Folyt1, a new member of the hAT family, is active in the genome of the plant pathogen Fusarium oxysporum.
An active transposable element, Folyt1, has been isolated from the tomato pathogen Fusarium oxysporum f. sp. lycopersici as an insertion sequence within the coding region of the nitrate reductase gene (nit 1) in two independent mutants (CO66 and CO108). Folyt1 was 2615 bp in length and contained 9-bp imperfect inverted terminal repeats (ITRs) and 8 bp duplicated at the target site upon insertion. The element contained a long open reading frame interrupted by a single putative intron. The predicted amino acid sequence showed similarity to conserved domains of transposases from hobo, Ac, and Tam3 elements, which belong to the hAT family. The excision frequency of Folyt1 was determined to be less than 10(-5) in both mutants. These events restored the nit 1 wild-type allele without leaving footprints in all the revertants of strain CO66. Nevertheless, some revertants of strain CO108 showed a point mutation footprint at the target sequence. Expression of the Folyt1 transposase was detected by Northern analysis as a 2.1-kb transcript. The element exists in about 10 copies per genome in F. oxysporum f. sp. lycopersici and appears to be widely distributed among different formae speciales of F. oxysporum.
Gómez-Gómez
E
E
Departamento de Genética, Facultad de Ciencias, Córdoba, Spain.
Anaya
N
N
Roncero
M I
MI
Hera
C
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics*; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D005670:Fusarium / Q000235:genetics*; D016681:Genome, Fungal; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000235:genetics; D010935:Plant Diseases / Q000382:microbiology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D004251:DNA Transposable Elements; D004271:DNA, Fungal; D005656:Fungal Proteins; D009565:Nitrate Reductases; D050901:Nitrate Reductase