棉疫病菌90kD胞外蛋白激发子生物活性与稳定性研究

 对棉疫病菌(Phytophthora boehmeriae Saw.)90 kD胞外蛋白激发子的生物活性与稳定性进行了研究。用不同浓度的激发子处理烟叶测定其诱发过敏反应的有效浓度,结果是所测定的0.5~100 nmol/L各浓度均可诱发过敏反应,但100 pmol/L不能诱发过敏反应,表明该激发子诱导烟草产生过敏反应的最低有效浓度在100 pmol/L~0.5 nmol/L之间。该激发子可诱导不同烟草(Nicotiana tabacum L.)品种产生过敏反应,但不能诱导辣椒(Capsicum annuum L.)和茄子(Solanum melongena L.)等茄科作物及棉花(Gossypium arboreum Linn.)发生过敏反应,初步表明该激发子诱导植物发生过敏反应具有一定的专化性。以10 nmol/L激发子溶液处理烟叶后分别于第0、24、48和72 h接种烟草疫霉(Phytophthora nicotianae),结果证明该激发子可以诱导烟草产生抗性反应,其抗性以处理后立即接种烟草疫霉为最强,接种后48h防效达68%,以后随时间的延长逐渐减弱。激发子分别经p H值2~14的水溶液25℃处理30 min,或分别经4、25、60和100℃处理5 min仍能诱发过敏反应,但是经蛋白酶K处理后不能诱发过敏反应。表明该激发子对酸、碱和温度不敏感,但对蛋白酶K敏感。

BIOACTIVITY AND STABILITY OF 90 kD EXTRACELLULAR PROTEIN ELICITOR FROM Phytophthora boehmeriae

Bioactivity and stability of purified 90 kD extracellular elicitor protein from Phytophthora boehmeriae were studied. The elicitor could induce hypersensitive responses (HR) on tobacco leaves at different doses ranging from 0.5 nmol/L to 100 nmol/L but not at 100 pmol/L, which indicated that the minimal efficient dosage of inducing HR on tobacco was between 100 pmol/L and 0.5 nmol/L. The elicitor could also induce HR on other cultivars of Nicotiana tabacum butnotonotherSolanaceae (eggplant and pepper)oroncotton(Gossypium arboreum), which suggested that this 90 kD elicitor was host-specific. When the 90 kD elicitor was infiltrated into the tobacco leaves, it could induce the systemic acquired resistance (10%~68%) to P. nicotianae that was inoculated on the tobacco stem. The highest level of induced resistance was acquired when tobacco stems were inoculated immediately after its leaves being treated with elicitor at different pH (pH2 pH14) for 30 minutes or at different temperature (4℃, 25℃, 60℃, 100℃) for 5 minutes, the elicitor could maintain its activity of inducing HR. However,the treatment with proteinase K could cause the loss of its ability of inducing HR in tobacco. Results showed that the elicitor was not sensitive to acid, alkali or temperature, but was sensitive to proteinase K.