Analysis Of Defense Response Genes Expression Characteristics In Different Timepoints Of Wheat Roots Infected By Heterodera Filipjevi

Heterodera filipjevi is a kind of important pathogenic nematodes of the world's cereal crop production,which causes substantial losses in wheat production worldwide.In recent years,H.filipjevi parasitism become more and more severe in China with the development of agricultural intensification and mechanization,and it is necessary to reinforce the study on the mechanism of interaction between the pest and host.So far,little is known about the molecular mechanism concerning the H.filipjevi parasitism.In the present study,q RT-PCR analyses were conducted by using two resistant varieties and one susceptible variety,and the gene expression characteristics during infection by Heterodera filipjevi were analyzed,the results are as following:Comparison of inoculation methods for Heterodera filipjevi.1)Two inoculation methods(Shallow plate method and PVC tube method)were used to inoculate Heterodera filipjevi,and the process of infection were observed from the1 st day to 9th day.The results showed shallow plate method is more effective the PVC tube method.Large number of cereal cyst nematode can be observed in both resistant varieties and susceptible variety in the 2nd day by using the shallow plate method,compared with the limited number of cereal cyst nematode by PVC tube method.However,the number of cereal cyst nematode is less in resistant varieties compared with susceptible variety.2)Microscopic observation of infection with cereal cyst nematode in wheat roots.The infection process of cereal cyst nematode was observed in wheat root of both resistant variety and susceptible variety.In the susceptible variety,cereal cyst nematode was observed in the epidermal layer of root the 1st day after inoculation,then began to move to pericycle the 2nd day after inoculation and arrived at pericycle the 5th day after inoculation.While in resistant variety,cereal cyst nematode began to move to pericycle the 5th day after inoculation,which inflected that the moving speed of cereal cyst nematode was slow in resistant variety compared it with susceptible variety.3)The expression patterns of ten genes that may relate to resistance to disease in literatures were analyzed in both resistant varieties and susceptible variety.The results show that the CV767657 belonging to defense response genes the pattern of down-regulation of inoculation Heterodera filipjevi was observed in resistant variety,and higher expression in susceptible variety than resistant varieties.Another gene(i.e.,AK330737)showed expression at early stage in resistant variety,while showed higher expression at late stage in susceptible variety than resistant variety,which imply AK330737 may involve in the resistance to Heterodera filipjevi in wheat.Similar result was also observed for gene EU665453,the function of this gene is similar to WRKY transcription factor,higher expression in the 7st day and 9st day susceptible variety than resistant varieties after inoculated by Heterodera filipjevi.The changes of expression pattern were also observed for other genes after inoculation with Heterodera filipjevi.