| Popis: |
— The integration of molecular biology concepts and techniques in cultivated plant breeding programs allows defining more accurately the parents involved in crosses. The analysis of the DNA polymorphism in existing hop cultivars or wild types selected to generate new potent varieties is commonly used. Ribosomal DNA RFLP was the first to be studied in the middle of the 1990’s and differentiated at least European from North American cultivated hops. The EcoRI rDNA RFLP has been established here for a selection of 31 H. lupulus plants, 17 of which are cultivars and the remaining 14 include wild types and other genotypes used for breeding. The sequence of the Magnum variety rDNA EcoRI fragment (5,957 bp) covering the intergenic spacer and corresponding to its North American heritage has been determined. As mitochondria are known to play a role in the biosynthesis of the valuable plant secondary metabolites, specially those based on isopentenyl pyrophosphate, the search for mtDNA polymorphism allowing a possible distinction among hops was engaged. After having established the 14,472 bp sequence of mtDNA encompassing the ATP synthase alpha subunit (509 aa), a 560 bp region 5’ upstream of this gene allowed to identify a single nucleotide polymorphism. This SNP appeared to be maternally inherited in the lineage of Brewer’s Gold, often used in crosses for its bittering properties. This work may stimulate researchers to explore further on the role of mitochondria in the biosynthesis of metabolites, mainly but not only isoprenoids, that make Humulus lupulus so interesting. |
