Abstract
Bremia lactucae Regel (Chromista, Peronosporaceae) is an economically destructive pathogen, which causes downy mildew disease on lettuce (Lactuca sativa L.) worldwide. The ribosomal internal transcribed spacer (ITS) of Bremia lactucae isolates was analyzed for the first time. The ITS region of lettuce downy mildew was observed to have a size of 2458 bp; thereby, having one of the longest ITS sizes recorded to date. The majority of the extremely large sized ITS2 length of 2086 was attributed to the additional presences of nine repetitive elements with lengths of 179-194 bp, which between them shared the low homology of 48-69%. Comparison of the ITS2 sequences with the B. lactucae isolates from other host plants showed that isolates present on Lactuca sativa were distinct from those on L. indica var. laciniata, as well as Hemistepta and Youngia. We suggest the high degree of sequence heterogeneity exhibited in the ITS2 region of B. lactucae may warrant the specific detection and diagnosis of this destructive pathogen or its division into several distinct species.
| Original language | English |
|---|---|
| Pages (from-to) | 91-95 |
| Number of pages | 5 |
| Journal | Mycopathologia |
| Volume | 163 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2007 Feb |
Bibliographical note
Funding Information:This study was supported by Ministry of Education and Human Resources Development in Korea (2005). The authors are grateful to the staff at the Korean Agricultural Culture Collection for their technical assistance in the DNA sequencing and phylogenetic analysis.
Keywords
- Downy mildew
- Heterogeneity
- Lettuce
- Repetitive elements
- Unexpected length
ASJC Scopus subject areas
- Microbiology
- Applied Microbiology and Biotechnology
- Agronomy and Crop Science
- veterinary (miscalleneous)