EjFWLs are repressors of cell division during early fruit morphogenesis of loquat

Abstract

Fruit size varies widely among different loquat species and varieties. While the cell number of fruit is considered as one of the main factors which affect fruit size forming of loquat, the mechanism of variation in fruit size of loquat is still poorly understood. In this work, we aimed to illuminate the functions of EjFWLs in fruit size forming of loquat. Two FWL (tomato FW2.2-like) genes, EjFWL1 and EjFWL2, of loquat were isolated and characterized. Expression analysis showed that transcription levels of both EjFWL1 and EjFWL2 are negatively correlated with that of EjCDKB1;2 in receptacle before bloom. Meanwhile, compared with that in small-fruited loquat varieties, expression of EjFWL1/2 in large-fruited loquat showed a lower level and shorter duration. Ectopic expression of EjFWL1 in tomato inhibited the fruit cell division with reduced ovary and fruit size. Moreover, EjFWLs could interact with EjAGL2 and EjCKIIβ, the proteins which may be involved in the regulation of cell division, respectively. Our data suggested that EjFWLs are cell division repressors and function during early stage of fruit enlargement in loquat.