2006 Annual Report
1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter?
This CRIS project is aligned with National Program 301- Plant Genetic Resources, Genomics, and Genetics Improvement.
Despite the global acceptance of dry bean (Phaseolus vulgaris L.) as a food source and the nutritional superiority of the seeds of this crop compared to cereals, root crops, and other vegetables, beans do not supply inherent nutrients to the fullest potential to humans. Poor digestibility of bean carbohydrates and protein is a major problem affecting the bean consumption. Dietary starch that does not digest is known as "resistant" starch. Resistant starch is a large contributor to gastrointestinal discomfort. The determination of indigestible starch will enable us to screen dry bean genotype of diverse origin for Total Dietary Fiber (TDF), resistant starch, and indigestible protein. With this knowledge, we can employ tools of molecular biology to locate (map) the genes controlling starch digestibility on specific chromosomes. DNA sequences located in the close proximity to the genes involved in digestibility and other food quality traits can then be used as markers to assist the breeding efforts and, thus, increase the efficiency of the breeding process.
Phytic acid, the major storage form of phosphorus (an important mineral for growth and development in plants) in dry bean seeds, reduces the bioavailability of zinc in human diets. Marginal zinc deficiency is a widespread problem, especially for people consuming vegetarian diets rich in food legumes to satisfy protein requirements. Because trace minerals, like zinc, are important not only for human nutrition but also for plant nutrition, plant breeding holds great promise for making a significant, sustainable, low-cost contribution to the reduction of micronutrient deficiencies in humans. Breeding for reduced levels of phytic acid along with increased zinc density will be a useful strategy to increase the amount of bioavailable zinc in diets.
Pigments imparting color to bean seed coats belong to a class of simple phenols known as flavonoids. Flavonoids obtained commercially and also those isolated from various plant species are known to be effective free radical scavengers. Compounds that disrupt free radical formation are called antioxidants. Condensed tannins and hydrolyzable tannins of high molecular weight are also known to be effective antioxidants and have greater antioxidant activity than the monomer flavonoids. The establishment of the relationship between the Mendelian genes controlling bean seed coat color synthesis and the individual flavonoids and tannins produced may open new opportunities for bean breeders to develop new germplasm that provides industry with opportunities of commercial potential as nutraceutical foods. Additionally, the resolution of the genes responsible for flavonoid and tannin formation, along with the antioxidant activity of these compounds may enable breeders to select for a range of antioxidant potential and, thus, balance antioxidant activity with antinutritional effects.
To enhance the food value of beans, several constraints must be resolved, and these form the objectives for the work of this project: a. Determine why beans are less digestible than other crops to improve the bioavailability of nutrients, b. Determine the chemical changes that occur in seeds causing polymerization of macromolecules and how these compounds interact to cause after-darkening and seed hardening during storage, c. Research the hard-to-cook defect that leads to prolonged cooking time, d. Reduce flatulence in beans, e. Determine the positive and negative effects of seed coat pigments (flavonoid and polyphenolic compounds) in human diets, f. Determine the inheritance of food quality component traits, and discover molecular markers associated with the traits to increase selection efficiency, and g. Release new cultivars in all market classes with improved nutrient bioavailability.
2.List by year the currently approved milestones (indicators of research progress)
1. Identification of cell structural factors:
a. Determine resistant starch (FY04)
b. Determine influence of mechanisms that entrap starch in cells (FY04-06)
c. Determine the effect of cell wall crystallization on cellular breakdown and cooking time (FY04-08)
2. Determination of the genetic basis of food quality traits:
a. Determine the inheritance of starch digestibility (FY04-08)
b. Determine the inheritance of protein digestibility (FY04-08)
c. Determine the inheritance of phytic acid (FY04-05)
d. Identify major genes affecting culinary quality traits (FY04-05)
e. Identify markers associated with seed coat microstructural traits (FY04-05)
f. Determine the role of the seed coat microstructure in water imbibition and color loss due to leaching in black beans (FY04-06)
3. Enhancement and release (germplasm):
a. Improved food quality (FY04-08)
b. Improved disease resistance (FY04-08)
c. Development of germplasm with shorter cooking times (FY04-08)
4. Isolation, identification, and characterization of seed coat flavonoids and determination of the relationship between seed coat color determining genes and the flavonoids they control:
a. Isolate, identify, and characterize seed coat flavonoids from selected genetic stocks (FY04-08)
b. Determine the function of P and B genes (FY04-08)
c. Determine the antioxidant potential of flavonoids (FY04-05)
4a.List the single most significant research accomplishment during FY 2006.
