In the mitochondrion of eukaryotes, cytochrome b is a component of respiratory chain complex III. Cytochrome b is encoded by the
cytochrome b (CYTB) gene located in the mitochondrial genome. The fungicidal activity of QoIs relies on their ability to inhibit mitochondrial respiration by binding at the so-called Qo site (the outer quinol-oxida
Monospore B. cinerea field isolates has been collected during 2008-2009 from different hosts in Hungary. PCR fragment length analysis
indicated the high frequency presence of type large intron in the isolates while in a few strains G143A substitution could also be detected.
These results indicated the heterogeneity of CYTB in the Hungarian B. cinerea populations, which possibly involve the heteroplasmy of this
mitochondrial gene, moreover indicates the existence op azoxystrobin resistant populations in Hungary.
This work was supported by NKFP-A2-2006/0017 grant. Erzsébet Fekete is a grantee of the János Bolyai Scholarship (BO/00519/09/8).
The genes being in the mitochondrial DNA primarily encode the enzymes of cellular respiration. Fungicides belonging to the family of quinol oxidase inhibitors (QoIs) play on important role in the protection against several plant diseases caused by fungi. These fungicides bind to the cytochrome bc1 complex so they block electron transport betwee...n cytochrome b and cytochrome c1. This way these fungicides inhibit the ATP synthesis consequently they inhibit the mitochondrial respiration. The QoI resistance has two mechanisms. One of them is the point mutation of the cytochrome b gene (CYTB), e.g. the substitution of a single glycine by alanine at position 143 results in high-resistance. The other is the cyanide-resistant alternative respiration sustained by the alternative oxidase.
In a cell there are several mitochondria. The phenomenon when the genomes of all mitochondria in the cell are identical is called homoplazmy. If in the cell there is wild and mutant mitochondrial DNA this is called heteroplasmy. Whether the mutation in the mitochondria causes fenotypical diversity or does not depend on the dose, i.e. it depends on the percentage of the changed mitochondrials. During our work we investigated Botrytis cinerea single spore isolates which have been collected in 2008-2009 on different host plants. Our goal was to decide whether heteroplasmy influences the level of resistance. We managed to detect the change of the level of heteroplasmy, so the change the level of the resistance due to the treatment with fungicide.
The traditional Hungarian horse breed, Gidran has been close to the edge of extinction several times. Despite the multiple bottleneck effect, the breed has retained a part of its genetic variability, and performed prominently in carriage driving and show-jumping competitions. Maintaining of the Gidran breed is important in the point of view of...world heritage; because besides Hungary, smaller Gidran populations exist only in Bulgaria and Romania. Taking advantage of the special inheritance features of mtDNA, our study focused on two mtDNA regions of Gidran mares. Altogether, 251 hair samples from various Hungarian studs were examined. The analysis was successfully made in case of 251 samples of the cytochrome b and in case of 246 samples of D-loop regions. Because of the distinct mutation rates of the two mtDNA markers, the number of the haplotypes and the way of grouping samples into haplotypes was different. Our key finding was that most haplotypes may be compatible with mare families of the stud book; however incidental mistakes in stud book have occurred only in a few cases. Our results indicate the importance of the preservation and breeding those mare families, which are molecular genetically more diverse than the others, and are in the edge of extinction.
Hundred animal species have disappeared during the last century. By this time, approximately one-third of domestic animals have been in the endangered category. Hucul horses are also in this category; furthermore saving the genetic diversity beside the race preservation is an important challenge as well. The number of mares and stallions is onl...y one of the expressive elements of genetic diversity; together with their quality determine the genetic variability of this breed. Beyond that, if an exact breed can originates from more founders, it can be more renewed genetically. Stud book documents these data by registering the mare families and stallions’ genealogical lineage. Molecular genetics, especially mitochondrial DNA analysis can make the precise identification of mare families possible. As a result of these molecular based methods, protection of genetic diversity, as well as breed preservation became more reliable. After the primer designing, the optimal primer pair was chosen which targets a 1092 bp length DNA sequence in the cytochrome b region. After the successful PCR optimalisation, we determined 170 Hucul mares’ sequences. According to our results, the samples compose ten haplotypes, which are much less, than the registered number of mare families in the stud book. Further investigations are needed to reach more representative results, and drawn the further consequences.