Genome-Wide Identification and Expression Analysis of the PpYUCCA Gene Family in Weeping Peach Trees (Prunus persica ‘Pendula’)

Abstract

Auxin is an important endogenous plant hormone that is usually present as indole-3-acetic acid (IAA). The flavin monooxygenase YUCCA is the rate-limiting enzyme of IAA biosynthesis and plays an important regulatory role in plant growth and development. To further investigate the function of the YUCCA gene family in weeping peach trees, members of the YUCCA gene family were identified via bioinformatics analysis. The gene structure and conserved domains of the weeping peach YUCCA genes were investigated, and phylogenetic analysis and gene annotation were carried out. Fourteen PpYUCCAs were identified in the weeping peach variety ‘Hongchuizhi’ and were found to be randomly located on five different chromosomes. Moreover, the prediction of subcellular localization showed that most of the YUCCA proteins were localized in the cytoplasm. Based on our transcriptome analysis, only nine PpYUCCAs, including PpYUCCA1, PpYUCCA3/4/5/6, PpYUCCA9, and PpYUCCA12/13/14, were expressed in the weeping peach branches, which could result in the accumulation of auxin. PpYUCCA6/12 may play a critical role in the appearance of the weeping trait, as indicated by the higher expression levels found in the Hongchuizhi variety compared with the Xiahui 6 variety. The results of this study provide a foundation for further research on the biological functions of PpYUCCAs in weeping peach trees.