Abstract
Leaves and flowers are crucial for the growth and development of higher plants. In this study we identified a mutant with narrow leaflets and early flowering (nlef) in an ethyl methanesulfonate-mutagenized population of woodland strawberry (Fragaria vesca) and aimed to identify the candidate gene. Genetic analysis revealed that a single recessive gene, nlef, controlled the mutant phenotype. We found that FvH4_1g25470, which encodes a putative DNA polymerase α with a polymerase and histidinol phosphatase domain (PHP), might be the candidate gene, using bulked segregant analysis with whole-genome sequencing, molecular markers, and cloning analyses. A splice donor site mutation (C to T) at the 5' end of the second intron led to an erroneous splice event that reduced the expression level of the full-length transcript of FvePHP in mutant plants. FvePHP was localized in the nucleus and was highly expressed in leaves. Silencing of FvePHP using the virus-induced gene silencing method resulted in partial developmental defects in strawberry leaves. Overexpression of the FvePHP gene can largely restore the mutant phenotype. The expression levels of FveSEP1, FveSEP3, FveAP1, FveFUL, and FveFT were higher in the mutants than those in 'Yellow Wonder' plants, probably contributing to the early flowering phenotype in mutant plants. Our results indicate that mutation in FvePHP is associated with multiple developmental pathways. These results aid in understanding the role of DNA polymerase in strawberry development.