Identification And Location Of Resistance Gene Against Bacterial Brown Spot Disease In Maize

Maize bacterial brown spot disease is caused by the infection of Pseudomonas syringae pv.syringae Van Holl. There is no report on cell and molecular genetics of this disease up to now. A Fg recombinant inbred lines (RILs) population which was constructed by the descendent of F349 (immune inbred line) and P25 (susceptible inbred line),as materials accompanied by the method of quantitative heredity, was used to study the heredity of resistance to this disease. The resistant-susceptible pools was constructed by choose the extremely resistant and susceptible plants and the technique of SSR was applied to select the molecular markers which revealed the difference between the parents. After obtaining the linkage maker, the study of linkage analysis and gene location using RILs was made. Besides, a genetic map was constructed in the vicinity of the resistant gene. The results obtained from this study provide a basis for isolating the resistant gene and studying its function. The main results are as follows.1. According to the symptoms and morphology of pathogeny, determined that the disease infested on the susceptible inbred line P25 was bacterial brown spot disease, and the pathogeny was Pseudomonas syringae pv.syringae Van Holl.2. Worked out the methods to evaluate incidence. According to the resistant analysis of the field investigation and X examination, proved that the genetic mechanism was in accordant with Mendelian monogene segregation law. Appearances in F9 families was consistent with F8 families. Associated with F1 field behavior, proved that the resistant character is controlled by dominant monogene.3.2 out of 640 SSR markers which distribute on the whole genome showed polymorphic between resistant and susceptible pools.These are umc2409 and bnlg1318, respectively. Moreover, all two makers were located on 4.01-4.02 site of chromosome 4. The name of this gene temporarily nominated is Psy01-F349.4. One resistant gene to bacterial brown spot disease was mapped on chromosome 4, and thedistance to umc2409 and bnlg1318 is 7.6 and 12.2cM, respectively.