*2.1. Retrieval of Protein Sequences Containing the PAL Gene Family in Triticum aestivum*

Two methods were applied to retrieve the phenylalanine ammonia-lyase (PAL) domaincontaining sequences in wheat. The first method searched the *PAL* gene family members in the *Triticum aestivum* by inputting the keywords "Phenyl ammonium lyase (PAL)" in the Ensembl plants database (http://plants.ensembl.org/Triticum\_aestivum/ (accessed on 16 March 2021) [28], while in the second method, the search for wheat *PAL* genes was conducted using *Arabidopsis thaliana PAL* genes (*At3g53260*, *At2g37040*, *At3g10340*, and *At5g04230*) as reference/query to BLASTP [29] against wheat protein database International Wheat Genome Sequencing Consortium (IWGSC) (V2.1), and *Triticum aestivum* chromosome 3B RELEASE 1.0 (http://wheat-urgi.versailles.inra.fr/, accessed on 16 April 2021). Based on more than 75% sequence identity and E-value ≤ 1e-10, the wheat *PAL* gene family was identified. Unique non-redundant wheat PAL gene family members were identified by performing multiple sequence alignments using the ClustalW tool [30], and redundant gene sequences were removed. Further, the Pfam [31] and SMART (http://smart.embl-heidelberg.de/, accessed on 18 May 2021) databases [32] were used for the identification and confirmation of PAL-conserved domains.
