Comparative Transcriptomics of Strawberries (Fragaria spp.) Provides Insights into Evolutionary Patterns

Area of Science:

• Genomics
• Evolutionary Biology
• Plant Science

Background:

• The genus Fragaria (strawberry) offers rich genomic resources for studying speciation and evolution.
• Comparative genomics and evolutionary studies benefit from closely related species with available genome sequences.

Purpose of the Study:

• To reconstruct the phylogenetic tree of Fragaria at the genomic level.
• To investigate the origin and speciation patterns of the Fragaria genus.
• To identify genes associated with fruit domestication and agronomic traits in cultivated strawberries.

Main Methods:

• Generated seven de novo transcriptome sequences for Fragaria species.
• Reconstructed a phylogenetic tree using genomic data from 19 Rosales species.
• Identified positively selected genes in the cultivated strawberry genome (F. × ananassa).

Main Results:

• The phylogenetic tree shows Fragaria grouped with Rubus, with three distinct subclades.
• Evidence suggests Fragaria originated in East Asia around 7.99 million years ago.
• Speciation in Southwest China occurred approximately 3.98 million years ago, linked to environmental changes.
• 510 positively selected genes in cultivated strawberries are enriched in functions related to fruit quality and flavor.

Conclusions:

• The study elucidates evolutionary patterns and speciation mechanisms within the Fragaria genus.
• Identified key genes provide insights into the genetic basis of strawberry fruit domestication.
• Findings contribute to understanding plant evolution and improving cultivated strawberry traits.