Identification and analysis of ovate family proteins in Camellia oleifera

Ovate family proteins (OFPs), part of which are related with fruit shape, are a class of plant-specific transcription factors. Investigation of OFPs is helpful to promote the fruit height and yield of Camellia oleifera. Based on the date of genome, transcriptome and single-cell RNA-seq data, identification and analysis of OFPs were conducted in C. oleifera using bioinformatic approaches. A total of 37 CoOFP genes were identified in the genome data of C. oleifera, and the 37 CoOFP proteins were divided into 4 subfamilies and 7 groups according to the topology of phylogenetic tree. Group II-1, III-1 and IV-1 contained 3, 4 and 11 CoOFP proteins, which were homologues of BnOFP13_2, SlOFP20 and OVATE, respectively. The results of transcriptome expression profiling showed that CoOFP26 of group III-1 expressed in flower bud, pistil, stamen, anther, seed, pericarp and root. CoOFP26 were also detected in placenta (clusters 4 and 11) of mature ovaries. Both of CoOFP23 and CoOFP29 of group IV-1 mainly expressed in flower bud, pistil, stamen, anther, seed and pericarp. CoOFP23 was detected in carpel inner layer (clusters 1 and 8) of mature ovaries. CoOFP29 was also detected in cluster 1. CoOFP26 may be involved in regulation of cell proliferation of placenta and pericarp along proximo-distal axis. Both of CoOFP23 and CoOFP29 may be involved in regulation of cell proliferation of carpel and pericarp along proximo-distal axis. CoOFP23, CoOFP26 and CoOFP29 may be the key genes for regulating the fruit height of C. oleifera.