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Summary: Leaves are strikingly diverse in terms of shapes and complexity. The wild and cultivated strawberry plants mostly develop trifoliate compound leaves, yet the underlying genetic basis remains unclear in this important fruit crop in Rosaceae.Here, we identified two EMS mutants designated simple leaf1 (sl1‐1 and sl1‐2) and one natural simple‐leafed mutant monophylla in Fragaria vesca. Their causative mutations all reside in SL1 (FvH4_7g28640) causing premature stop codon at different positions in sl1‐1 and sl1‐2 and an eight‐nucleotide insertion (GTTCATCA) in monophylla.SL1 encodes a transcription regulator with the conserved DNA‐binding domain GT‐1 and the catalytic domain of protein kinases PKc. Expression of SL1pro::SL1 in sl1‐1 completely restored compound leaf formation. The 35S::SL1 lines developed palmate‐like leaves with four or five leaflets at a low penetrance. However, overexpressing the truncated SL1ΔPK caused no phenotypes, probably due to the disruption of homodimerization. SL1 is preferentially expressed at the tips of leaflets and serrations. Moreover, SL1 is closely associated with the auxin pathway and works synergistically with FveLFYa in leaf morphogenesis.Overall, our work uncovered a new type of transcription regulator that promotes compound leaf formation in the woodland strawberry and shed new lights on the diversity of leaf complexity control. [ABSTRACT FROM AUTHOR]

Summary: MicroRNAs (miRNAs) are a kind of short noncoding RNA (20–24 nt), playing versatile roles in plant growth and development. Strawberry generates leaves and flowers with unique features. However, few miRNAs have been functionally characterised in strawberry, especially for their developmental regulation.Here, we identified one ethyl methanesulfonate (EMS) mutant, deeply serrated (des), in the woodland strawberry Fragaria vesca that has wrinkled leaves with deeper serrations, serrated petals and deformed carpels. The causative mutation occurs in the 19th nucleotide of the FvemiR164a mature sequence. Overexpressing FveMIR164A rescued the phenotypes of des/fvemir164a except the petal serrations.Furthermore, we identified two allelic mutants of FveCUC2a, one target of FvemiR164a, which developed leaves with smooth margins and fused leaflets. Phenotypes of the double mutant fvemir164a fvecuc2a indicated that the two genes act linearly in leaf and carpel development, but synergistically in the development of other floral organs and inflorescence architecture.This work demonstrates the conserved and novel roles of the miR164‐CUC2 module in leaf and flower development in different plant species, and reveals that the 19th nucleotide of FvemiR164a is important for its processing. [ABSTRACT FROM AUTHOR]