*3.1. Genome-Wide Identification of BAG Gene Family in Tomato*

The released whole-genome sequences of *Solanum lycopersicum* (ITAG2.4, 3.0, 4.0) were used in the present study. Firstly, we performed a keyword search using the BAG domain file (PF02179) as a query and 10, 14, and 12 genes were obtained from three databases, respectively. Secondly, we searched the genome protein sequence databases ITAG4.0 by BLASTP using seven Arabidopsis (AtBAG) proteins [4], and 11 gene-encoding proteins were identified. After InterProScan search and manual analysis to remove false positive and redundant genes, a total of 10 non-redundant, full-length BAG genes in *Solanum lycopersicum* were identified and designated as *SlBAG1*-*SlBAG10* based on their physical location. Interestingly, there were great differences in the information of the ten *SlBAG* genes in the three databases (Table S2). In order to further confirm the gene information, we cloned the full length of these genes to confirm the CDS sequence. Combining the sequence alignment through the NCBI database, the gene information was finalized (Table 1), which was partly different from the existing ITAG database and the reported characteristics of tomato *SlBAG* genes [24] to some extent. Compared with the BAG gene family reported by [24], there were differences in the genome sequences of eight genes and the coding protein sequences of five genes. In particular, the information of *SlBAG4* was completely different from the existing database. Therefore, we re-analyzed some characteristics of 10 *SlBAG* genes in the following sections.

These *SlBAG* genes were distributed on six chromosomes. *SlBAG1*, *SlBAG4*, and *SlBAG8* were located on chromosome 1, 4, and 10, respectively. Three *SlBAG* genes were on chromosome 6, and the rest were distributed on the other two chromosomes. The relevant characteristics of genes and proteins of SlBAGs were shown in Table 1. The range of coding sequence (CDS) was 513 bp to 3708 bp, and the range of protein was 170 to 1235 amino acids, with an average of 402 amino acids. The molecular weight range of SlBAG protein was 19.43–137.35 kDa and the isoelectric point range was 5.09–10.26.



a: Tomato BAG protein names given in this study; b: gene ID in the ITAG4.0 database; c: gene symbol in NCBI; d: gene characteristics; e: protein characteristics; CDS, coding DNA sequence; AA, amino acid; MW, molecular weight; pI, isoelectric point; kDa, kilodalton.
