Double stranded DNA plasmids in the mitochondria of Trichoderma strains associated with green mould disease (original) (raw)
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Two linear plasmids in mitochondria of Fusarium solani f. sp. cucurbitae
Plasmid, 1988
Two linear plasmid-like DNAs designated pl?iCl (9.2 kbp) and pFSC2 (8.3 kbp) were found in an isolate of the plant pathogenic fungus Fusarium solani f. sp. cucurbitae race I. The plasmids were maternally inherited and copurified with mitochondtial DNA obtained from a mitochondria-enriched cell fraction suggesting that they are located in mitochondria. The plasmids did not share extensive sequence similarity. No homology was detected between either plasmid and the nuclear or mitochondrial genome when cloned plasmids were used as probes in Southern hybridization analyses. The fungus was cured of plasmids by ethidium bromide treatment. Compared to the plasmidcontaining isolate, plasmidcured derivatives had reduced pathogenicity on a suscep tible plant host, Cucurbita maxima "Pink Banana." 0 1988 Academic PET. IIW
Plasmid, 2002
A circular plasmid called pThr1, with a monomer size of 2.6 kb, was identified in the mitochondria of a Trichoderma harzianum isolate. Hybridization studies using cloned plasmids revealed no DNA sequence similarity between the plasmid and the mitochondrial genome of the isolate. The complete sequence of the plasmid was determined, and the sequence analysis revealed that it contained a single long open reading frame of 1818 bp. Sequence comparisons indicated that the derived amino acid sequence of the ORF exhibited similarity to the reverse transcriptases of the circular Mauriceville and Varkud retroplasmids of Neurospora spp. and the linear pFOXC2 and pFOXC3 retroplasmids of Fusarium oxysporum strains. In the regions of homology all of the seven conserved amino acid blocks characteristic of RTs could be found.
Plasmid-like DNAs in the commercially important mushroom genus Agaricus
Current Genetics, 1984
Two unique plasmid-like DNA components were localized in isolated mitochondria of the commercially important mushroom genus Agaricus: pEM (7.35 + 0.15 kilobases) and pMPJ (3.6 5 + 0.15 kilobases). These DNA moieties were linear; pEM possessed regions of terminal inverted repeated sequences. No homology was detected between pEM or pMPJ DNA and the nuclear or mitochondrial genomes. No homology existed between pEM and pMPJ. This suggests independent replication of pEM and pMPJ. Restriction endonuclease digests indicated that pEM consisted of two components (pEM1 and pEM2) with uniquely different restriction sites and copy number.
Extrachromosomal plasmids in the plant pathogenic fungus Rhizoctonia solani
Current Genetics, 1994
Extrachromosomal DNA elements were found in field isolates of Rhizoctonia solani belonging to anastomosis groups (AG) 1-5. An isolate of AG-5 (Rh41) contains a 3.6-kbp plasmid (pRS188) which has a similar A+T content to mitochondrial DNA. pRS188 is linear and has knob structures at its ends, as revealed by electron microscopy. Exonuclease digestions show that the linear ends of pRS 188 are protected, and remain protected even after proteinase K digestion, pRS188 does not hybridise to nuclear or mitochondrial DNAs of its host isolate (Rh41), to total DNAs of other plasmid-less AG-5 isolates, or to total DNA of plasmid-harbouring isolates belonging to different AGs. Cellular-fractionation experiments suggest that pRS 188 is associated with mitochondria, but it remains undecided whether this occurs inside or outside of the organelles. The nucleotide sequence of about 60% of the plasmid has been determined, revealing no open reading frame longer than 91 amino acids, and no known gene or genetic element is detected in the sequence contigs of 300-1572 bp length. Similar studies were performed with the plasmid pRS104 present in an isolate of AG-4 (Rh36), the sequence of which exhibits essentially the same features as pRS188 except that its A+T content resembles that of nuclear DNA. Pathogenicity tests reveal that the isolates Rh41 and R36 are as virulent as the plasmid-less isolates of AG-4 and -5, indicating that the plasmids do not play any role in pathogenicity.
