Analyse The Cotton MAPKs Gene Families And The Roles Of MAPK Family Members In The Defense Of Verticillium Wilt Disease

As a conservative protein kinase signal cascades system in eukaryotes, MAP kinase(mitogen-activated protein kinase) signal cascades pathway plays important roles in regulating of plants development and responding to various biotic or abiotic stress signals. This MAP kinase cascade signaling system(MAPKs) is consisted of MAPKKK, MAPKK and MAPK, through sequential phosphorylation. However, it is still unclear the information about MAPK family members in cotton, which are downstream kinases of MAPKs signal cascades, let alone to understand their roles in the defense of cotton verticillium wilt disease. Based on the reported cotton genome data of Gossypium raimondii and Gossypium arboreum, and collected sequences of Gossypium hirsutum MAPK in NCBI, phylogenetic analysis was performed on these cotton MAPK family members through homologous comparison. Results showed that the cotton MAPK gene family contains the TEY phosphorylation sites or TDY phosphorylation sites, and can be divided into 4 subfamilies(groups A, B, C and D) according to the amino acid sequences, the TEY subtype can be classified into three Groups, A, B and C, whereas the TDY subtype forms a more distant Group D. Cotton MAPKK gene family has the characteristic of conservative area S/T-X5-S/T and the active site motif D(I/L/V)K, it also can be divided into 4 subfamilies(groups A, B, C and D) according to its amino acid sequences. Cotton MAPKKK gene family contains MEKK characteristic conservative region G(T/S)PX(W/Y)MAPEV and Raf conservative area GTXX(W/Y)MAPE(L/V), then this MAPKKK gene family falls into two main classes: MEKK and Raf.In addition, we selected some genes from each group in the MAPK family randomly. For A group, we chose ADI52626.1G.hirsutum, Gorai.3g139900.1, ADT65136.1G.hirsutum and Gorai.5g011100.1. For B group, we chose Gorai.1g158800.5, Gorai.1g158800.1, A 32714 and ADI52627.1G.hirsutum. For C group, we chose ABA00652.1G.hirsutum, Gorai.5g109500.1, Gorai.7g050000.1 and ADI52622.1G.hirsutum. For D group, we chose ADI52623.1G.hirsutum, A 01430, A 37089, A 25334, A 24541, A 22593, AHW85276.1G.hirsutum, AET36534.1G.hirsutum, A 22570 and A 07602. And furthermore, the roles of cotton MAPK genes in the defense of cotton verticillium wilt disease were performed by virus induced gene silencing(VIGS) technique. The results showed that, after the gene ADI52623.1G.hirsutum(D) ? A 01430(D) ? A 37089(D) ? A 25334(D) ? A 24541(D) ? AET36534.1G.hirsutum(D) ?ADI52627.1G.hirsutum(B) ? ADI52626.1G.hirsutum(A) and Gorai.3g139900.1(A) were silenced, their resistance to the verticillium wilt of cotton was not obvious; moreover, the gene AHW85276.1G.hirsutum(D)?A 22593(D)?A 07602(D)?A 22570(D)?Gorai.7g050000.1(C)?ADI52622.1G.hirsutum(C)?Gorai.5g109500.1(C)?ABA00652.1G.hirsutum(C)?Gorai.1g158800.5(B)?Gorai.1g158800.1(B) ? A 32714(B) ? ADT65136.1G.hirsutum(A) and Gorai.5g011100.1(A) were silenced, their performance to cotton verticillium wilt is more sensitive, also it showed that this signal transduction pathway by the thirteen MAPK genes regulated may plays an important role in the cotton verticillium wilt. These basic work is expected to expand the study about the cotton signal pathways in the defense of verticillium wilt disease.