Recently, a paper titled PaCYP78A9, a Cytochrome P450, Regulates Fruit Size in Sweet Cherry (Prunus avium L.), reported by sweet cherry germplasm improvement research team from Zhengzhou Fruit Research Institute of Chinese Academy of Agricultural Sciences (CAAS), was published on the Frontiers in Plant Sciences. The essential role of PaCYP78A9 controlling the fruit size in P. avium was investigated in this paper.

Sweet cherry (Prunus avium L.) is an important fruit crop in which fruit size is strongly associated with commercial value; few genes associated with fruit size have, however, been identified in sweet cherry. Here, we characterized a P. avium CYP78A gene PaCYP78A9 that is thought to be involved in the regulation of fruit size and organ development using overexpression and silencing approaches. PaCYP78A9 was functionally characterized and found to affect fruit size by influencing mesocarp cell proliferation and expansion during fruit growth and development. The specific transcription pattern of PaCYP78A9 was positively and closely associated with final fruit size and we further used transgenic lines over-expressing or silenced for PaCYP78A9 to show that it is involved in regulating fruit size. These findings provide novel insights into understanding the molecular mechanisms underlying fruit size determination during fruit growth and development in fruit trees.