Plant Immune-Cliciting Protein Hpa1 Promotes Cucumber Growth And Disease Resistance

There are many kinds of cucumber diseases,mainly including brown spot,downy mildew,bacterial angular leaf spot,leaf blight,anthracnose,damping-off,blight,blight,gray mold,target spot,powdery mildew and other diseases The disease has the characteristics of fierce coming,fast spreading,severe disease,high incidence and large loss,which has seriously harmed agricultural production and brought serious threats to the yield and quality of cucumber.Harpin protein is a type of protein secreted by the type III secretion system of Gram-negative bacteria that can stimulate multiple signal pathways in plants.It can stimulate the plant’s own immune defense response and induce plant systemic resistance;it can also act on plant growth.Genes promote plant growth and development,and have good application prospects and development space.In previous studies,harpin protein can play a role in the resistance of various plants to diseases.External application of harpin protein can significantly increase the resistance of rice to bacterial blight and rice blast,and increase the resistance of wheat to scab and Improve tomato fruit setting rate and so on.This research aims to study the application of Hpa1 and Hpa1_10-42protein on cucumber disease control and cucumber growth and development by spraying Hpa1 and Hpa1_10-42protein liquid preparations.It is of great significance to cucumber planting and disease control in agricultural production,and it is a green ecology.Agricultural development provides important theoretical and technical support.In this study,cucumber was used as the test object.The Hpa1 and Hpa1_10-42disease resistance and growth promotion tests were carried out indoors and in the field.In the early stage of the study,the seed soaking test found that compared with the control group,the root length and plant length of the Hpa1 and Hpa1_10-42treatment groups were The plant height and the expression of growth genes Cs EIN5,Cs EXP1 and Cs EXP2 of the seedlings sprayed during the vegetative growth period were significantly higher than those of the control group,indicating that Hpa1 and Hpa1_10-42can induce the growth of related genes.The increase in expression level promotes the growth of cucumbers;by observing the flowering transition phenotype and quantitative analysis methods,it is found that the cucumbers treated with Hpa1and Hpa1_10-42show early flowering.The reason is that Hpa1 and Hpa1_10-42induce flowering regulation.The genes Cs FD,Cs FT,and Cs AP1 expression increased.Next,we inoculated Fusarium oxysporum cucumber-specialized bacteria,and using phenotypic observation and quantitative analysis methods,we found that the cucumbers treated with Hpa1 and Hpa1_10-42and the control group Compared with the disease-resistant phenotype,the lowest incidence index of Hpa1_10-42protein is 42.5,and the control effect is about 47.69%.The incidence index of Hpa1 protein treatment is 47.5,and the control effect is about 41.54%.Fluorescence quantitative results show that cucumber The expression of disease resistance-related genes Cs PR1 and Cs NPR1 also increased significantly,indicating that Hpa1 and Hpa1_10-42can increase cucumber disease resistance by inducing an increase in the expression of Cs PR1 and Cs NPR1.In order to determine the application value of Hpa1 and Hpa1_10-42protein preparations,we conducted a disease resistance and growth promotion test on cucumbers in the field.The results showed that the Hpa1_10-42protein-treated plants are in terms of fruit number per plant,average fruit weight and yield per plant.Both were higher than the control and Hpa1 protein treatment plants,the yield increased by 36.67%compared with the control,and the Hpa1protein treatment plant yield increased by 25.32%compared with the control.By measuring the photosynthetic rate of the plants,it was found that the photosynthesis of the plants treated with Hpa1_10-42and Hpa1 was enhanced,indicating that Hpa1 and Hpa1_10-42proteins can induce cucumber seed germination,promote growth and development and increase yield.For the resistance test of cucumber target spot disease in the field,the results showed that the disease index of plants sprayed with Hpa1_10-42and Hpa1 protein preparations was significantly lower than that of the control.Among them,the disease index of Hpa1_10-42protein was the lowest at 45,and the control effect was about 35.71.%,the incidence index of Hpa1 protein treatment was 50.83,and the control effect was about 27.38%.Through the experiments of Hpa1 and Hpa1_10-42protein on cucumber growth and cucumber disease defense under laboratory conditions and in the natural environment of the field,the suitable conditions for the application of Hpa1 and Hpa1_10-42protein in cucumber planting are explored,whether it is It has made a major breakthrough in the yield and quality of cucumber planting in agricultural production,and also has important technical and theoretical support for biopharmaceuticals,making important contributions to the development of ecological agriculture in the future.