TY - JOUR
T1 - DNA transposon fossils present on the conditionally dispensable chromosome controlling AF-toxin biosynthesis and pathogenicity of Alternaria alternata
AU - Hatta, Rieko
AU - Shinjo, Akihisa
AU - Ruswandi, Sheila
AU - Kitani, Keiji
AU - Yamamoto, Mikihiro
AU - Akimitsu, Kazuya
AU - Tsuge, Takashi
N1 - Funding Information:
Acknowledgments We are grateful to Motoaki Kusaba, Tobin L. Peever, and L.W. Timmer for providing fungal strains, and to Motoichiro Kodama, Hirofumi Yoshioka, Kazuhito Kawakita, and Noriyuki Doke for valuable suggestions. This work was supported by Special Coordination Funds for Promoting Sciences from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, a Grant-in-Aid for Scientific Research from the Japanese Society for Promotion of Sciences (TT), and by a Research Fellowship of Japan Society for the Promotion of Science for Young Scientists (RH).
PY - 2006/8
Y1 - 2006/8
N2 - The strawberry pathotype of Alternaria alternata produces host-specific AF-toxin and causes Alternaria black spot of strawberry. Previously, we isolated cosmid clones pcAFT-1 and pcAFT-2 from strain NAF8 of the strawberry pathotype that contain AF-toxin biosynthetic genes, named AFT genes. In a molecular characterization here of pcAFT-1 and pcAFT-2, 11 AFT genes and five transposon-like sequences, named TLS-S1 to TLS-S5, were detected. The nucleotide sequences of TLS-S1 and TLS-S4 share high homology, and their putative products have similarity to transposases of the hAT family transposons. Thus, TLS-S1 and TLS-S4 were renamed TLS-S1-1 and TLS-S1-2, respectively. Amino acid sequences deduced from TLS-S2, TLS-S3, and TLS-S5 have similarity to transposases of the Fot1/Pogo family transposons, but they are significantly different. All five sequences have incomplete open reading frames (ORFs) for transposases owing to deletions, termination codons, and/or frameshifts, indicating that they are inactivated elements. Analysis of genomic distribution of these sequences revealed that they are specifically distributed on a 1.05-Mb chromosome of NAF8, which has been identified as a conditionally dispensable (CD) chromosome encoding AFT genes. The presence of three, four, and three copies of TLS-S1, TLS-S2, and TLS-S3, respectively, and a single copy of TLS-S5 on the CD chromosome were estimated by DNA gel blot analysis. The remaining copy of TLS-S1 and the three copies of TLS-S2 were isolated and identified to also encode incomplete ORFs. Thus, it appears that all copies of the transposon-like sequences identified are inactivated elements (fossils) unique to the CD chromosome in the genome of the strawberry pathotype.
AB - The strawberry pathotype of Alternaria alternata produces host-specific AF-toxin and causes Alternaria black spot of strawberry. Previously, we isolated cosmid clones pcAFT-1 and pcAFT-2 from strain NAF8 of the strawberry pathotype that contain AF-toxin biosynthetic genes, named AFT genes. In a molecular characterization here of pcAFT-1 and pcAFT-2, 11 AFT genes and five transposon-like sequences, named TLS-S1 to TLS-S5, were detected. The nucleotide sequences of TLS-S1 and TLS-S4 share high homology, and their putative products have similarity to transposases of the hAT family transposons. Thus, TLS-S1 and TLS-S4 were renamed TLS-S1-1 and TLS-S1-2, respectively. Amino acid sequences deduced from TLS-S2, TLS-S3, and TLS-S5 have similarity to transposases of the Fot1/Pogo family transposons, but they are significantly different. All five sequences have incomplete open reading frames (ORFs) for transposases owing to deletions, termination codons, and/or frameshifts, indicating that they are inactivated elements. Analysis of genomic distribution of these sequences revealed that they are specifically distributed on a 1.05-Mb chromosome of NAF8, which has been identified as a conditionally dispensable (CD) chromosome encoding AFT genes. The presence of three, four, and three copies of TLS-S1, TLS-S2, and TLS-S3, respectively, and a single copy of TLS-S5 on the CD chromosome were estimated by DNA gel blot analysis. The remaining copy of TLS-S1 and the three copies of TLS-S2 were isolated and identified to also encode incomplete ORFs. Thus, it appears that all copies of the transposon-like sequences identified are inactivated elements (fossils) unique to the CD chromosome in the genome of the strawberry pathotype.
KW - AF-toxin
KW - Alternaria alternata
KW - Class II transposon
KW - Conditionally dispensable chromosome
KW - Host-specific toxin
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U2 - 10.1007/s10327-006-0277-9
DO - 10.1007/s10327-006-0277-9
M3 - Article
AN - SCOPUS:33748125144
VL - 72
SP - 210
EP - 219
JO - Journal of General Plant Pathology
JF - Journal of General Plant Pathology
SN - 1345-2630
IS - 4
ER -