Sequence of ITS-2 amplified from pearl millet downy mildew samples uri icon

abstract

  • DNA samples were isolated from fungal spores collected from leaves of pearl millet infected with downy mildew in India, Niger, Nigeria, Mali and Burkina Faso. Nested polymerase chain reaction was used to amplify the internal transcribed spacer region 2 (ITS-2) of the ribosomal RNA encoding genes. The first primers (ITS1 and ITS6) were in the conserved regions of the large and small subunit rRNA; the second pair (ITS 3 and ITS 4) flanked just the ITS-2 segment. The amplification of the ITS 2 region from presumed Sclerospora graminicola samples gave products of approximately 400 base pairs. BLAST searches of the GenBank showed that those from India and some from Africa were similar to the ITS 2 regions of other oomycetes, including Peronospora and Phytophthora species. The other African samples were clearly derived from other species. A tree constructed using the ITS 2 region of Cladosporium herbarum as an outgroup revealed the similarity of most isolates to other oomycetes, and that in general, the isolates collected from nearby locations were the most similar and that isolates from India were similar to those from Africa. However, it also showed that none of the ITS 2 sequences amplified from samples collected from Burkina Faso were from S. graminicola

publication date

  • 2005