Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence
Bacterial wilt, caused by Ralstonia solanacearum, is a serious disease of tobacco in North and South Carolina. In contrast, the disease rarely occurs on tobacco in Georgia and Florida, although bacterial wilt is a common problem on tomato. We investigated whether this difference in disease incidence...
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| Format: | Article |
| Language: | English |
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The American Phytopathological Society
2004-12-01
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| Series: | Molecular Plant-Microbe Interactions |
| Subjects: | |
| Online Access: | https://apsjournals.apsnet.org/doi/10.1094/MPMI.2004.17.12.1376 |
| _version_ | 1811290277295423488 |
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| author | Alison E. Robertson W. Patrick Wechter Timothy P. Denny Bruce A. Fortnum Daniel A. Kluepfel |
| author_facet | Alison E. Robertson W. Patrick Wechter Timothy P. Denny Bruce A. Fortnum Daniel A. Kluepfel |
| author_sort | Alison E. Robertson |
| collection | DOAJ |
| description | Bacterial wilt, caused by Ralstonia solanacearum, is a serious disease of tobacco in North and South Carolina. In contrast, the disease rarely occurs on tobacco in Georgia and Florida, although bacterial wilt is a common problem on tomato. We investigated whether this difference in disease incidence could be explained by qualitative characteristics of avirulence gene avrA in the R. solanacearum population in the southeastern United States. Sequence analysis established that wild-type avrA has a 792-bp open reading frame. Polymerase chain reaction (PCR) amplification of avrA from 139 R. solanacearum strains generated either 792-bp or ≈960-bp DNA fragments. Strains that elicited a hypersensitive reaction (HR) on tobacco contained the 792-bp allele, and were pathogenic on tomato and avirulent on tobacco. All HR-negative strains generated a ≈960-bp DNA fragment, and wilted both tomato and tobacco. The DNA sequence of avrA in six HR-negative strains revealed the presence of one of two putative miniature inverted-repeat transposable elements (MITEs): a 152-bp MITE between nucleotides 542 and 543, or a 170-bp MITE between nucleotides 461 and 462 or 574 and 575. Southern analysis suggested that the 170-bp MITE is unique to strains from the southeastern United States and the Caribbean. Mutated avrA alleles were present in strains from 96 and 75% of North and South Carolina sites, respectively, and only in 13 and 0% of the sites in Georgia and Florida, respectively. Introduction of the wild-type allele on a plasmid into four HR-negative strains reduced their virulence on both tobacco and tomato. Inactivation of avrA in an HR-positive, avirulent strain, resulted in a mutant that was weakly virulent on tobacco. Thus, the incidence of bacterial wilt of tobacco in the southeastern United States is partially explained by which avrA allele dominates the local R. solanacearum population. |
| first_indexed | 2024-04-13T04:10:05Z |
| format | Article |
| id | doaj.art-9b81f9f966f642ada7b18a32506b3d0e |
| institution | Directory Open Access Journal |
| issn | 0894-0282 1943-7706 |
| language | English |
| last_indexed | 2024-04-13T04:10:05Z |
| publishDate | 2004-12-01 |
| publisher | The American Phytopathological Society |
| record_format | Article |
| series | Molecular Plant-Microbe Interactions |
| spelling | doaj.art-9b81f9f966f642ada7b18a32506b3d0e2022-12-22T03:03:08ZengThe American Phytopathological SocietyMolecular Plant-Microbe Interactions0894-02821943-77062004-12-0117121376138410.1094/MPMI.2004.17.12.1376Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt IncidenceAlison E. RobertsonW. Patrick WechterTimothy P. DennyBruce A. FortnumDaniel A. KluepfelBacterial wilt, caused by Ralstonia solanacearum, is a serious disease of tobacco in North and South Carolina. In contrast, the disease rarely occurs on tobacco in Georgia and Florida, although bacterial wilt is a common problem on tomato. We investigated whether this difference in disease incidence could be explained by qualitative characteristics of avirulence gene avrA in the R. solanacearum population in the southeastern United States. Sequence analysis established that wild-type avrA has a 792-bp open reading frame. Polymerase chain reaction (PCR) amplification of avrA from 139 R. solanacearum strains generated either 792-bp or ≈960-bp DNA fragments. Strains that elicited a hypersensitive reaction (HR) on tobacco contained the 792-bp allele, and were pathogenic on tomato and avirulent on tobacco. All HR-negative strains generated a ≈960-bp DNA fragment, and wilted both tomato and tobacco. The DNA sequence of avrA in six HR-negative strains revealed the presence of one of two putative miniature inverted-repeat transposable elements (MITEs): a 152-bp MITE between nucleotides 542 and 543, or a 170-bp MITE between nucleotides 461 and 462 or 574 and 575. Southern analysis suggested that the 170-bp MITE is unique to strains from the southeastern United States and the Caribbean. Mutated avrA alleles were present in strains from 96 and 75% of North and South Carolina sites, respectively, and only in 13 and 0% of the sites in Georgia and Florida, respectively. Introduction of the wild-type allele on a plasmid into four HR-negative strains reduced their virulence on both tobacco and tomato. Inactivation of avrA in an HR-positive, avirulent strain, resulted in a mutant that was weakly virulent on tobacco. Thus, the incidence of bacterial wilt of tobacco in the southeastern United States is partially explained by which avrA allele dominates the local R. solanacearum population.https://apsjournals.apsnet.org/doi/10.1094/MPMI.2004.17.12.1376insertion sequence |
| spellingShingle | Alison E. Robertson W. Patrick Wechter Timothy P. Denny Bruce A. Fortnum Daniel A. Kluepfel Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence Molecular Plant-Microbe Interactions insertion sequence |
| title | Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence |
| title_full | Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence |
| title_fullStr | Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence |
| title_full_unstemmed | Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence |
| title_short | Relationship Between Avirulence Gene (avrA) Diversity in Ralstonia solanacearum and Bacterial Wilt Incidence |
| title_sort | relationship between avirulence gene avra diversity in ralstonia solanacearum and bacterial wilt incidence |
| topic | insertion sequence |
| url | https://apsjournals.apsnet.org/doi/10.1094/MPMI.2004.17.12.1376 |
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