U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Plant Science Research: St. Paul, MN
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area St. Paul, Minnesota Plant Science Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Samac, Deborah

                                                         - *Debby*item
                                            Dornbusch, Melinda

                                                         - *Mindy*
  Submitted to: International Conference on Legume Genomics and Genetics
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 6/7/2004
                                    Publication  Date: 6/7/2004
                                    Citation: Samac, D.A., Dornbusch, M.R. 2004. Gene expression in developing seed coats of Medicago sativa [abstract]. Second International Conference on Legume Genomics and Genetics, June 7-11, 2004, Dijon, France. p. 266.Interpretive Summary:
                                Technical Abstract: The parenchyma cells of seed coats and procumbent trichomes on leaves and stems are the only cells reported to contain proanthocyanidins (PAs; condensed tannins) in alfalfa (lucerne; Medicago sativa). In seed coats, PAs function in defense against insects and pathogens and in maintenance of seed dormancy. They may also have antinutritional properties in humans and monogastric animals by retarding protein digestion and micronutrient absorption. Expression of PAs in the foliage of alfalfa is desired to reduce the occurrence of pasture bloat, a potentially lethal foaming of digesta in the rumen from rapid breakdown of fresh alfalfa. The transparent testa and other Arabidopsis seed color mutants have greatly accelerated the cloning of genes in the PA biosynthetic pathway and understanding spatiotemporal regulation of flavonoid production. To better understand the regulation of PA biosynthetic genes in alfalfa, expression of genes involved in PA biosynthesis is being compared over time (2-34 days post-pollination) in developing seeds from alfalfa plants with wildtype tan-colored seed coats and dark brown-colored seed coats (UMN2163). The presence of PAs was visualized by staining with 4-dimethylaminocinnamaldehyde (DMACA). PAs were observed in seed coats of both genotypes at the first time point, 10 days post-pollination, in cells surrounding the hilum. By 14 days post-pollination, staining was observed over the entire surface of the seed. Staining was limited to the pallisade layer of cells of the seed coat. Red coloration of the seed coats of UMN2163 was observed from 10 to 34 days-post pollination. This line has similarity with the banyuls (ban) mutant of Arabidopsis in which anthocyanidin reductase is inactive, leading to increased anthocyanin accumulation in the seed coat. A nylon filter macroarray has been developed using cDNAs from Medicago truncatula. Included on the macroarray are 32 cDNAs for enzymes in the flavonoid biosynthetic pathway, including enzymes involved in isoflavonoid, lignin, anthocyanin, and PA biosynthesis, 14 cDNAs with sequence similarity to myb-like and myc-like transcription regulators, and 8 cDNAs of seed storage protein genes. Results of macroarray hybridizations using probes from young developing seeds of wildtype and UMN2163 alfalfa will be presented. This research may have implications for obtaining PA synthesis in alfalfa leaf mesophyll cells for management of pasture bloat.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov