Objective  Bioinformatics of YUCCA family encoding the flavin-containing monooxygenase associated with biosynthesis of indole-3-acetic acid (IAA) in passion fruit was studied.

  Methods   Bioinformatic methods were applied to analyze the physicochemical properties, conserved domains, chromosome location, structure, phylogenetic tree, and cis-acting elements of the genes in Passiflora edulis Sims. qRT-PCR was used to determine the expressions of some members under IAA treatment.

  Results   There were 29 YUCCA members unevenly distributed in 8 chromosomes of P. edulis. They significantly differed in length that ranged from 552 bp to 9210 bp and contained 1–8 introns and 8 conserved motifs. A phylogenetic tree analysis divided the family into three distinct categories, and within a same class the members were highly conservative. Genetically, the genes were more closely related to Medicago sativa L. and Arabidopsis thaliana than Oryza sativa L. The cis-acting element analysis indicated that the promoter of the family genes could be induced by various hormones and respond to various stresses. PeYUCCA6, PeYUCCA11, and PeYUCCA16 showed low or no expression in the leaves of Tainong and Golden Passion Fruit, but PeYUCCA23 had a high expression suggesting its predominant role in the plant development. The treatment of 100 μmol·L⁻¹ IAA significantly elevated the expressions of PeYUCCA7, PeYUCCA13, PeYUCCA17, PeYUCCA24, and PeYUCCA26.

  Conclusion  The expressions of YUCCAs in P. edulis varied greatly under IAA treatment. But as a family, the genes likely played an important role in the growth, development, and resistance to adverse environment of passion fruits.