戊唑醇对赤霉病菌生长发育影响的细胞学和免疫细胞化学研究

CYTOLOGY AND IMMUNO-CYTOCHEMISTRY STUDIES OF EFFECTS OF TEBUCONAZOLE ON WHEAT HEAD BLIGHT PATHOGEN IN VITRO

本文采用电子显微镜和免疫细胞化学技术研究了三唑类杀菌剂戊唑醇 (Tebuconazole) 对小麦赤霉病菌Fusarium graminearum菌丝的形态结构、细胞壁成份和毒素产生的影响。结果表明,戊唑醇不但强烈抑制了培养基上菌丝的生长,而且可引起菌丝形态和结构的明显畸形。电镜观察发现,药剂处理后菌丝呈现不规则的肿胀、过度分枝;菌丝细胞壁不规则加厚,尤其是菌丝顶端部位加厚明显;菌丝形成的不完整隔膜增多,且隔膜壁不规则增厚;菌丝细胞内液泡增加、脂肪粒累积,细胞器排列紊乱,原生质最终坏死。有时在坏死菌丝内可发现新的子菌丝,但子菌丝细胞壁不规则加厚、细胞质坏死、也呈不正常状态,并可再度形成新的菌丝。免疫细胞化学标记表明,药剂处理后菌丝细胞中毒素的标记密度明显低于对照菌丝,表明毒素的产生受到了抑制;而菌丝细胞壁的主要成份几丁质和-1,3-葡聚糖的标记密度明显高于对照处理,表明药剂处理可引起菌丝细胞壁中几丁质和-1,3-葡聚糖的过度累积。

The effects of tebuconazole, a triazol group fungicide, were examined on morphology, structure, cell wall components and toxin production of Fusarium graminearum in vitro by means of electron microscopy and cytochemical labeling techniques. The results revealed that tebuconazole not only inhibited hyphal growth of F. graminearum, but also caused a series of marked morphological and structural alterations of hyphae. These changes included irregular swelling and excessive branching of the hyphae, considerable thickening of the hyphal cell walls, particularly at the hyphal tip region, increasing vacuoles and lipoids, very frequent septation with malformed septa and necrosis or degeneration of the hyphal cytoplasm. The formations of new structures like non-membraneous inclusion bodies and new hyphae (daughter hyphae) inside of the collapsed hyphal cells were often detected in the cytoplasm of fungicide-treated hyphae. However, the daughter hyphae also showed abnormal alterations such as irregular thickenings of the cell walls, necrosis of the cytoplasm and formation of new daughter hyphae. Furthermore, immunocytochemical labeling revealed that the labeling density for the toxin in the fungicide-treated hyphae was markedly lower as compared to the control hyphae. but the labeling densities of the chitin and -l, 3-glucan were higher in the cell walls of the fungicide-treated hyphae than in the control hyphae, indicating an excessive accumulation of chitin and ?l, 3-glucan in the cell walls of the fungicide-treated hyphae due to the detrimental effects of the fungicide on structure and functions of the hyphal membranes.