Polyploidy, or whole genome multiplication, is ubiquitous among angiosperms. Many crop species are relatively recent allopolyploids, resulting from interspecific hybridization and polyploidy.
Thus, an appreciation of the evolutionary consequences of allo polyploidy is central to our understanding of crop plant domestication, agricultural improvement, and the evolution of angiosperms in general. Indeed, many recent insights into plant biology have been gleaned from polyploid crops, including, but not limited to wheat, tobacco, sugarcane, apple, and cotton. A multitude of evolutionary processes affect polyploid genomes, including rapid and substantial genome reorganization, transgressive gene expression alterations, gene fractionation, gene conversion, genome downsizing, and sub- and neofunctionalization of duplicate genes.
- The Southern Middle Class in the Long Nineteenth Century;
- Anthony Trollope and his Contemporaries: A Study in the Theory and Conventions of Mid-Victorian Fiction.
- Crop Science Abstract - REVIEW & INTERPRETATION Polyploidy and Crop Improvement | Digital Library.
In the meantime, we are unraveling the individual and interaction effects of three C chromosomes on the rate and distribution of COs between homologues and testing whether wheat pentaploid AABBD hybrids have the same boosting effect on CO frequencies as Brassica AAC triploid hybrids. The project is proceeding as planned.
Meiotic recombination in polyploid crops: the new challenge
Significant progress has been made on delineating more precisely the regions surrounding PrBn and Ph2. There is an urging demand for new crop ideotypes that not only sustain crop yield, but also improve quality and nutritional value, expand the range of their industrial end-uses and reduce the environmental footprints of crop production.
Gaining control over meiotic COs, which play a pivotal role in generating diversity, is one way to meet all these objectives.
- Project coordinator.
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We therefore predict that CROC will have a significant impact on our fundamental understanding of how CO frequency is controlled, together with the development of strategies for transferring this knowledge to crops so that breeders may take full advantage of traits in other plant varieties or even species. Major international efforts have been made to identify the genes that are involved in meiotic recombination in plants, primarily using diploid Arabidopsis thaliana as model system.
Therefore much of this work has disregarded the consequences of polyploidy, one of the key features of crop plant genomes, on meiotic recombination.
Polyploidy and Hybridization for Crop Improvement
Essential questions thus remain unsolved: How is meiotic recombination regulated in polyploid crop species? Why and how does polyploidy increase the rate of meiotic recombination? How can such improved knowledge on recombination be exploited for crop improvement? We will set up a complete set of integrated analyses to explore many inter-related aspects of CO regulation in polyploid crops. Task 1 aims at characterizing the molecular underpinnings of CO suppression between homeologous chromosomes in wheat and oilseed rape.
We will proceed with positional cloning of the PrBn in oilseed rape and Ph2 in wheat loci. For this latter case, particular emphasis will be placed on evaluating TaMSH7, the most promising candidate for Ph2.
Doubling down on genomes: polyploidy and crop plants.
CROC will thus advance understanding of the mechanisms that hamper the incorporation of beneficial traits from wild relatives into crop plants by promoting a diploid-like meiosis in allopolyploids; overcoming this specific stumbling block would open the road to the creation of new crop varieties resistant to diseases and more efficient in nitrogen use to name only these. Task 2 will advance understanding on the cause of the striking CO rate increase we have discovered in Brassica digenomic triploid AAC hybrid and its possible application to wheat.
We will determine whether these extra COs i arise from one or the other CO pathways and ii can be combined with those resulting from the mutation of an anti-recombination meiotic protein.
We will unravel the individual and interaction effects of three C chromosomes on the rate and distribution of COs between homologues and test whether wheat pentaploid AABBD hybrids have the same boosting effect on CO frequencies as Brassica AAC triploid hybrids. The expected outcomes will pave the way to broaden the genetic variation that is available to plant breeders.
CROC combines a group of researchers with a comprehensive and complementary expertise and set of facilities. Its strong translational emphasis ensures that the results obtained will have general significance that extends beyond oilseed rape and bread wheat. Our work will thus shed new light on the pending cause of CO variation in polyploid plant species, a critical issue for genetics, evolution and plant breeding.
The author of this summary is the project coordinator, who is responsible for the content of this summary.