Studies On Physiological Races Of Pseudomonas Syringae Pv.glycinea

After extensive field investigation and considerable samples collection in China, mainly in Jilin, Liaoning and Heilongjiang provinces, and then pathogenic isolation and purification of bacterial blight of soybean were made. And pathogenic features on soybean (cultivar Jilin 20) were tested. Primary leaves of 10- to 14-day-old plants (primary leaves just fully expanded) were inoculated with water suspensions of bacteria adjusted to IX 108CFU/ml. Suspensions were introduced into the leaves at a pressure of 147kPa. Norm of the susceptible (S) and resistant (R) reactions is : S= compatible combination, typified by water-soaking after 3 days followed by necrosis; R= incompatible hypersensitive resistant reaction with no water-soaking or no reaction. Then the physiological and biochemical characters of the strains were also tested. Finally, 42 strains of Pseudomonas syringae pv. glycinea were defined.According to relative data and field survey, 62 soybean cultivars from colleges and institutes in Northeast China were collected, reactions of 62 soybean cultivars to the 42 strains were tested in the same way pathogenic features on soybean (cultivar Jilin 20 ) were done.After the reaction were repeatedly tested for 3 ~ 5 times, 6 differential hosts, Shishengchangye, Changnong 4, Dandou 4, Zaofeng 3, Jilin 28, and Jinte, were screened. Norm as the differential hosts is: 1. Stability of susceptibility and resistance; 2. Combination of susceptible and resistant cultivars; 3: different cultivars from different areas. Finally the 6 differential hosts consist of identification system.With the system, 42 strains were fallen into 14 physiological races (C1, C2 C3, C4, C5, C6, C7, C8, Q9, C10, C11, C12, C13 & C14). In the same time, distributions of all of the identified races were described in the China, especially in Jilin, Liaoning and Heilongjiang provinces.There are race C2,C3,C4,C5,C6,C7,C8,C9,C10,C11,C12,C13 & C14 in Jilin province; there are race C1, C4, C9, C13 & C14 in Liaoning province; there are race C1, C3, C7, C8, C11, C12, C13 & C14 in Heilongjiang province. Besides the strain PSG547 from Hubei province belongs to racem. Furthermore according to the origin of strains, the race distribution situation in some districts was also confirmed.In Jilin province, there are race C2, C3, C5, C6, C9, C10, C11 & C12 at Changchun district; race C5, C8, C11, C12, C13 & C14 at Jilin district; race C2, C4, C7, C10 & C12 at Siping district. In Liaoning province, there are race C1. C4, C9 & C13 at Tieling district; race C13 & C14 at Shenyang district. In Heilongjiang province, there are race C1,C2,C13& C14 at Suihua district; race C7,C8, C11 & C12 at Haerbin district. The strain PSG547 is from Wuhan district in Hubei province, therefore there is race Cio at this district.The mutual reactions between 6 hosts and 14 races are obvious and stable, and the reactions of 6 hosts can clearly feature 14 races. Meanwhile the strains belonged to these races can be used to divide cultivars into different reaction groups. That is helpful to analyze cultivars' resistant genes, screen and identify races.The 6 hosts are mainly from native cultivars ( Shishengchangye from Japan). Compared with foreign differential hosts (the hosts confirmed by Cross) , they have stronger differential ability. With the 6 hosts, the races from native areas can be more clearly and practically defined, and distribution of races can more conform with practical situations.In this thesis, identification hosts system of Pseudomotias syringae pv. glycinea was first established hi China, and distributions of races were also first confirmed in the varieties of districts. The findings of the research can be used to identify soybean cultivars' resistance and pathogenic physiological differentiation, and they are to be of value in breeding field.