ARS | Publication request: POSSIBLE REPEAT INDUCED POINT MUTATION (RIP) IN CODING AND FLANKING REGIONS OF A TRANSPOSABLE ELEMENT FROM THE WHEAT PATHOGEN MYCOSPHAERELLA GRAMINICOLA

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: July 29, 2002
Publication Date: N/A

Technical Abstract: We previously identified a putative transposable element in a DNA fingerprint probe from the wheat leaf blotch pathogen Mycosphaerella graminicola. This transposable element is very stable. However, it moved occasionally in one isolate during asexual reproduction. The active copy and four inactive copies of the reverse transcriptase gene were cloned and sequenced. A high frequency of RIP mutations (G:C to A:T transitions) were found by DNA sequence comparison of these five clones. These mutations occurred not only in the reverse transcriptase gene coding region but also in the flanking region. All copies except the active one contain one or more stop codons within the coding region. Furthermore, most of the stop codon mutations were G:C to A:T, most likely due to RIP. By comparison, a single-copy gene from M. graminicola showed no evidence of RIP. This may provide the first evidence for RIP in a Loculoascomycete and indicates that RIP may be important for inactivating transposable elements for fungi in the genus Mycosphaerella.