This group focuses on developing and implementing the latest plant breeding techniques. Emphasis is primarily but not exclusively on ornamental crops. Aspects of interspecific hybridisation, stress imposed by tissue culture conditions, control over recombination and genome editing by CRISPR/Cas9 are some of the main research targets.
The research is on developing protocols, and also in generating markers for marker assisted breeding in diploids and polyploids, to identify, isolate and edit genes by using genetic and genomic tools coding for traits of interest and to provide approaches in improving the quality of micopropagated plants. Development of plant half-material, amongst others, by interspecific crosses, is a major point of attention. The group is also involved in preparing science-based position papers for the government on the New Plant Breeding Techniques such as cisgenesis and targeted mutagenesis by CRISPR-technology.
The genetics behind traits of interest for ornamental crops are studied by thorough monitoring of germplasm and phenotyping of mapping populations and association panels within newly developed trials. Emphasis is put on the assessment of determinants for complex traits. For complex traits or for traits that are costly or difficult to assess, linkage studies in progenies or association panels, either developed in house or by companies, are employed to identify molecular markers linked to specific traits or trait QTLs. This will allow indirect selection for these traits. The latest developments in Next Generation Sequence technology and High ThroughPut marker genotyping technologies are used for these mapping studies. Putative candidate genes for traits of interest are tested for co-localisation to earlier found QTLs. As most ornamental crops are characterized by their obligatory outcrossing nature and for a number of crops by higher ploidy levels, this requires the development of dedicated bioinformatics, marker scoring and mapping software, this in close interaction with other groups within Plant Breeding.
Interspecific crosses are made in order to introduce or generate new combinations of traits. Male and female fertility are monitored and pre- and post-fertilization barriers can be identified. Those barriers are studied and in many cases can be overcome technically, resulting in hybrids. Hybrid sterility can be overcome by ploidy manipulations but careful monitoring of interspecific hybrids for n or 2n gamete production is also performed. GISH is used to study levels of recombination in order to assess possibilities for introgression of desired traits into a recipient parent in backcrossing schemes.
Optimal conditions for such techniques are to be determined for each new species and we have a track-record in this area. Another major application of plant tissue culture is micropropagation: vegetative propagation in vitro. Micropropagation may produce very fast large numbers of vigorous plants with high quality and without endogenous pathogens. Micropropagation can be achieved by inducing outgrowth of axillary buds and suppressing apical dominance, by de novo synthesis of adventitous shoots or by somatic embryogenesis. Understanding the underlying mechanisms of some of the crucial steps in the processes mentioned above are studied aimed not only at improving the efficiencies, but also the quality of the plants produced. Because stress is a major cause of poor quality, quality improvement is tackled in a research project on stress related to tissue culture at the physiological, biochemical and molecular level. This should lead to practical solutions reducing the detrimental effects of stress imposed by the harsh environmental conditions in in vitro micropropagation. Another determining factor of growth and quality in tissue-cultured plants is nutrition. We are studying nutrient flows and parameters influencing it in tissue culture. The study of physiological factors as transpiration and photosynthesis is combined with a molecular genetic approach investigating the role of genes involved in carbohydrate partitioning.
Research is aimed at constantly updating that knowledge and improving the efficiency with which genetically modified plants can be generated. As the potential for GM crops to be commercialized is limited within the EU, the technique of genetic modification is primarily used for gene function analysis or for testing functionality. However, we also explore the application of several "New Plant Breeding techniques' (NPBTs), in particular cisgenesis and genome editing in a number of crops. These NPBTs reduce the time and effort needed to create new crop varieties. CRISPR/Cas9 or CRISPR/Cpf1 are preferred intruments for genome editing aimed at inducing targeted mutations. Possibilities for using the same techniques for true genome editing by allele replacement are being explored. Developing transient expression systems, e.g. involving protoplasts or using recombinant DNA-free delivery systems to plant cells, is aimed at producing improved plant varieties, that are not regarded as GMOs. Field trials with cisgenic plants, e.g. apples, are carried out to monitor performance in the field of this category of products of NPBTs.
Multi-environment QTL analysis of plant and flower morphological traits in tetraploid rose
Theoretical and Applied Genetics 131 (2018)10. - ISSN 0040-5752 - p. 2055 - 2069.
PolymapR-linkage analysis and genetic map construction from F1 populations of outcrossing polyploids
Bioinformatics 34 (2018)20. - ISSN 1367-4803 - p. 3496 - 3502.
Genetically engineering Crambe abyssinica- A potentially high-value oil crop for salt land improvement
Land Degradation and Development 29 (2018)4. - ISSN 1085-3278 - p. 1096 - 1106.
A high-quality genome sequence of Rosa chinensis to elucidate ornamental traits
Nature Plants 4 (2018). - ISSN 2055-026X - p. 473 - 484.
An ultra-dense integrated linkage map for hexaploid chrysanthemum enables multi-allelic QTL analysis
Theoretical and Applied Genetics 130 (2017)12. - ISSN 0040-5752 - p. 2527 - 2541.
Genetic mapping and QTL analysis of Botrytis resistance in Gerbera hybrida
Molecular Breeding 37 (2017)2. - ISSN 1380-3743
Erratum to: Genetic mapping and QTL analysis of Botrytis resistance in Gerbera hybrida : (Molecular Breeding, (2017), 37, 2, (13), 10.1007/s11032-016-0617-1)
Molecular Breeding 37 (2017)4. - ISSN 1380-3743
Etiolation and flooding of donor plants enhance the capability of Arabidopsis explants to root
Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 130 (2017)3. - ISSN 0167-6857 - p. 531 - 541.
Partial preferential chromosome pairing is genotype dependent in tetraploid rose
The Plant Journal 90 (2017)2. - ISSN 0960-7412 - p. 330 - 343.
Azacytidine and miR156 promote rooting in adult but not in juvenile Arabidopsis tissues
Journal of Plant Physiology 208 (2017). - ISSN 0176-1617 - p. 52 - 60.