Transposable elements of class II in Crinipellis perniciosa

This study reports the isolation and characterization of two class II transposable elements in the fungus Crinipellis perniciosa from sequences available in the data bank of the "Witch's Broom Genome" project. This fungus is of great economic importance once it is the causal agent of the most serious disease in cocoa crop. Previous acess to the data bank of the "Witch's Broom Genome" project allowed the identification of sequences with homology to known transposable elements belonging to the superfamilies Tc1/mariner and hAT. These sequences were used for the construction of oligonucleotides. An specific DNA fragment for each element was used as a probe for the isolation of the complete elements. These elements were isolated from C. perniciosa genomic bank constructed in the vector λEMBL3 (Stratagene) and named Mico and Guppy. The analysis of the partial sequence of Mico element in NCBI database showed high similarity to the DDE functional domain, which is a catalytic domain present in transposases of the superfamily Tc1/mariner. Conserved aminoacids regions were evidenced in the analysis of the partial sequence of Guppy element, although they did not indicate the presence of the I, II or III conserved domains (hATC), essential for the transposition activity of the elements of the superfamily hAT. The analysis of the expression of these elements performed in this study did not give evidence of the activity of these elements under stress conditions of temperature and salt concentration. The analysis xof distribution of Mico and Guppy elements in different isolates from different biotypes of C. perniciosa by PCR and hybridization techniques suggests the presence of polymorfic copies and the occurrence of subfamilies of these elements in C. perniciosa genome. The homogenic hybridization profile of Guppy element offers proofs that it may be a non-native element and may be acquired by a common ancestor of the biotypes. The hybridization profile of Mico element allowed the grouping of the different isolates of the biotype C relating to the different geographic regions from which the fungi were isolated, showing its potential as a molecular mark.