Genome-Wide Identification of the YABBY Gene Family in Orchids and Its Expression Patterns in .

The small plant-specific YABBY gene family plays key roles in diverse developmental processes in plants. , , and are perennial herbaceous plants belonging to Orchidaceae with a high ornamental value. However, the relationships and specific functions of the YABBY genes in the species remain unknown. In this study, six s, nine s, and nine s were identified from the genome databases of the three species, which were unevenly distributed on five, eight, and nine chromosomes, respectively. The 24 YABBY genes were classified into four subfamilies (CRC/DL, INO, YAB2, and FIL/YAB3) based on their phylogenetic analysis. A sequence analysis showed that most of the YABBY proteins contained conserved C2C2 zinc-finger and YABBY domains, while a gene structure analysis revealed that 46% of the total YABBY genes contained seven exons and six introns. All the YABBY genes harbored a large number of Methyl Jasmonate responsive elements, as well as anaerobic induction -acting elements in the promoter regions. Through a collinearity analysis, one, two, and two segmental duplicated gene pairs were identified in the , , and genomes, respectively. The values of these five gene pairs were lower than 0.5, indicating that the YABBY genes underwent negative selection. In addition, an expression analysis revealed that plays a role in ovary and early-stage petal development, while is essential for lip development and is crucial for early sepal formation. primarily regulates sepals during blooming. Furthermore, there is the potential involvement of and in gynostemium development. The results of a comprehensive genome-wide study would provide significant clues for future functional investigations and pattern analyses of YABBY genes in different flower parts during flower development in the species.