4b.List other significant research accomplishment(s), if any.
4c.List significant activities that support special target populations.
Effort was made to fill the critical SY position in FY06. A specific cooperative agreement was established between ARS and Michigan State University for collaborative research on measuring the level of folate in a diverse group of commercial bean genotypes that represent maximum diversity in seed types grown in the US.
5.Describe the major accomplishments to date and their predicted or actual impact.
1) This accomplishment is aligned with NP 301 Component 3 - Genetic Improvement of Crops, and it addresses Problem Statement 3C - Germplasm Enhancement/Release of Improved Genetic Resources and Varieties. Ten dry bean cultivars in seven market (commercial) classes and three small red germplasm breeding lines were cooperative releases between the Michigan Agricultural Experiment Station and/or the Washington Agricultural Research Center and USDA-ARS Sugarbeet and Bean Research Unit, East Lansing, Michigan. 'Kodiak' and 'Burke' pinto beans, 'Beluga' alubia bean, 'Chinook' light red kidney bean, 'Glacier' great northern bean, 'Phantom' and 'Jaguar' black beans all have high yields, acceptable to excellent canning quality, and multiple disease resistance. The high yields of these varieties may increase profits for small farmers who generally rely on a good production to offset profit risk because of a reduced farm size compared to large scale operations. The multiple disease resistance of these cultivars reduces the need to use chemicals, thus reducing production costs and protecting the environment. 'LeBaron' small red bean is early maturing and very upright in growth habit. Its attractive vegetative appearance and uniform "dry down" and early maturity has attracted growers to plant 'LeBaron' as a second crop in a double-crop production system. 'Rojo Chiquito' Central American red market class is the first small red with the dominant I gene form of resistance to bean common mosaic virus, and it has excellent canning quality with good firmness, and a very attractive bright red color after cooking. 'Rojo Chiquito' is becoming popular among Central American bean brokers and may represent a niche market for beans that are exported from the U.S. to this region. The erect, upright germplasm lines, ARS-R93344, ARS-R93346, and ARS-R93349 all have excellent dry seed appearance and good to excellent canning quality. These germplasms represent a significant improvement in the adaptation of small red beans for the humid Great Lakes region of the U.S. Midwest and likely will be valuable as parental lines in bean breeding programs.
2) This accomplishment is aligned with NP 301 Component 3 - Genetic Improvement of Crops, and it addresses Problem Statement 3A, Genetic Theory and Methods of Crop Improvement. We developed new and fundamental knowledge of cellular changes that occur during cooking of dry beans that lead to their ability to be digested. Heat induces cell walls to crystallize during the cooking process of dry beans. The cell wall crystallization forms a barrier that keeps water and digestive enzymes from solubilizing and breaking down starch. The indigestible starch passes through the gastrointestinal tract to the lower gut where microorganisms metabolize it, thus, producing gas, which is subsequently expelled. This research provided the important knowledge base needed to develop strategies for improving dry bean digestibility. Studies on genes differentially expressed during cell wall crystallization will aid in identifying and manipulating the genes controlling crystallization.
3) This accomplishment is aligned with NP 301 Component 3- Genetic Improvement of Crops, and it addresses Problem Statement 3A - Genetic Theory and Methods of Crop Improvement. Research showed that both the genotype and processing method affect the digestibility of dry beans. There were significant differences among a select sample of 41 dry bean genetic stocks for total dietary fiber, indigestible starch, and indigestible protein. Canned beans contained less total dietary fiber, and indigestible starch and protein than beans cooked in a pot on a stovetop. This research provides plant breeders with the knowledge needed to develop selection strategies to lower the indigestible residue in cooked beans. The finding that canned beans contained less indigestible starch and protein than beans cooked in a pot on a stovetop may influence a larger consumption of canned beans; thus, leading to higher profits for industry and increased nutrition for consumers.
