Current Status of Octoploid Strawberry (Fragaria × ananassa) Genome Study

Abstract

The complex structure of the polyploid genome has inhibited advances in genomics and genetic analysis in polyploid species. Octoploid strawberry (Fragaria × ananassa) is allopolyploidy species (2n = 8x = 56) with an estimated genome size of 1C = 708–720 Mb. The recent study reported by Tennessen et al. (2014) suggested that the genome of F. × ananassa consisted of each one pair of F. vesca-like and Fragaria iinumae-like genomes and two other pairs of subgenomes. Therefore, while the genome sequences of F. vesca have played an important role, the whole genome sequences of F. × ananassa are also essential for a more detailed and thorough understanding in studies about F. × ananassa. The construction of high-quality subgenome-specific reference sequences in F. × ananassa has been a long-dreamt goal, due to its potential for analyzing the expression of previously unexplored genes, such as in the evolution in Fragaria species, and for accelerating molecular breeding. In this chapter, we review the recent results of large-scale genome and transcriptome analyses related to genome sequence dissection in F. × ananassa.