大豆疫病抗性遗传分析及多抗资源创新

Phytophthora root rot of soybean is a dangerous disease caused by Phytophthora sojae. It was first found in Indiana of USA in 1948 and was found in Northeast China in 1991. Phytophthora root rot of soybean has become the worldwide disease and has been found in 20 countries. In Heilongjiang, this disease was found province in 34 counties and 5 farm branch bureaus. We began to study this disease from 1996.922 soybean materials from Northeast China and 31 from other counties were analyzed that there are large number of resistance materials in Northeast China. The heredity of resistance in soybean to single race of Phytophthora sojae had the characteristic of quality character. 5 soybean materials resistant to 8 strains of Phytophthora sojae and 2 soybean materials resistant to Phytophthora sojae and 3 other soybean diseases were obtained in this study. In order to utilize the resistant materials effectively, some resistance genes were also analyzed..Physiological races of Phytophthora sojae in China are different to that of USA and 23 soybean materials was chosen as the identified host for the pathogen in China. According the distribution and differentiation of Phytophthora sojae, we get the conclusion that the Phytophthora sojae in China is originated and have began to differentiate further. Soybean plant was infected mainly by zoospore. Study on pathogen isolation, inoculation method and conditions of toxin production may improve the resistance breeding and some other related studies. The morphological and structural study showed that major accumulation sites of zoospores of Phytophthora sojae were in rootlets; meristem and elongation zone of tap root tips, then encysted, and germinated to primary and secondary hypha. When soybean plant was infected, the root shape of smaller rootlet/tap root, turgescent meristem zone of root tips, changes of cell structure of root and stem were observed. The resistance of older plant to Phytophthora sojae was related to the increased activities of SOD, PPO, PAL, PO and the accumulation of phenols and flavonoids. Metabolic pathway of phenylalanine was related to the plant resistance and produced many kinds of secondary metabolic materials against Phytophthora sojae. Phenols in resistant plant could change to more toxicant oxidases by phenoloxidase to resist Phytophthora sojae. This was the defense reaction after metabolic pathway of phenylalanine. Using PO and SOD to clean excess oxygen radical, to avoid the membranous overoxidation, was another defense mechanism in soybean to Phytophthora sojae.

大豆疫霉根腐病已构成东北特别是黑龙江大豆生产中的主要威胁，抗病育种是最经济有效的措施。对优势致病小种的抗感亲本间杂交以及抗性基因聚合重组，再通过鉴定和选择，创造前所未有的抗多小种的资源和亲本，将为抗病育种规律提供理论，同时也为抗性机理和分子生物的研究提供近等基因系等宝贵材料。.