Protein phosphatase 2C (PP2C) is a negative regulator of serine/threonine residue protein phosphatase and plays an important role in abscisic acid (ABA) and abiotic-stress-mediated signaling pathways in plants. The genome complexity of woodland strawberry and pineapple strawberry is different due to the difference in chromosome ploidy. This study conducted a genome-wide investigation of the FvPP2C (Fragaria vesca) and FaPP2C (Fragaria ananassa) gene family. Fifty-six FvPP2C genes and 228 FaPP2C genes were identified from the woodland strawberry and pineapple strawberry genomes, respectively. FvPP2Cs were distributed on seven chromosomes, and FaPP2Cs were distributed on 28 chromosomes. The size of the FaPP2C gene family was significantly different from that of the FvPP2C gene family, but both FaPP2Cs and FvPP2Cs were localized in the nucleus, cytoplasm, and chloroplast. Phylogenetic analysis revealed that 56 FvPP2Cs and 228 FaPP2Cs could be divided into 11 subfamilies. Collinearity analysis showed that both FvPP2Cs and FaPP2Cs had fragment duplication, and the whole genome duplication was the main cause of PP2C gene abundance in pineapple strawberry. FvPP2Cs mainly underwent purification selection, and there were both purification selection and positive selection effects in the evolution of FaPP2Cs. Cis-acting element analysis found that the PP2C family genes of woodland and pineapple strawberries mainly contained light responsive elements, hormone responsive elements, defense and stress responsive elements, and growth and development-related elements. The results of quantitative real-time PCR (qRT-PCR) showed that the FvPP2C genes showed different expression patterns under ABA, salt, and drought treatment. The expression level of FvPP2C18 was upregulated after stress treatment, which may play a positive regulatory role in ABA signaling and abiotic stress response mechanisms. This study lays a foundation for further investigation on the function of the PP2C gene family.

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The 14-3-3 are highly conserved regulatory proteins found in eukaryotes and play an essential role in plant growth, development and response to stress. However, the evolution of the 14-3-3 gene family in monocotyledons and dicotyledons and the biological functions of the MdGRF13 in abiotic stress remain unknown. In our study, a total of 195 members of the 14-3-3 family were identified from 12 species and divided into ε group and the Non-ε group. Synteny analysis within the 14-3-3 family indicated that segmental duplication events contributed to the expansion of its family. Selective pressure analysis indicated that purifying selection was a vital force in the evolution of 14-3-3 genes, and monocotyledons were found to have lower million years ago (Mya) mean values than dicotyledons. Meanwhile, monocotyledons have a higher codon adaptation index (CAI) and frequency of optical codons (FOP) and a lower effective number of codons (NC) of 14-3-3 genes compared to dicotyledons. Moreover, the yeast two-hybrid demonstrated that MdGRF13 interacts with MdRD22, MdLHP1a and MdMORF1. Significantly, the malondialdehyde (MDA) content and relative electrolyte leakage were decreased, whiles the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were increased in transgenic Arabidopsis than wild type under drought and salt stress. This shows that overexpression of MdGRF13 significantly improved the drought and salt stress in transgenic Arabidopsis. These results provide a theoretical basis for exploring the evolution of the 14-3-3 gene family in monocotyledonous and dicotyledonous and exploring the function of its family.