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
 Crop Production and Pest Control Research: West Lafayette, IN
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area West Lafayette, Indiana Crop Production and Pest Control 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
- Small Grains Viral Disease Laboratory
- Corn and Sorghum Fungal Disease Laboratory
- Host Plant Resistance to Insects Laboratory
- Wheat/Hessian fly Interactions Laboratory
- Small Grains Fungal Disease Laboratory
- Soybean Quality Improvement Laboratory
- Uniform Soybean Tests, Northern Region

Title:   Author  item
                                            Goodwin, Stephen

                                                         - *Steve*item
                                            Zismann, Victoria
  Submitted to: Symposium Proceedings
                                    Publication Type: Proceedings
                                    Publication Acceptance Date: 9/21/1999
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary: Septoria passerinii is the causal agent of speckled leaf blotch of barley. This disease occurs in many barley production areas and can be severe when conditions are favorable to disease development.  The fungus was first described in 1879 and has been known since then only in an asexual state; a sexual stage is assumed, but has not been identified.  In culture, S.  passerinii looks very similar to the septoria tritici blotch pathogen of wheat, Mycosphaerella graminicola.  Both fungi have similar asexual spores and colony types on agar media.  The purpose of this research was to test the hypothesis that S. passerinii and M. graminicola are closely related. To do this, nucleotide sequences of the internal transcribed spacer (ITS) regions of the ribosomal DNA were obtained for both species and for a large number of other fungi.  Comparisons of the ITS regions of S. passerinii and M. graminicola showed that they differed by only 10 out of 571 nucleotides  and, therefore, these species must be very closely related.  Further comparisons with the ITS sequences of a large number of other fungi showed that S. passerinii and M. graminicola grouped together with other species of Mycosphaerella.  This answers a question first asked 120 years ago: the unknown sexual stage of S. passerinii must be Mycosphaerella.  This information will be useful to mycologists to better understand the taxonomy of the asexual form genus Septoria, and will help understand how new species of plant pathogens evolve in nature.  The information also may be useful to plant pathologists in controlling the disease, because control measures designed for the wheat pathogen M. graminicola also may be effective against its close relative on barley.
                                Technical Abstract: Septoria passerinii is known only from its anamorphic Septoria state; no teleomorph has been identified.  In culture, S. passerinii looks very similar to Mycosphaerella graminicola from wheat.  Comparisons of the nucleotide sequences of the internal transcribed spacer (ITS) regions of both species and of many other fungi in the Dothideales revealed that the  ITS regions of S. passerinii and M. graminicola differed by only 10 bases.  Therefore, these species are very closely related.  Phylogenetic analysis showed that S. passerinii and M. graminicola grouped together within a large cluster of Mycosphaerella species.  Thus, S. passerinii almost certainly has a Mycosphaerella teleomorph.


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