4) This accomplishment is aligned with NP 301 Component 3 - Genetic Improvement of Crops, and it addresses Problem Statement 3A - Genetic Theory and Methods of Crop Improvement. We have determined that the flavonoids kaempferol 3-0-Beta-D glucoside and kaempferol 3-0-Beta-D-glucopyranoside-2 1-0-Beta-D xylopyranoside are the compounds responsible for yellow color in beans; the anthocyanins, delphinidin-3-o-glucoside, petunidin-3-0-glucoside, and malvidin-3-0-glucoside impart the black color to black beans; and the garnet red color of kidney beans is due primarily to proanthocyanidins which mask the yellow kaempferol flavonoids. This research was the breakthough needed to determine the function of genes in the biosynthetic pathway leading to the various flavonoid compounds involved in bean seed coat color. It will help bean breeders to develop new germplasm that provides industry with opportunities of commercial potential as nutraceutical foods.
5) This accomplishment is aligned with NP 306 Component 1- Quality Characterization, Preservation, and Enhancement and it addresses Problem Statement 1C-Factors and Processes That Affect Quality. An experiment was conducted in black bean to study water imbibition and its relationship to the thickness and continuity of the waxy cuticular layer of the seed coat. 'Shiny Crow' has a shiny seed coat and 'Raven' and 'Black Magic' both have opaque seed coats. Differences were detected between the three cultivars for thickness and continuity of the waxy epicuticular layer using scanning electron microscopy. In 'Shiny Crow' the epicuticular layer had a uniform thickness over the seed coat. The waxy epicuticular layers of 'Raven' and 'Black Magic' were of uneven thickness over the entire seed coat with areas varying in thickness by more than 1 micrometer. 'Black Magic' had the thickest epicuticular wax layer. Blanching in near boiling water (95 deg C) caused a breakdown of the waxy epicuticular layer in all three genotypes. Data from the experiment indicated that breakdown of the waxy epicuticular layer occurred most rapidly in the thinnest regions, allowing water to penetrate the seed coat faster than in the thicker regions. Since water uptake is a key factor in leaching of pigments in thermally processed black beans, the thickness of the waxy epicuticular layer may control the magnitude of pigment loss after canning in black beans. The research findings will be useful for the food canning industry in better management and control of bean canning operations.
6) This accomplishment is aligned with NP 301 Component 3 - Genetic Improvement of Crops, and it addresses Problem Statement 3C - Germplasm Enhancement/Release of Improved Genetic Resources and Varieties. An experiment was conducted to develop baseline data for cooking time on representative genotypes of several market classes that are of interest to growers who export beans to Central America and the Caribbean. Pinto beans were the fastest cooking among the seven market classes studied and small-red beans were the slowest cooking (110.3 min on average). There was a negative relationship (r = -0.84) between cooking time and water absorption. Since fast-cooking beans imbibed more water than slow-cooking ones, water absorption should be useful to predict cooking time in beans. Breeders should be able to select fast cooking genotypes from slow cooking ones. Selection based on the water absorption of a breeding line as an indirect estimation of its cooking time is rapid and saves resources.
6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
We provided new information to the scientific community and to bean grower and shipper industries on the importance of beans in a healthy diet and on important findings on the digestibility of beans and methods for improving the bioavailability of nutrients in this crop. New knowledge based on our research provided a basis to improve the health and nutrition of civil society. New cultivars of dry beans in several market classes were released to industry. These new cultivars have the potential of enhancing the profitability to growers and reducing costs for consumers. Cultivar releases in the small red market class have the potential to replace existing varieties grown in the humid Midwest, which will help stabilize production and grower income. In addition, disease resistance in the cultivars reduces the reliance on agricultural chemicals to control diseases and insect pests, thus, protecting the environment and reducing production costs. Several major consultations with the national media led to the publication of major articles publicizing our findings on flavonoids and their antioxidant potential and other health benefits obtained from including beans in the diet.
New and improved cultivars have been released to industry and are currently being used by growers. New knowledge on digestibility and the health benefits from eating beans has been published in the national media and presented at health workshops.
7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).