Genome-wide characterization and expression profiling of MAPK cascade genes in Salvia miltiorrhiza reveals the function of SmMAPK3 and SmMAPK1 in secondary metabolism

Yongfeng Xie,Pengda Ma,Jie Yang,Meiling Ding,Tianlin Pei,Juane Dong,Bin Zhang

doi:10.1186/s12864-020-07023-w

Abstract

BackgroundThe contribution of mitogen-activated protein kinase (MAPK) cascades to plant growth and development has been widely studied, but this knowledge has not yet been extended to the medicinal plant Salvia miltiorrhiza, which produces a number of pharmacologically active secondary metabolites.ResultsIn this study, we performed a genome-wide survey and identified six MAPKKK kinases (MAPKKKKs), 83 MAPKK kinases (MAPKKKs), nine MAPK kinases (MAPKKs) and 18 MAPKs in the S. miltiorrhiza genome. Within each class of genes, a small number of subfamilies were recognized. A transcriptional analysis revealed differences in the genes’ behaviour with respect to both their site of transcription and their inducibility by elicitors and phytohormones. Two genes were identified as strong candidates for playing roles in phytohormone signalling. A gene-to-metabolite network was constructed based on correlation analysis, highlighting the likely involvement of two of the cascades in the synthesis of two key groups of pharmacologically active secondary metabolites: phenolic acids and tanshinones.ConclusionThe data provide insight into the functional diversification and conservation of MAPK cascades in S. miltiorrhiza.

Highlights

The contribution of mitogen-activated protein kinase (MAPK) cascades to plant growth and development has been widely studied, but this knowledge has not yet been extended to the medicinal plant Salvia miltiorrhiza, which produces a number of pharmacologically active secondary metabolites
The length of the predicted MAPKs ranged from 353 (SmMAPK7) to 690 (SmMAPK10) residues, that of the MAPK kinase (MAPKK) from 289 (SmMAPKK5) to 521 (SmMAPKK3) residues, that of the MAPK kinase kinase (MAPKKK) from 185 (SmMAPKKK49) to 1401 (SmMAPKKK3) residues and that of the MAPK kinase kinase kinase kinase (MAPKKKK) from 456 (SmMAPKKKK6) to 837 (SmMAPKKKK5) residues; the molecular weights in the full set of polypeptides ranged from 32.4 kDa (SmMAPKK5) to 155.3 kDa (SmMAPKKK3), and their pI ranged from 4.49 (SmMAPKKK38) to 9.77 (SmMAPKKK14)
The phylogeny and exon-intron structure of the MAPK cascade genes The alignment of S. miltiorrhiza sequences with those of A. thaliana revealed that the SmMAPKs fell into four subfamilies (A through D), the SmMAPKKs into five subfamilies (A through E), the SmMAPKKKs into three subfamilies (MEKK, ZIK and RAF) and the SmMAPKKKKs into two subfamilies (GCK-III and -VI) (Fig. 1)

Summary

Introduction

The contribution of mitogen-activated protein kinase (MAPK) cascades to plant growth and development has been widely studied, but this knowledge has not yet been extended to the medicinal plant Salvia miltiorrhiza, which produces a number of pharmacologically active secondary metabolites. Mitogen-activated protein kinase (MAPK) cascades are a universal characteristic of eukaryotic cells These cascades involve the activity of four distinct types of kinases: MAP kinases (MAPKs), MAPK kinases (MAPK Ks), MAPKK kinases (MAPKKKs) and MAPKKK kinases (MAPKKKKs) [14,15,16]. The present study takes advantage of the availability of a complete S. miltiorrhiza genome sequence [46] to document the species’ MAPK cascade gene content and was undertaken because these genes are likely important for the synthesis of its bioactive secondary metabolites. Their identification may lead to the application of metabolic engineering with a view to improving the productivity of the S. miltiorrhiza plant

Methods

Results

Discussion

Conclusion