*2.1. Sequence Retrieval*

The protein sequences of *Zea mays* HSFs were extracted from PLAZA 4.5 (https: //bioinformatics.psb.ugent.be/plaza/versions/plaza\_v4\_5\_monocots/, accessed on 1 August 2021) and Ensembl Plants (https://plants.ensembl.org/index.html, accessed on 1 August 2021) databases. For this, the BLASTP search was performed using the *Arabidopsis* (AT4G17750, AT2G26150, AT5G03720, AT4G36990, and AT3G24520) and *Zea mays* (GRMZM2G115456, GRMZM2G002131, GRMZM2G086880) HSFs against maize genome Zm-B73-REFERENCE-NAM-5.0, as a query to obtain a putative list of HSFs in the maize genome using default parameters (e-value ≤ <sup>10</sup>−<sup>5</sup> and identity % = 80%). These sequences were checked for the presence of DNA binding domain (DBD) and oligomerization domain (OD) through EMBL-EBI employing the hidden Markov model (HMM) (https://www.ebi.ac.uk/Tools/hmmer/search/phmmer, accessed on 1 August 2021) and SMART (http://smart.embl-heidelberg.de/, accessed on 1 August 2021) tools [47]. The coiled-coil structure, which is a property of OD was predicted using MARCOIL [48]. After carefully analyzing the sequence, the proteins that lacked DBD and/or OD (HR-A/B region) were removed. In addition, the redundant proteins that were the product of a single gene were also discarded from further analysis. Finally, a total of 25 maize HSFs genes were selected for further analysis.

### *2.2. Sequence Analysis*

The coding sequence (CDS) and genomic DNA sequences were obtained from the maize genome database (MaizeGDB) (https://www.maizegdb.org/, accessed on 1 August 2021). The fundamental data such as gene chromosomal location, position, strand position, the total number of transcripts, and intron and exon number was also retrieved from MaizeGDB. The physio-chemical properties of HSFs were predicted using the Expasy website (https://www.expasy.org/, accessed on 1 August 2021). Subcellular localization was predicted using two online tools, i.e., WoLFPSORT [49] and CELLO server.2.5 [50]. The conserved protein domains (through protein sequences) were identified using the MEME suite (https://meme-suite.org/meme/tools/meme, accessed on 1 August 2021) [51]. Twenty conserved motifs were identified using default parameters. Using CDS, the intron–exon structure of maize HSF genes was analyzed through GSDS 2.0 (http://gsds.gao-lab.org/, accessed on 1 August 2021) [52].
