[Objective] The objective of this study is to discuss the effect of intracellular DHN melanin ofSetosphaeria turcica on the appressorium turgor pressure generated and elucidate the invasive mechanism of S. turcica. [Method] In this research, the best conditions for appressorium formation of S. turcica were determined by inducing appressorium production. The appressorium cell wall pore sizes and turgor pressures of wild-type isolate 01-23 and melanin-deficient strains ΔSt3hnr of S. turcica were measured by a solute exclusion technique and incipient-cytorrhysis technique. [Result] The appressorium pore size of wild-type isolate 01-23 was 2.1-2.7 nm and it had a 5.4 MPa turgor pressure, while it was shown a range of 2.7-3.3 nm in melanin-deficient strainsΔSt3hnr and a lower pressure about 4.1 MPa. The results indicated that appressorium without melanin could not form a high turgor pressure resulting in losing the ability for penetrating. [ Conclusion] It is suggested that the melanin layer is significant in accumulation of excess turgor pressure and the turgor pressure of S. turcica play a major role in substance penetration.%[目的]探讨玉米大斑病菌胞内DHN黑色素在附着胞膨压产生过程中的作用,明确玉米大斑病菌的侵入机理.[方法]通过诱导玉米大斑病菌附着胞产生,确定附着胞形成的最佳条件,利用溶质排斥技术及incipient-cytorrhysis.技术对玉米大斑病菌野生型菌株01-23和黑色素缺失突变体△St3hnr附着胞细胞壁孔径大小和膨压进行测定.[结果]野生型菌株01-23细胞壁孔径范围是2.1-2.7nm,膨压在5.4MPa左右;黑色素缺失突变体△St3hnr细胞壁孔径范围是2.7-3.3nm,膨压在4.1MPa左右;缺乏黑色素的附着胞不能形成高膨压,丧失了穿透能力.[结论]黑色素层对溶质分子外渗的阻挡作用导致了附着胞高膨压的产生,膨压产生的机械穿透力在玉米大斑病菌穿透基质平面的过程中发挥了重要作用.
展开▼
