Genetic and genomic characterization of the LOP locus from Pilosella piloselloides subsp. Praealta : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University

Abstract

Apomixis is an asexual way of reproduction leading to the creation of clones of the mother plant. It is controlled by two independent loci in Pilosella piloselloides subsp. Praealta (Hawkweed): LOA (Loss of apomeiosis) and LOP (Loss of parthenogenesis), which are dominant. Apomictic plants develop one extremely competitive genotype and spread it in a colonial strategy. Only a few crops are apomictic; however, the natural creation of clones could considerably speed up the process of plant breeding and quickly stabilize new varieties adapted to climate change. Pilosella is one of the model plants to study apomixis. The purpose of this work was to investigate the LOP locus on a genetic and genomic level to better understand the mechanism of apomictic plants in the hope of applying it to crops. Using a panel of deletion mutants, this study made it possible to define the size of the LOP locus to about 650kb. A sequence of acceptable quality was checked for this locus using BAC isolates. Finally, the PAR gene contained in the locus for parthenogenesis in Taraxacum (dandelion) (Underwood et al., 2020) was sequenced in Pilosella and several species from the Asteraceae family, indicating the level of conservation of the dominant allele compared to the recessive alleles.