*2.1. Identification of MAPK Family Genes in Kiwifruit*

To identify MAPK family genes from the *A. chinensis* genome, both Hidden Markov Model (HMM) and BLAST searches were performed using *Arabidopsis* and *Vitis. vinifera* MAPK proteins as query sequences. The comparison of the sequence of candidate proteins from BLAST and HMM hits were completed and 25 AcMAPK proteins were identified with top hits for *AtMAPK* and *VvMAPK* orthologs with an e-value cutoff of 1 × e <sup>−</sup>50. Then, some sequences were excluded because they encode very short polypeptides of amino acids, or did not contain the known conserved motifs of the MAPK family proteins by phylogenetic and conserved domains analysis. After multiple steps of screening and validation of the conserved domains, we finally identified 18 putative *AcMAPK* genes and the AcMAPK proteins were named according to the Gene ID number from the *A. chinensis* genome, designated as AcMAPK1–AcMAPK18 (Table 1), which was further supported by multiple sequence alignment analyses (Figure S1). The sequence data of all above *MAPK* genes are shown in Supplementary Material File 1. These putative *AcMAPK* genes were predicted to encode 336 (AcMAPK9) to 1056 (AcMAPK6) amino acids in length, with putative molecular weights (Mw) ranging from 38.82 kDa (AcMAPK12) to 119.46 kDa (AcMAPK6), and protein isoelectric points (pIs) ranging from 4.52 (AcMAPK11) to 9.82 (AcMAPK13). The subcellular localization was predicated and the putative AcMAPKs were located in the cytoplasm, nucleus, and chloroplast, except for AcMAPK9 and AcMAPK11, which were present in the peroxisome and vacuolar, respectively (Table 1).


**Table 1.** The characteristics of putative *MAPK* genes in kiwifruit.

The multiple sequence alignment data showed that all the putative AcMAPKs contain the classical TXY motif (Figure S1), which is located in the activation loop [6]. Moreover, MAPKs have a common docking (CD) domain that was observed in the extended C-terminal region, which is defined as (LH [D/E] XX [D/E] EPXC) and functions as a docking site for MAPKKs. Altogether, we identified 18 *MAPK* genes in kiwifruit.

To determine the chromosomal distribution of the identified AcMAPKs, the physical locations of the sequences of the 18 *AcMAPK* genes on the kiwifruit chromosomes were investigated. As shown in the location image (Figure S2 and Table 1), 18 genes were mapped on 11 chromosomes (including unknown chromosomes). Chromosomes 2, 11, 20, 23, 28, and 29 only contained one gene: *AcMAPK16*, *AcMAPK2*, *AcMAPK6*, *AcMAPK5*, *AcMAPK3*, and *AcMAPK14*, respectively. Chromosomes 13, 15, and 25 contained two genes, Chromosomes 1, and unknown contained three genes, respectively.
