Taking HDAC-inhibitors to the next level in DH embryo production
Doubled-haploid (DH) embryo production is a tissue culture technique that is used by all major plant breeding companies to accelerate the plant breeding process. DH production relies on the ability of haploid male (pollen) or female (embryo sac) reproductive cells to regenerate in vitro into an embryo in the absence of fertilization. The haploid embryos or seedlings that are produced can be converted in a single generation into homozygous (double-haploid plants) by spontaneous or induced chromosome doubling, a process that would normally take seven to eight generations of conventional breeding. Manipulation of tissue culture conditions is generally the key factor leading to the development of efficient DH production protocols, however this approach is not always successful and many agriculturally-important crops remain recalcitrant for DH production.
We have shown that chemical inhibitors of histone deacetylases (HDACs) are potent inducers of haploid embryo development. HDACs epigenetically repress gene expression through histone deacetylation. This project aims to understand the how HDACs prevent haploid cells from becoming embryos and how HDAC inhibitors (HDACi) relieve this repression and direct non-embryogenic cells toward embryogenic growth.
The projects results are intended for professional plant breeding companies. There are four partners in the project: Enza Zaden, Syngenta, BASF Vegetable Seed and Vilmorin & Cie.
This project contributes to the MMIP and Key Technology 2 (ST2) ‘Biotechnology and Breeding’, specifically Mission 44 ‘Generic Key Technologies’. This proposal aims to develop ‘innovative breeding methods’ for haploid breeding, one of the sub-themes within this priority. The project will deliver new generic chemical biology tools for haploid breeding in crops. The technologies developed in this project will accelerate plant breeding by avoiding the need for lengthy classical breeding pipelines
MMIP Mission 44 aims to develop innovative ‘haploid’ breeding methods. The main goal of this project is to optimize and broaden the scope of in vitro haploid breeding methods using known compounds that target epigenetic processes and by understanding the mode of action of these compounds.
The following results are foreseen:
1. Identification of loci-specific histone acetylation marks and gene expression changes that are associated with haploid embryo induction from pollen grains in B. napus.
2. Identification of the arabidopsis and B. napus HDAC proteins that prevent pollen grains from becoming embryos.
3. Identification of arabidopsis HDAC protein complex components that prevent pollen grains from becoming embryos.
3. Improved HDACi-induced haploid embryogenesis in crops.