Study On The Role Of StBAK1-20 Gene In The Resistance To Ralstonia Solanacearum In Potato

Potato(Solanum tuberosum)is the third largest food crop in the world,however,the yield and quality are threatened by the bacteria Rlastonia solanacearum.Characterization of disease resistance genes is helpful for potato production and industry qualitatively and quantitatively.As a type of transmembrane protein kinase,BAK1 plays an essential role in regulated plant immunity,growth hormone brassinosteroid mediated responses,and cell death containment.With the adjustment of the potato industry and the market,to solve the potato bacterial wilt is essential.Therefore,it has important theoretical significance to study the function of BAK1 in potato defense against R.solanacearum.In the present study,the role of StBAK1-20 gene in the resistance to R.solanacearum in potato was analyzed and results are as follows:(1)Bioinformatics analysis showed that StBAK1-20 gene sequence contains1797 bp and encodes 598 amino acids,including LRRNT domain,4 LRR,Pkinase kinase domain and ATP binding site,belonging to protein kinase family.This gene is located on the plasma membrane,stable hydrophilic transmembrane protein.Analysis of the physical and chemical properties,tertiary structure,evolutionary relationship,conserved domains,promoter elements,expression profiles,protein interactions and GO enrichment of 27 homologous gene sequences showed that the StBAK1-20 gene is involved in plant hormone signaling pathways and adversities stress response.(2)The qRT-PCR method was used to detect the expression characteristics of StBAK1-20 gene under R.solanacearum and hormones(SA,JA,ABA,BR)stress.The results showed that StBAK1-20 gene was rapidly activated and expressed by R.solanacearum.meanwhile,The StBAK1-20 gene is also expressed under the influence of hormones.It is suggested that StBAK1-20 gene is involved in resistance expression and complex hormone signal pathway in potato.(3)The qRT-PCR method was used to detect the expression of StBAK1-20 after BR treatment.It was found that the expression level of StBAK1-20 was negatively correlated with the expression level of the calcium channel gene StCNGC and the pathogenesis related protein encoding gene StPR10 in the JA signaling pathway,and positively correlated with the expression level of pathogenesis related protein coding gene StPR5 in SA signal pathway and pathogenesis related protein coding gene StPR12 in SA/JA signal pathway.The results showed that these co-expressed genes interacted with each other in multiple signal pathways.(4)The resistance function of the indentifer gene Nb BAK1-20 of StBAK1-20 was tested by VIGS method and the resulats suggested that Nb BAK1-20 gene silencing increased the sensitivity of tobacco to R.solanacearum slightly.After treatment with R.solanacearum,the deposition of callose in the leaves of silented tobacco plants was less than that of CK,and the local cell death in leaves was lighter,indicating that StBAK1-20 participated in both PTI immunity and programmed cell death.To some extent,it showed that Nb BAK1-20 gene silencing increased the sensitivity of tobacco to R.solanacearum.(5)Yeast one-hybrid analysis showed that promoter sequence of StBAK1-20 interacted with transcription factors StGATA9,StTGA1 and StWRKY1,on which the transcriptional activation of StBAK1-20 may depend.(6)Yeast two-hybrid technique was used to verify the interaction between StBAK1-20 and BRI1/FLS2.The results showed that StBAK1-20 did not interact directly with BRI1/FLS2.In summary,the StBAK1-20 is involved in the early immune response to R.solanacearum and PTI immunity in potato.These results could provide a theoretical basis for later practical applications in potato resistance breedings.