing operations and compared with unprocessed samples. All samples were subjected to in vitro digestion and fecal fermentation using the stool microbiome from 6 subjects and gas production by gut bacteria during the fermentation stage was analyzed. Processing method did not have a significant effect on rate of gas production; however, rate of gas production varied significantly among the 6 subjects and 2 of the 6 subjects showed significant differences among the bean/legume type.
Breeding for Functional Traits Research:
The genetic and environmental variation of protein and mineral nutrient concentration in current cultivars and advanced breeding lines of yellow pea were determined using multiple field locations. Replicated field trials (3 locations) of the 30 main yellow pea cultivars was planted in April 2019. A replicated diversity population of 482 yellow pea lines was also planted in April 2019 at one location. Molecular markers (SNPs) associated with alleles controlling protein concentration in pea will be determined using genome wide association studies (GWAS). DNA of 482 GWAS lines were submitted for genome-by-sequencing analysis to identify SNPs for mapping high seed protein concentration QTL.
Successful and consistent methodologies for transformation of pulse crops were investigated. Proof of delivery by transient beta-glucuronidase (GUS) assays were performed with common bean, using the cultivar Eclipse. The first putative transgenic Eclipse plant is currently growing and transgene transmission was validated via observation of stable expression of two marker genes in leaves and roots. Chickpea proof-of-concept experiments are underway. Transient gene expression in developing plants has been detected, supporting that DNA is being delivered to the correct cells in the meristem. Agrobacterium-mediated stable transformation was also confirmed using the meristem transformation approach in a Pinto bean cultivar. Progeny of initial primary transgenic plants have been grown, and proper segregation of the transgene validated by PCR and marker gene assays.
Efforts are in progress to enhance the nutritional and functional traits of dry bean through metabolomics, genetics, and breeding approaches. Multi-location field trials were completed to generate a large (~300) collection of advanced breeding lines from the major market classes of dry beans (pinto, great northern, navy, black) for subsequent metabolite fingerprinting. DNA was isolated from the same lines, and genotype-by-sequencing libraries were constructed so that metabolite and genotypic data can be analyzed using GWAS approaches. This will help identify molecular markers associated with specific bean metabolites. Advanced generation breeding lines (n=272) were also tested in replicated field trials during years 1 to correlate field performance with metabolite profiles. A set of three bean varieties (yellow, black, and white kidney) were milled into flour and made into pasta to determine the effect of processing on seed metabolites.
To identify promising breeding material for nutritional improvement in chickpea, 24 cafe kabuli chickpea varieties were harvested from two locations and analyzed for concentrations of several minerals and pre-biotic carbohydrates. Environment effects had a greater magnitude than genetic effects for all minerals but calcium. Significant genetic effects were detected for concentrations of several prebiotic carbohydrates, including mannitol, sucrose, and raffinose. Bioinformatic analysis of single nucleotide polymorphisms (SNPs) among 186 accessions from an ICRISAT chickpea ‘mini-core’ collection was conducted and 302,902 SNPs were identified that will be used in a chickpea GWAS study.
Sustainability Research:
To assess nitrogen (N) fixation potential in pulses, ten varieties of pea and lentil were seeded into cereal stubble in a randomized complete block design. Nitrogen fixation in pea was correlated to grain yield, grain protein, and grain N yield suggesting that by historically selecting for high yield, pea breeders might have also been selecting for high N fixation. In lentil, N fixation was not correlated to any of these parameters. Site selection commenced last fall for a potassium and sulfur study, with soil sampling for a range of parameters including nitrate, sulfate-S, and exchangeable potassium to identify locations within suitable fields that had relatively similar nutrient levels and had potential for an S response.
Winter pea varieties were established at three of four research locations to determine the relative productivity of spring and winter pea across a range of environments and cropping systems in Kansas. Abnormally wet weather throughout the fall delayed planting of winter peas at the fourth location until spring. Spring pea varieties were established at all four research locations. Initial results indicate that spring varieties established viable stands more consistently than winter varieties, but winter varieties bloomed 9 to 12 days sooner.
Life cycle assessment (LCA) of pulse crop production in the U.S. was started, with the scope of the LCA being from cradle-to-grave and an attempt to evaluate national average production and consumption practices for the most commonly grown peas, lentils, chickpeas, and dry beans in the U.S. Production of four types of pulses: chickpeas, lentils, field peas, and dry beans were modeled using OpenLCA. The attributional LCA system boundary was defined as cradle-to-grave; however, initial modeling efforts focused on production up to the farm gate for each of the four pulse crops. On-farm processes such as land preparation, planting, application of fertilizers and other chemicals, and harvesting were included.
Human Health Improvement Research:
Using animal models, studies were conducted to understand how energy balance is impacted by the consumption of common bean. An 84-day paired feeding study was completed in B6 male mice consuming a high fat diet, plus or minus white kidney bean. Both visceral and subcutaneous fat mass were significantly reduced by bean consumption. Studies were also conducted to determine the effect of common bean consumption on potential functional changes in the gut microbiome mediated by bean consumption. For animals in the experiment noted above, the size of the intestinal track was larger upon gross inspection at necropsy in bean fed mice and qPCR data indicated a 3.1-fold higher concentration of bacteria in the cecal content of bean fed mice. Additional studies were used to determine how energy balance and lipid metabolism are impacted by low and high dietary fiber cultivars of chickpea, dry bean, dry pea, and lentil. An experiment was completed using the male C57Bl6 mouse model of dietary induced obesity to assess both visceral and subcutaneous adipose depots.
Accomplishments
