The MAPKKK gene family in cassava: Genome-wide identification and expression analysis against drought stress

Jianqiu Ye,Hai Yang,Zehong Ding,Wenquan Wang,Haitao Shi,Ying Luo,Kaimian Li,He Zhang,Wei Hu,Weiwei Tie,Ming Peng,Yan Yan,Zhiqiang Xia,Yunxie Wei

doi:10.1038/s41598-017-13988-8

Abstract

Mitogen-activated protein kinase kinase kinases (MAPKKKs), an important unit of MAPK cascade, play crucial roles in plant development and response to various stresses. However, little is known concerning the MAPKKK family in the important subtropical and tropical crop cassava. In this study, 62 MAPKKK genes were identified in the cassava genome, and were classified into 3 subfamilies based on phylogenetic analysis. Most of MAPKKKs in the same subfamily shared similar gene structures and conserved motifs. The comprehensive transcriptome analysis showed that MAPKKK genes participated in tissue development and response to drought stress. Comparative expression profiles revealed that many MAPKKK genes were activated in cultivated varieties SC124 and Arg7 and the function of MeMAPKKKs in drought resistance may be different between SC124/Arg7 and W14. Expression analyses of the 7 selected MeMAPKKK genes showed that most of them were significantly upregulated by osmotic, salt and ABA treatments, whereas slightly induced by H2O2 and cold stresses. Taken together, this study identified candidate MeMAPKKK genes for genetic improvement of abiotic stress resistance and provided new insights into MAPKKK -mediated cassava resistance to drought stress.

Highlights

Mitogen-activated protein kinase kinase kinases (MAPKKKs), an important unit of mitogen-activated protein kinases (MAPKs) cascade, play crucial roles in plant development and response to various stresses
Due to the central role of MAPK cascade in plant development and stress response and the characteristic of drought resistance of cassava, it is necessary to investigate the possible role of MAPKKKs in cassava
Genome-wide analyses have identified many MAPKKKs in various plant species, including 80 members in Arabidopsis[23, 75] in Oryza sativa[24, 71] in Zea mays[25, 89] in Lycopersicon esculentum[26, 59] in Cucumis sativus[27, 150] in Glycine max[28, 45] in Vitis vinifera[31, 73] in Medicago truncatula[29], and 77 in Musa acuminate[30]. This indicated that MAPKKKs in cassava had expanded compared to that in Cucumis sativus and Vitis vinifera, while had shrunk compared to that in Arabidopsis, Oryza sativa, Zea mays, Lycopersicon esculentum, Glycine max, Medicago truncatula, and Musa acuminate

Summary

Introduction

Mitogen-activated protein kinase kinase kinases (MAPKKKs), an important unit of MAPK cascade, play crucial roles in plant development and response to various stresses. Among the stress-activated molecular pathways, mitogen-activated protein kinases (MAPKs) signaling cascade plays central roles in multiple biological processes[1,2]. Some genes related to MAPK cascade pathway are identified to play a vital role in environmental stress responses. MAP3Kd4 plays an important role in increasing salt stress resistance and ABA response by over-expression analysis[11]. The above studies support that MAPK cascade pathway is a crucial regulator of plant development and stress response. Investigation of the gene families related to MAPK cascade is necessary to elucidate the biological processes of cassava development and stress responses

Methods

Results

Conclusion