井冈霉素对水稻纹枯病菌生长发育的影响

Effects of Jinggangmycin on the growth and development of Rhizoctonia solani Kühn causal agent of rice sheath blight

以水稻纹枯病菌(Rhizoctonia solani Kühn)强致病菌株GD-118为供试菌株,在室内观察了井冈霉素(Jinggangmycin)对其生长发育的影响。结果表明:井冈霉素对水稻纹枯病菌的毒力回归方程为y=3.360 3+1.320 4x,相关系数r=0.962 6,理论抑制菌丝生长的EC50为70.2μg/mL,EC95为6 341.5μg/mL。与不加井冈霉素的空白对照相比,用井冈霉素处理后水稻纹枯病菌的菌落边缘明显凹凸不平,边缘菌丝更密集、颜色加深,并且随着井冈霉素处理浓度的增加,菌丝的干质量逐渐降低,但菌落表面菌丝的密集程度有所增加、颜色更深;空白对照的菌核呈颗粒状、褐色,散生于菌落表面,边缘较多而中间较少;用井冈霉素处理后的菌核多数为粉状、浅褐色,部分菌核会连在一起呈块状,分布在菌落外围呈明显的双环形,具不规则的凹凸型菌落边缘,并且随着井冈霉素处理浓度的增加,菌核的干质量有所增加,菌核出现时间比空白对照提前约24h。另外,随着井冈霉素处理浓度的增加,水稻纹枯病菌的菌丝细胞核平均数目和分布范围均有不正常增多的趋势。

The effects of Jinggangmycin on the growth and development of Rhizoctonia solani Kuhn causal agent of rice sheath blight, were investigated by using a virulent isolate GD-118 of R. solani as the test isolate. The results showed that the regression equation for Jinggangmycin toxicity to R. solani was： y=3. 360 3＋1. 320 4x,correlation coefficient r=0. 962 6,the EC50 for theoretical inhibition of mycelial growth was 70. 2 μg/mL, and the EC50 was 6 341.5 μg/mL. In regarding to cultural characteristics and mycelial growth, compared with blank control （without Jinggangmycin）, the colonies of Jinggangmycin treatments had relatively obvious characteristics of uneven edges with more dense mycelia and darkened colour in the plate; with the increase of Jinggangmycin concentrations, the dry weight of mycelia decreased, but the mycelial density on colony surface increased and the colour of colony darkened further. In regarding to sclerotial shape and distribution in the plate, the granular and brown sclerotia scattered on the colony surface of blank control, with more in the periphery and a few in the interior relatively; whereas most sclerotia in Jinggangmycin treatments were powdery, light brown, or a part of the sclerotia coalesced together to form blocks, distributed in the periphery of colony with obvious double rings and anomalous concave or convex edges. In addition, with the increase of Jinggangmycin concentrations,the dry weight of sclerotia increased, the emergence of sclerotia were about 24 h earlier than that of blank control. In regarding to the numbers of mycelial cell nuclei, with the increase of Jinggangmycin concentrations, the numbers of cell nuclei and their distribution in the plate increased abnormally.