Due to DNA heterozygosity and repeat content, assembly of non-model plant genomes is challenging. Herein, we report a high-quality genome reference of one of the oldest known domesticated species, fig (Ficus carica L.), using Pacific Biosciences single-molecule, real-time sequencing. The fig genome is ~333 Mbp in size, of which 80% has been anchored to 13 chromosomes. Genome-wide analysis of N6 -methyladenine and N4 -methylcytosine revealed high methylation levels in both genes and transposable elements, and a prevalence of methylated over non-methylated genes. Furthermore, the characterization of N6 -methyladenine sites led to the identification of ANHGA, a species-specific motif, which is prevalent for both genes and transposable elements. Finally, exploiting the contiguity of the 13 pseudomolecules, we identified 13 putative centromeric regions. The high-quality reference genome and the characterization of methylation profiles, provides an important resource for both fig breeding and for fundamental research into the relationship between epigenetic changes and phenotype, using fig as a model species.
Keywords: Ficus carica L.; N4-methylcytosine; N6-methyladenine; genome assembly; single-molecule real-time sequencing.
© 2019 The Authors The Plant Journal © 2019 John Wiley & Sons Ltd.