EjFRI, FRIGIDA ( FRI ) Ortholog from Eriobotrya japonica , Delays Flowering in Arabidopsis

In the model species , ( ) is a key regulator of flowering time and can inhibit flowering without vernalization. However, little information is available on the function in the Rosaceae family. Loquat ( ) belongs to the family Rosaceae and is a distinctive species, in which flowering can be induced without vernalization, followed by blooming in late-autumn or winter. To investigate the functional roles of orthologs in this non-vernalization species, we isolated an ortholog, dubbed as , from loquat. Analyses of the phylogenetic tree and protein sequence alignment showed that EjFRI is assigned to eurosids I FRI lineage. Expression analysis revealed that the highest expression level of was after flower initiation. Meanwhile, was widely expressed in different tissues. Subcellular localization of EjFRI was only detected to be in the nucleus. Ectopic expression of in wild-type Arabidopsis delayed flowering time. The expression levels of in transgenic wild-type Arabidopsis were significantly higher than those of nontransgenic wild-type lines. However, the expression levels of showed no significant difference between transgenic and nontransgenic wild-type lines. Furthermore, the upregulated expression in the transgenic lines indicated that functioned similarly to the of the model plant Arabidopsis. Our study provides a foundation to further explore the characterization of , and also contributes to illuminating the molecular mechanism about flowering in loquat.