*3.4. Gene Structure Analysis*

For the determination of intron and exon numbers and their positions, all the coding and genomic sequences of *TaPAL* members were aligned. The analysis of *TaPAL* genes illustrated variations in exon–intron structure. Nine *TaPAL* genes (*TaPAL3*, *TaPAL5*, *TaPAL8*, *TaPAL18*, *TaPAL24*, *TaPAL27*, *TaPAL35*, *TaPAL36*, and *TaPAL37*) contained no introns in their ORFs (Figure 3). The present findings agreed with the previous studies, which reported that seven *CsPAL* genes contained no intron [26]. Parallel to our results, Vogt [5] also mentioned that none of the nine *ClPAL* genes contained introns. The ORFs of the 26 *TaPAL* genes (*TaPAL1-2*, *TaPAL4*, *TaPAL6-7*, *TaPAL9-12*, *TaPAL14-17*, *TaPAL20-23*, *TaPAL26*, and *TaPAL27-34*) were interrupted by a single intron (length ranged from 99 bp to 138 bp), whereas the intronic length of four genes (*TaPAL28*, *TaPAL32*, *TaPAL26* and *TaPAL30*) varied from 1055 bp to 1618 bp (Figure 3). Dong et al. [25] reported a similar exon–intron pattern in *AtPAL1* and *AtPAL2* [6], and *NtPALl*. Our results also explained that one additional intron was detected in *TaPAL25* and *TaPAL13.* Finally, the length of exon 2 was highly conserved in all the *TaPAL* genes with one intron.

#### *3.5. Gene Ontology of PAL Genes*

For the functional prediction of *PAL*-genes, we conducted GO annotation analysis. In silico functional prediction was carried out and results showed that there were three types of processes involved—biological processes (BPs), molecular processes (MPs), and cellular processes (CPs) (Figure 4). The BPs suggested that *PAL* genes are actively involved in the different metabolic activities and biosynthesis of different organic substances. Furthermore, CPs prediction clarified that almost all the *PAL* genes reside in the cytoplasm and could be involved in regulation of metabolic processes. Meanwhile, MPs showed that *PAL* genes have the enzymatic ability. Such findings clearly indicate that *PAL* genes play role in plant growth by modulating the BPs, MPs, and CPs.
