Tracking a gene variant just by its expressed trait may prove quite laborious, time-consuming, and also imprecise.
Sometimes, indirect approaches may serve as an alternative for tracking gene variants. These approaches encompass molecular, physiological and/or biophysical methods. Whilst physiological and biophysical methods such as infrared spectroscopy (NIRS) provide information on the trait per se, molecular markers are able to depict the trait’s variation at the genetic level.
Molecular markers represent parts of DNA tightly linked to the gene variant of interest and, thus, tend to be transmitted conjointly with the gene-of-interest to the succeeding generation. Molecular markers can efficiently be checked via PCR methods in the lab, without the need to assess the manifestation of the respective trait. These and other methods of plant genomics allow for quick and accurate tracking of interesting gene variants along the breeding process. As part of our breeding research, we develop and apply strategies for precision breeding in order to pinpoint and tap valuable gene variants hold by plant genetic resources.
Ryegrass (Lolium sp.) is one of the economically most important forage grasses in Europe. Several pathogens cause a massive impairment, both for the pure mass yield and for the forage quality of ryegrasses. Furthermore, disease infestation has an impact on seed production, because infested plants do not form enough seeds. In view of the expected climate change, resistance to stem rust, crown rust and bacterial wilt are on the agenda. Our aim is to combine resistance genes against different diseases in ryegrass breeding lines or to pyramidise resistance genes that are effective against different pathogens.
Molecular markers can assist in the selection of relevant resistance genes. For the development of such markers, next-generation sequencing (NGS) techniques and bioinformatics approaches for large data sets are used, including the Massive Analysis of cDNA Ends (MACE) as a highly effective, transcriptome-wide analysis method for the detection of SNPs (single nucleotide polymorphism) and trait-specific transcripts. The combination of such NGS methods with the genetic approach of bulked segregant analysis has already enabled us to develop a highly effective and practical molecular selection marker for the black-rust resistance gene LpPg1 in L. perenne, which can be used directly for the breeding of resistant varieties.
Dr. Brigitte Ruge-Wehling