Using wild relatives and related species to build climate resilience in Brassica crops.

Climate change will have major impacts on crop production: not just increasing drought and heat stress, but also increasing insect and disease loads and the chance of extreme weather events and further adverse conditions. Often, wild relatives show increased tolerances to biotic and abiotic stresses, due to reduced stringency of selection for yield and yield-related traits under optimum conditions. One possible strategy to improve resilience in our modern-day crop cultivars is to utilize wild relative germplasm in breeding, and attempt to introgress genetic factors contributing to greater environmental tolerances from these wild relatives into elite crop types.

A novel deletion in FLOWERING LOCUS T modulates flowering time in winter oilseed rape.

A novel structural variant was discovered in the FLOWERING LOCUS T orthologue BnaFT.A02 by long-read sequencing. Nested association mapping in an elite winter oilseed rape population revealed that this 288 bp deletion associates with early flowering, putatively by modification of binding-sites for important flowering regulation genes.

Long-read sequencing reveals widespread intragenic structural variants in a recent allopolyploid crop plant.

Genome structural variation (SV) contributes strongly to trait variation in eukaryotic species and may have an even higher functional significance than single-nucleotide polymorphism (SNP). In recent years, there have been a number of studies associating large chromosomal scale SV ranging from hundreds of kilobases all the way up to a few megabases to key agronomic traits in plant genomes. However, there have been little or no efforts towards cataloguing small- (30-10 000 bp) to mid-scale (10 000-30 000 bp) SV and their impact on evolution and adaptation-related traits in plants.

Transcriptomics reveal high regulatory diversity of drought tolerance strategies in a biennial oil crop.

Spring droughts are expected to become more frequent in Central Europe as a result of climate change. Their coincidence with flowering of biennial crops like winter oilseed rape (Brassica napus) can cause major impact for yield development. However, no data is available on the diversity of genetic regulation of drought tolerance during this stage under realistic conditions.

The vernalisation regulator FLOWERING LOCUS C is differentially expressed in biennial and annual Brassica napus.

Plants in temperate areas evolved vernalisation requirement to avoid pre-winter flowering. In Brassicaceae, a period of extended cold reduces the expression of the flowering inhibitor FLOWERING LOCUS C (FLC) and paves the way for the expression of downstream flowering regulators. As with all polyploid species of the Brassicaceae, the model allotetraploid Brassica napus (rapeseed, canola) is highly duplicated and carries 9 annotated copies of Bna.

"Doubled-haploid" allohexaploid Brassica lines lose fertility and viability and accumulate genetic variation due to genomic instability.

Microspore culture stimulates immature pollen grains to develop into plants via tissue culture and is used routinely in many crop species to produce "doubled haploids": homozygous, true-breeding lines. However, microspore culture is also often used on material that does not have stable meiosis, such as interspecific hybrids. In this case, the resulting progeny may lose their "doubled haploid" homozygous status as a result of chromosome missegregation and homoeologous exchanges.

Inherited allelic variants and novel karyotype changes influence fertility and genome stability in Brassica allohexaploids.

Synthetic allohexaploid Brassica hybrids (2n = AABBCC) do not exist naturally, but can be synthesized by crosses between diploid and/or allotetraploid Brassica species. Using these hybrids, we aimed to identify how novel allohexaploids restore fertility and normal meiosis after formation. Chromosome inheritance, genome structure, fertility and meiotic behaviour were assessed in three segregating allohexaploid populations derived from the cross (B.

Drought stress has transgenerational effects on seeds and seedlings in winter oilseed rape (Brassica napus L.).

Background: Drought stress has a negative effect on both seed yield and seed quality in Brassica napus (oilseed rape, canola). Here we show that while drought impairs the maternal plant performance, it also increases the vigour of progeny of stressed maternal plants. We investigated the transgenerational influence of abiotic stress by detailed analysis of yield, seed quality, and seedling performance on a growth-related and metabolic level.

Homoeologous exchange is a major cause of gene presence/absence variation in the amphidiploid Brassica napus.

Homoeologous exchanges (HEs) have been shown to generate novel gene combinations and phenotypes in a range of polyploid species. Gene presence/absence variation (PAV) is also a major contributor to genetic diversity. In this study, we show that there is an association between these two events, particularly in recent Brassica napus synthetic accessions, and that these represent a novel source of genetic diversity, which can be captured for the improvement of this important crop species.

Flowering Time Gene Variation in Species Shows Evolutionary Principles.

Flowering time genes have a strong influence on successful reproduction and life cycle adaptation. However, their regulation is highly complex and only well understood in diploid model systems. For crops with a polyploid background from the genus , data on flowering time gene variation are scarce, although indispensable for modern breeding techniques like marker-assisted breeding.

Mapping of homoeologous chromosome exchanges influencing quantitative trait variation in Brassica napus.

Genomic rearrangements arising during polyploidization are an important source of genetic and phenotypic variation in the recent allopolyploid crop Brassica napus. Exchanges among homoeologous chromosomes, due to interhomoeologue pairing, and deletions without compensating homoeologous duplications are observed in both natural B. napus and synthetic B.