ROLE OF MELANIN IN APPRESSORIUM FUNCTION
ROLE OF MELANIN IN APPRESSORIUM FUNCTION
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DOI：
10.1016/0147-5975(89)90036-4
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发表时间：
1989-12-01
期刊：
影响因子：
--
通讯作者：
FERRARI, MA
中科院分区：
文献类型：
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作者：
HOWARD, RJ;FERRARI, MA
某些致病真菌的附着胞由于黑色素的离散细胞壁层而呈现深色。我们已经研究了附着胞黑色素的功能，使用野生型和黑色素缺乏菌株的稻瘟病菌和黑色素生物合成抑制剂三环唑。所有附着胞表现出一个单一的，圆形的，无壁孔对底层。在黑化和unmelanized附着胞的孔外接的材料环，孔环，这可能起到密封孔-基质界面。实验证据表明，附着胞紧密地粘附在表面上，黑色素在这种粘附中没有发挥主要作用。黑色素较少的附着胞一致和均匀的plasterized低溶质浓度，而黑化附着胞，如果形成在固体表面上，plasterized只有高得多的溶质浓度。此外，活的或热杀死的附着胞的细胞壁在质壁分离过程中由于细胞质破裂而变黑，但从未解除变黑，附着胞塌陷。黑色素对水和溶质具有不同的渗透性，允许密封的附着胞建立并维持高的内部溶质浓度，从而产生高的内部静水压力。我们认为，正是这种压力使病原体能够穿透塑料盖玻片的表面以及宿主。
Appressoria of certain pathogenic fungi appear darkly pigmented due to a discrete cell wall layer of melanin. We have studied the function of appressorial melanin using wild-type and melanin-deficient strains of the rice blast pathogen Magnaporthe grisea and the melanin biosynthesis inhibitor tricyclazole. All appressoria exhibited a single, circular, wall-less pore against the substratum. Pores in both melanized and unmelanized appressoria were circumscribed by a ring of material, the pore ring, which might function to seal the pore-substratum interface. Experimental evidence demonstrated that appressoria adhered tightly to surfaces and that melanin did not play a major role in that adhesion. Melanin-less appressoria were consistently and uniformly plasmolyzed by low solute concentrations, whereas melanized appressoria, if formed on a solid surface, were plasmolyzed only much higher solute concentrations. In addition, the cell wall of living or heat-killed melanized, but never unmelanized, appressoria collapsed during plasmolysis due to cytorrhysis. Melanin, having a differential permeability to water and solute, allowed sealed appressoria to establish and maintain a high internal solute concentration that created a high internal hydrostatic pressure. It is that pressure, we suggest, that empowers the pathogen to penetrate the surface of a plastic coverslip as well as the host.