Evolution of the 14-3-3 gene family in monocotyledonous and dicotyledonous and validation of MdGRF13  function in transgenic Arabidopsis thaliana

Abstract 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.