Analysis of transcriptional region found in a tomato pathotype-specific DNA fragment of Verticillium dahliae

Abstract

The DNA fragment (VDf130) specific to the tomato pathotype of Verticillium dahliae, cloned from the genomic DNA of the fungal isolate TV103, was confirmed to carry a transcriptional region. Assuming that the transcriptional region was a part of a gene (designated as vdtl), we sequenced the region containing its periphery and cDNA of the region. As a result, the transcriptional region contained a putative open reading frame coding for 137 amino acids separated by two introns. TATA box and CAAT box were also found upstream of the transcriptional region. However, vdtl or its presumed amino acid sequences did not show any significant homology to known genes or proteins in available data bases. Southern and Northern hybridization analyses showed that vdtl was found only in the isolates of the tomato pathotype among 19 tested isolates of V. dahliae and was transcribed in culture mycelia, spores, microsclerotia of TV103 as well as the tomato seedlings infected with the fungus.