Current Research Projects
Current research projects involve development of novel crop types, with a particular focus on hybrid vigour, and the incorporation of resistances to biotic and abiotic stresses from wild relatives into crops. Breeding for resistances offers a sustainable alternative to management practices such as use of sprays (insecticides, fungicides) and high levels of fertiliser application. Resistances to drought, heat and other environmental stresses are also critical for sustaining crop yields under climate change conditions. Our established research techniques include molecular genetics and genomics (bioinformatics) and molecular and classical cytogenetics as well as classical plant breeding methods.
Allohexaploid Brassica Species
Although the Brassica genus contains both diploid (2n = 2x; one set of chromosomes/genome) and allotetraploid (2n = 4x; two sets of chromosomes/genomes) species, no naturally occurring three-genome allohexaploid (2n = 6x) exists. We aim to synthesise novel allohexaploid Brassica genotypes and investigate genome stability and fertility in these lines. A new allohexaploid Brassica crop will hopefully demonstrate improved hybrid vigour and adaptability, allowing incorporation of useful traits from all six cultivated Brassica diploid and allotetraploid species.
Hybrid Speciation in Brassica
Presence or absence of additional chromosomes (aneuploidy) is a phenomenon found to be increasingly common in nature. We are interested in whether aneuploidy can lead to speciation, or at least formation of new, stable karyotypes in Brassica. Chromosome and allele inheritance in different populations of novel interspecific hybrid types are being tracked across generations to determine what role aneuploidy may play in hybrid speciation in Brassica, or if new, stable genomes can be established over time.
Recreating Genomically Stable Rapeseed
In order to increase genetic diversity in highly inbred crop rapeseed (Brassica napus), a common method is to “recreate” this species by making new hybrids between rapeseed progenitor species B. rapa and B. oleracea. However, these hybrids also have unstable genomes due to poor control of meiosis, and lose chromosomes, and hence essential genetic information for plant growth and fertility, from generation to generation. The reason for this genome instability is unknown, particularly since “natural” B. napus is genomically stable. We aim to investigate genomic stability in a large set of human-made hybrid rapeseed genotypes using high-throughput marker genotyping, fertility phenotyping and cytogenetics. Identification of the mechanism(s) of genomic stability in B. napus will not only provide fascinating insights into the evolutionary history of this species, but will be immediately useful for informing and assisting in transfer of useful genetic diversity into rapeseed.
Towards Autopolyploid Brassica Crops
Polyploids often have larger cell and organ sizes than diploids. Hence, induced polyploidy, where chromosome numbers within a species are artificially doubled, has great potential for plant breeding, particularly of root and vegetable crops. In turnip (diploid Brassica rapa) and related vegetable species, targeted breeding efforts in the 1970s and 80s resulted in the successful release of a number of tetraploid crop types. However, these polyploid induction breeding strategies were hindered by problems such as poor fertility and vigour, and were subsequently abandoned. We propose to use modern genotyping, sequencing and cytogenetics technologies to identify the factors responsible for success and failure of induced polyploidy breeding in these crops. Such hybrids have immense potential for yield improvement as a result of increased heterosis, if stable tetraploid crop types can be created on demand.
Introgressing Blackleg Resistance into Rapeseed
Crop wild relative/minor crop species black mustard (B. nigra) is known to carry novel several sources of resistance to major rapeseed (B. napus) crop pathogen blackleg (Leptosphaeria maculans, convar Phoma lingam). We aim to identify these novel resistance sources and introgress the genetic loci responsible into a rapeseed background, providing useful germplasm with blackleg disease resistance for further breeding efforts.
Homoeologous Recombination in Allopolyploids
How do stable allopolyploid species form? A question of general interest for many of our projects, we would like to identify genetic factors (genes, allelic variants, chromosome rearrangements) that contribute to increased or decreased homoeologous recombination and crossover frequencies in interspecific hybrids and polyploids, particularly in the Brassica genus.
NeatWheat
Nitrogen is an essential nutrient and often limits crop growth, but excessive fertilization is harmful to the environment. Therefore, it is imperative to develop cultivars with increased Nitrogen Use Efficiency (NUE) under normal and water scarcity conditions.
A preliminary GWAS study using 221 winter wheat cultivars identified the NPF2.12 gene, encoding a nitrate transceptor homolog, to regulate NUE at different levels of nitrogen supply. Allelic variants in the NPF2.12 promoter region were found to control root growth as well as nitrate uptake and translocation. Two distinct haplotypes (Hap1 and Hap2) were identified in winter wheat. Notably, HAP2 exhibited superior root development and higher nitrogen accumulation in the plant leaves when subjected to low nitrogen conditions (press release).
In our current study, we will characterize the root and yield traits of a set of selected genotypes showing extreme phenotypes. The root traits will be collected and the NUE will be evaluated. The segregation of the Hap1 an Hap2 of the NPF2.12 gene will be determined to validate previously reported association to root development and NUE.
For a better mechanistic understanding, tissue specific NPF2.12 expression will be analyzed and transport activity will be performed. By increasing the variability via genome-editing approaches, we intend to develop various alleles that will permit to analyse the regulatory mechanisms and select more efficient allelic variants.
Further, we are interested to estimate the dependency of NPF2.12-dependent NUE on water availability. For that, the extreme genotypes will be grown under different nitrogen levels both under drought and control conditions.
Based on the gained knowledge, the ultimate goal is to develop winter wheat cultivars with improved nitrogen use efficiency, particularly under low N and limited water availability.
