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Linear mitochondrial plasmids of Fusarium oxysporum contain genes with sequence similarity to genes encoding a
H C Kistler1, U Benny, W A Powell
1Plant Pathology Department, University of Florida, Gainesville 32611-0680, USA. hck@gnv.ifas.ufl.edu
Abstract:
Two linear mitochondrial plasmids called pFOXC1 and pFOXC2 from the fungus Fusarium oxysporum were previously described. DNA sequence comparisons indicated that the derived amino acid sequences of both plasmids exhibit similarity to the reverse transcriptase of the Mauriceville and Varkud plasmids of Neurospora spp. The derived amino acid sequence of pFOXC2 has 51% similarity and 32% identity to the Neurospora reverse transcriptase; sequence similarity was greatest for seven blocks of amino acids that are conserved in reverse transcriptases from a wide range of biological sources. Northern analysis suggests that full-length RNAs corresponding to the plasmids are found in representative isolates.
Insights
Two linear mitochondrial plasmids, pFOXC1 and pFOXC2, from Fusarium oxysporum show similarity to reverse transcriptase enzymes. These findings suggest a potential role for these fungal plasmids in molecular processes.
Area of Science:
- Molecular Biology
- Mycology
- Genetics
Background:
- Two linear mitochondrial plasmids, pFOXC1 and pFOXC2, have been identified in the fungus Fusarium oxysporum.
- Previous research has established the existence and basic characterization of these plasmids.
Purpose of the Study:
- To investigate the molecular characteristics and potential functions of the pFOXC1 and pFOXC2 mitochondrial plasmids.
- To compare the genetic makeup of these fungal plasmids with known mobile genetic elements.
Main Methods:
- DNA sequence comparisons were performed between the Fusarium oxysporum plasmids and other known reverse transcriptases.
- Amino acid sequence similarities and identities were calculated to quantify the relationship.
- Northern blot analysis was utilized to detect the presence of full-length RNA transcripts corresponding to the plasmids.
Main Results:
- The derived amino acid sequences of pFOXC1 and pFOXC2 showed similarity to the reverse transcriptase of Neurospora spp. mitochondrial plasmids (Mauriceville and Varkud).
- Specifically, pFOXC2 exhibited 51% similarity and 32% identity to the Neurospora reverse transcriptase, with conserved amino acid blocks common to various reverse transcriptases.
- Northern analysis confirmed the presence of full-length RNAs for these plasmids in representative Fusarium oxysporum isolates.
Conclusions:
- The Fusarium oxysporum mitochondrial plasmids pFOXC1 and pFOXC2 possess sequences homologous to reverse transcriptases.
- These findings suggest that these plasmids may function as non-LTR retrotransposons or possess reverse transcriptase activity.
- The presence of corresponding RNAs indicates that these plasmids are transcriptionally active within the fungal mitochondria.