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Arabidopsis EOD3 homologue PaCYP78A6 affects fruit size and is involved in sweet cherry (Prunus avium L.) fruit ripening

Qi, Xiliang, Liu, Congli, Song, Lulu, Li, Ming
Scientia horticulturae 2019 v.246 pp. 57-67
Arabidopsis, Prunus avium, Prunus padus var. padus, breeding, cytochrome P-450, economic valuation, fruiting, gene overexpression, gene silencing, genes, growth and development, horticulture, mesocarp, mutants, phenotype, ripening, seed size, temperate zones
Sweet cherry (Prunus avium L.) is an important commercial fruit crop cultivated in temperate areas. Fruit size is an influential agronomical trait in the modern horticultural breeding of sweet cherry because it directly affects the plant’s economic value. However, the genetic mechanisms underlying the control of fruit size are largely unknown. Here, we isolated and functionally characterized the sweet cherry cytochrome P450 gene CYP78A6, Arabidopsis EOD3/CYP78A6 homologue gene. Expression profiles showed that PaCYP78A6 was highly expressed in flowers and fruits. Silencing PaCYP78A6 using tobacco rattle virus-induced gene silencing (TRV-VIGS) reduced fruit size by decreasing mesocarp cell volume and expansion during fruit growth and development. In contrast, the overexpression of PaCYP78A6 in Arabidopsis resulted in increased silique and seed sizes, and PaCYP78A6 can recover the phenotype of cyp78a6 mutant. Silencing of PaCYP78A6 delayed fruit ripening and downregulated the ripening-related genes expressed in sweet cherry fruit. Moreover, PaCYP78A6 acts redundantly with PaCYP78A9 to effect fruit size. Thus, PaCYP78A6 appears to regulate the fruit size of sweet cherry during fruit growth and development and is involved in fruit ripening. This work provides new insights into the molecular mechanisms of a gene affecting fruit development and ripening in P. avium.