Targeted Mutagenesis in Natural Apomicts.

Area of Science:

• Plant reproductive biology
• Genetics and genomics
• Evolutionary biology

Background:

• Apomixis, or clonal reproduction via seeds, is rare (0.1% of species) and evolves independently.
• Identifying apomixis genes is difficult due to polyploidy and low-recombination regions in apomictic plants.
• Previous genetic studies have unraveled the basis of apomixis in only a few plant genera.

Purpose of the Study:

• To identify the specific gene responsible for apomixis in the triploid apomictic dandelion (Taraxacum officinale).
• To investigate the genetic mechanisms underlying apomixis, a form of asexual reproduction through seeds.
• To develop and apply methods for identifying apomixis genes in challenging plant systems.

Main Methods:

• Utilized CRISPR/Cas9 targeted mutagenesis in triploid apomictic dandelions.
• Combined conventional genetic mapping, deletion mapping, and haplotype assembly of apomixis loci.
• Focused on identifying the gene controlling embryogenesis without fertilization.

Main Results:

• Successfully identified the Taraxacum officinale PARTHENOGENESIS (ToPAR) gene.
• The ToPAR gene is confirmed to be responsible for embryogenesis in the absence of fertilization.
• Demonstrated the effectiveness of targeted mutagenesis for apomixis gene discovery.

Conclusions:

• The ToPAR gene is a key factor in apomixis in Taraxacum officinale.
• Targeted mutagenesis is a powerful tool for identifying apomixis genes in polyploid species.
• The methodologies employed can be applied to discover novel apomixis genes in other plant lineages.