Molecular Evolution,Expansion And Functional Analysis Of Protein Phosphatase 2C In Zea Mays And Glycine Max

The protein phosphatase 2C（PP2C）,catalyzing protein dephosphorylation,can regulate growth and development processes,and respond to multiple stresses in plants.Maize（Zea mays）and soybean（Glycine max）are the important economic and food crops.In the current research,the comprehensive understanding of the PP2C family about the evolution and expansion is still lacking in maize and soybean.This study provides a comprehensive analysis of molecular evolution,molecular expansion,and function of the PP2C family in maize and soybean to illustrate the evolutionary history of the Zm PP2C and Gm PP2C members.In this study,97 Zm PP2Cs were identified in maize,which were further divided into 10 subfamilies.Through the analysis of the PP2C family in other monocots,the Zm PP2C subfamilies displayed biased subfamily molecular evolution and lineage-specific expansion,as evidenced by their differing numbers of member genes,expansion and evolutionary rates,conserved subdomains,chromosomal distributions,expression levels,responsive-regulatory elements and regulatory networks.Moreover,while segmental duplication events have caused the primary expansion of the Zm PP2Cs,the majority of their diversification occurred following the additional whole-genome duplication that took place after the divergence of maize and sorghum（Sorghum bicolor）.After this event,the PP2C subfamilies showed asymmetric evolutionary rates,with the D,F₂ and H subfamily likely the most closely to resemble its ancestral subfamily’s genes.134 Gm PP2C members were identified in soybean,In Gm PP2C family,different subfamilies have different gene proportions,conserved motifs,expansion rates,gene retention rates,evolution rates,response regulatory elements,and expression patterns.In addition,the duplication event is particularly prominent in the Gm PP2C family,and all of the duplicated gene pairs involved the segmental duplication events.The legume-common duplication event and soybean-specific tetraploid have primarily led to the expansion of Gm PP2C members in soybean.Sub-functionalization was the main evolutionary fate of duplicated Gm PP2C members.Meanwhile,massive genes were lost in the Gm PP2C family,especially from the F subfamily.Moreover,the evolutionary rate was slower in the Gm PP2C duplicated genes than other genes,and the WRKY family directly or indirectly affected the evolution of Gm PP2C.The PP2C members,especially members from the H subfamily,are similar to their ancestral genes.This study provides novel insights into the molecular evolution and expansion of the PP2C family in maize and soybean.Our findings also enhance our understanding of molecular evolution and functional analysis in the PP2C family,and lay the foundation for the functional analysis of Zm PP2Cs and Gm PP2Cs.Besides,some putative candidate genes were provided in the maize and soybean breeding.