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*
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 8/3/1999
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary:
                                Technical Abstract: Expression of genes in genetically modified alfalfa requires gene promoters that regulate the inserted genes in a desired spatial and temporal pattern. Although a wide variety of promoters have been described from crop species, few have been tested for use in alfalfa. Using the beta-glucuronidase (GUS) reporter gene, we have characterized the expression patterns in transgenic  alfalfa of several nominally strong constitutive promoters, a number of alfalfa gene promoters, and several inducible promoters from heterologous species. The 35S promoter from the cauliflower mosaic virus is highly expressed in most cells of many crop plants. GUS activity in alfalfa leaves driven by the 35S promoter is 10- to 30-fold lower on a total leaf protein basis compared to activity in tobacco and Arabidopsis leaves, and we have observed rapid declines in GUS activity in alfalfa leaves of some plants as plants become more mature. Promoters tested from heterologous plants have  not demonstrated the same tissue specificity or level of expression as found in the original plant species. In alfalfa the Arabidopsis class III chitinase promoter lacks root-enhanced activity seen in Arabidopsis but is active in phloem and cambial cells of vascular tissues and is inducible by fungal pathogen infection. The potato protease inhibitor II (pin2) promoter has low constitutive activity in vascular tissues, root tips, and leaf mesophyll in alfalfa. Upon wounding leaves, GUS activity in leaves increases 2- to 3-fold over 24 hours. We have characterized a number of tissue-specific and inducible promoters that are suited for expressing new traits in alfalfa, although additional strong constitutive promoters are needed for biotechnology applications.


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