Nucleic Acids Research, 1990
We have identified a plasmid-like element within mitochondria ofNeurospora crassa strain stp-B1. It is derived from the EcoRI-4 and EcoRI-6 regions of the mitochondrial DNA, and an additional 124 bp DNA segment of unknown origin. The plasmid DNA consists of an oligomeric series of circular molecules of monomer length 2.2 kbp. The abundance of the plasmid suggests its autonomous replication and the presence of an efficient origin of replication. An unusually large number of palindromes capable of forming secondary structures are present in the plasmid. Such a palindrome, located near sequences reminiscent of mammalian and fungal mtDNA origins of replication, may define the replication origin of the plasmid. This putative origin might also represent the replication origin of the wild-type mtDNA.
Nucleic Acids Research, 1982
Mitochondria from two Neurospora intermedia strains (P405-Labelle and Fiji N6-6) were found to contain plasmid DNAs in addition to the standard mitochondrial DNA species. The plasmid DNAs consist of monomeric circles (4.1-4.3 kbp and 5.2-5.3 kbp for Labelle and Fiji, respectively) and oligomers in which monomers are organized as head-to-tail repeats. DNA-DNA hybridization experiments showed that the plasmids have no substantial sequence homology to mtDNA, to each other, or to a previously characterized mitochondrial plasmid from N. crassa strain Mauriceville-lc (Collins et al. Cell 24, 443-452, 1981). The intramitochondrial location of the plasmids was established by cell fractionation and nuclease protection experiments. In sexual crosses, the plasmids showed strict maternal inheritance, the same as Neurospora mitochondrial DNA. The plasmids may represent a novel class of mitochondrial genetic elements.
Inheritance of mitochondrial DNA and plasmids in the ascomycetous fungus, Epichloë typhina
Genetics, 1996
We analyzed the inheritance of mitochondrial DNA (mtDNA) species in matings of the grass symbiont Epichloë typhina. Eighty progeny were analyzed from a cross in which the maternal (stromal) parent possessed three linear plasmids, designated Callan-a (7.5 kb), Aubonne-a (2.1 kb) and Bergell (2.0 kb), and the paternal parent had one plasmid, Aubonne-b (2.1 kb). Maternal transmission of all plasmids was observed in 76 progeny; two progeny possessed Bergell and Callan-a, but had the maternal Aubonne-a replaced with the related paternal plasmid Aubonne-b; two progeny lacked Callan-a, but had the other two maternal plasmids. A total of 34 progeny were analyzed from four other matings, including a reciprocal pair, and in each progeny the plasmid transmission was maternal. The inheritance of mitochondrial genomes in all progeny was analyzed by profiles of restriction endonuclease-cleaved mtDNA. In most progeny the profiles closely resembled those of the maternal parents, but some progeny ha...
A linear 10.4 kb plasmid in the mitochondria of Beta maritima
Current Genetics, 1989
A linear mitochondrial plasmid has been detected in the wild beet Beta maritima: the DNA molecule exhibits a molecular size of 10.4kb. Its restriction map differs from that of the 11.3 kb plasmid of Brassica, the only other example of a linear mitochondrial plasmid that has been reported in dicotyledonous plants. The 10.4 kb plasmid is widely distributed among natural B. maritima populations located along the French coast of the English Channel, and it is not correlated with the cytoplasmic male sterility occurring in this plant material. We report that the mitochondrial plasmid is transmitted to the progeny, but deviations from strict maternal inheritance have been observed.
Current Genetics, 1997
A 7.4-kilobase (kb) DNA plasmid was isolated from Glomerella musae isolate 927 and designated pGML1. Exonuclease treatments indicated that pGML1 was a linear plasmid with blocked 5′ termini. Cell-fractionation experiments combined with sequence-specific PCR amplification revealed that pGML1 resided in mitochondria. The pGML1 plasmid hybridized to cesium chloride-fractionated nuclear DNA but not to A + T-rich mitochondrial DNA. An internal 7.0-kb section of pGML1 was cloned and did not hybridize with either nuclear or mitochondrial DNA from G. musae. Sequence analysis revealed identical terminal inverted repeats (TIR) of 520 bp at the ends of the cloned 7.0-kb section of pGML1. The occurrence of pGML1 did not correspond with the pathogenicity of G. musae on banana fruit. Four additional isolates of G. musae possessed extrachromosomal DNA fragments similar in size and sequence to pGML1.