Research On The Mechanism Of Wheat Defense Responses At Early Infection Stage Of Puccinia Triticina

In this paper, it set wheat (Triticum aestvum L) Lovrin 10 and Puccinia triticina physiological race 165 as compatible combinations and Lovrin 10 and physiological race 260 as incompatible combinations, and studied the formation of the early-stage infection structure of Puccinia triticina in different compatible combinations. The germination rates of Puccinia triticina spores of different compatible combinations and their germ tube lengths 2h, 4h, and 6h after inoculation and the number of infection points 8h, 10h and 12h later were recorded and calculated by statistic analysis. The results showed that significant differences were observed 4-6h after inoculation; 8-12h later, the number of infection points in incompatible combinations was significantly less than that in compatible combinations and the differences were extremely significant. These preliminarily proved that the developments of infection structures of different compatible combinations differed greatly.To further confirm the reason of these differences, the induction of disease resistance of Puccinia triticina physiological races to wheat leaves was studied. It first inoculated physiological race 260 in Lovrin 10, and then washed it down 4 hours later and inoculated 165. The development and infection of 165 was inhibited. It showed that inoculating 260 might induce resistance of Lovrin 10 to compatible race and this resistance could directly inhibit the development of Puccinia triticina.Based on previous studies, it is believed thatβ-1,3-glucanase played an important role in this early-stage resistance induction. The intercellular washing fluids (IWF) of leaves inoculated Puccinia triticina were extracted and theβ-1,3-glucanase in them was tested by western-blotting technology. It was found that the content of this enzyme was really high 4 hours after inoculation in incompatible combinations, which was relatively lower in the compatible combinations and in the control combinations. The activity of this enzyme was tested and proved quite high 4 hours after inoculation in incompatible combinations. The product of this enzyme to puccinia triticinia germ tube was also tested by DNS method and it proved that this product is a reducing sugar. According to the tests above,β-1,3-glucanase might played an important role in induction of the early-stage defense response of wheat to Puccinia triticina. In summary, in the interaction of wheat and Puccinia triticina, the formation of the early-stage infection structure of Puccinia triticina in different compatible combinations differed greatly; in incompatible combinations the growths of the germination and the germ tube of the Puccinia triticina and the formation of the stoma vesicle was inhibited by different levels, which might be related to the early-stage resistance of the host—the high content ofβ-1,3-glucanase. This research can provide a basis to further study of the early identification mechanism of the interaction of wheat and Puccinia triticina and the early defense mechanism of wheat to Puccinia triticina.