Analysis Of Expression Characteristics Of Potato StAL1 Gene Induced By Ralstonia Solanacearum

Potato(Solanum tuberosum L.)is the third largest food security crop in the world after rice(Oryza sativa)and wheat(Triticum aestivum),and is vital to people's lives.Bactearial wilt(Ralstonia solanacearum species complex,RSSC)is a serious threat to potato cultivation and production.RSSC is a complex species with very fast evolution characteristics,and includes a variety of genotypes of the pathogen.As a soil-borned plant pathogen,RSSC has a great influence on potato industrialization.Therefore,it is necessary to strengthen the breeding of potato resistance to bacterial wilt,especially to study the molecular mechanism of regulating potato bacterial wilt resistance,which plays a great role in increasing grain yield and improving the ability of disease-resistant plants to face adversity.The most direct way is to carry out disease resistance breeding.Therefore,the study of the pathogenic mechanism of plants will provide a new insight for exploring the way of plant disease resistance and stress resistance.Auxilin is an important regulator containing J domain,which plays an important role in clathrin-mediated endocytosis(CME).It has also been reported in most organisms,such as Drosophila melanogaster,Cryptosporidium elegans and yeast.Genes with similar functions of Auxilin have also been found in Arabidopsis thaliana and rice.As a class of J-proteins,Auxilin and Auxilin-like(Auxilin-like)proteins are involved in signal transduction,bacteriostatic defense,resistance to stress and other biological pathways.Auxilin gene is a meshwork protein with neuron-specific regulatory function.In the heat shock protein family,it is a cofactor of Hsc 70(heat shock protein homologue70).Auxilin and Auxilin-like protein(ALP)are mainly involved in CME.In addition,the protein is also involved in cell death regulation,vesicle mediated transport,protein transport and other pathways.More importantly,Auxilin is involved in plant immune response and disease resistance as an immune receptor binding protein.However,as far as we know,there is little research on the function of Auxilin gene in plants,especially in potato.In the early stage of this experiment,it was found that bacterial wilt and plant hormones such as SA could up-regulate the expression of a EST fragment of Auxilin gene in potato.Based on this,the full-length cDNA of a Auxilin gene(named StAL1)in potato was obtained by in silico cloning combined with PCR amplification and sequencing.Bioanalysis of the gene using software showed that the nucleotide was 4 828 bp,the open reading frame was 4 380 bp,and the encoded amino acid was 1 443.The gene was analyzed by qRT-PCR method.The results showed that the expression of StAL1 gene was up-regulated after induced by RSSC and there was a peak value highly expressed within 60 hours after inoculation with RSSC.After chemical treatment with salicylic acid,methyl jasmonate and abscisic acid,the induced expression patterns of each hormone also showed some differences.On the 4th day of salicylic acid treatment,the expression of StAL1 was strongly up-regulated,and the amount of up-regulation was 20 times higher than that of the control and internal reference genes.However,after induced by methyl jasmonate(MeJA)and abscisic acid(ABA),the expression level of StAL1 was not so significant.Among the three tested plants,the expression of StAL1 induced by SA was the most significant.The expression of StAL1 induced by SA and ABA decreased after the peak.In general,the effect of SA on the expression of StAL1 was earlier than that of MeJA.The expression of StAL1 was induced faster and more effectively by SA mechanism,and it was speculated that StAL1 was related to disease resistance.The results of fluorescence in situ hybridization(FISH)showed that the gene was specifically expressed in phloem of vascular bundle system of stem and leaf.The results showed that potato StAL1 gene was involved in the expression process of potato resistance to bacterial wilt,but its detailed induced expression patternand signal pathway needed to be further studied.Combined with the results of this paper,this study will be helpful to further explain the mechanism of StAL1 involved in plant immune response and disease resistance performance,and lay a certain foundation for the research and application of potato bacterial wilt resistance.