云南半帚孢毒素及其基本性质研究

云南半帚孢 (Leptographiumyunnanense)是云南松纵坑切梢小蠹携带的一种主要的病原性伴生真菌 .以PD培养液对该菌进行培养 ,培养滤液即毒素原液中蛋白部分具致病活性 ,在冷藏及室温条件下 ,该毒素能较长时间 (2 0～ 40d)保持致病活性 (即能在寄主树木上形成一定长度的韧皮反应区 ) ,随着温度的升高 ,其活性逐渐丧失 ;在 6 0℃时 ,该毒素仍可保持一定的活性 ,而在超过 80℃时 ,则完全丧失其活性 .毒素原液pH值为 5 1,渗透势为 - 12 0kPa ,经试验确定毒素原液的毒性非溶液的酸度或渗透势所致 ,从而表明该菌培养液中存在具致病活性的毒素物质 .

Determination and basic properties about the pathogenic toxin of Leptographium yunnanense,a blue-stain fungus associated with Tomicus piniperda

Leptographium yunnanense is the main pathogenic fungus associated with Tomicus piniperda attacking Pinus yunnanensis, which can assist the beetles in overcoming the resistance of the host tree. The fungus could produce pathogenic toxin when it was cultured in PD liquid medium for 30 days. The protein part of the original toxin liquid possesses the pathogenic activity. The toxin could keep its activity for 20 to 40 d under the coolstorage or room temperature. With the increase of temperature, its activity losed gradually. At the temperature of 60℃, the pathogenic toxin could still keep some activities, but losed fully when the temperature exceeded 80℃. The pH value and the osmotic potential of the toxin extraction liquid were 5.1 and -120 kPa,the toxicity of the extract liquid wasn't induced by pH value and osmotic potential of itself. It is indicated that there are pathogenic toxin substances in the extract liquid.