Weinstein L H, Osmeloski J F, Wettlaufer S H, Galston A W
Boyce Thompson Institute, Ithaca, NY 14853, USA.
Plant Sci. 1987;51:311-6. doi: 10.1016/0168-9452(87)90208-1.
In higher plants, polyamines arise from arginine by one of two pathways: via ornithine and ornithine decarboxylase or via agmatine and arginine decarboxylase but in fungi, only the ornithine decarboxylase pathway is present. Since polyamines are required for normal growth of microorganisms and plants and since the ornithine pathway can be irreversibly blocked by alpha-difluoromethylornithine (DFMO) which has no effect on arginine decarboxylase, fungal infection of green plants might be controlled by the site-directed use of such a specific metabolic inhibitor. DFMO at relatively low concentrations provided effective control of the three biotrophic fungal pathogens studied, Puccinia recondita (leaf rust), P. graminis f. sp. tritici (stem rust), and Erysiphe graminis (powdery mildew) on wheat (Triticum aestivum L.) Effective control of infection by leaf or stem rust fungi was obtained with sprays of DFMO that ranged from about 0.01 to 0.20 mM in experiments where the inhibitor was applied after spore inoculation. The powdery mildew fungus was somewhat more tolerant of DFMO, but good control of the pathogen was obtained at less than 1.0 mM. In general, application of DFMO after spore inoculation was more effective than application before inoculation. Less control was obtained following treatment with alpha-difluoromethylarginine (DFMA) but the relatively high degree of control obtained raises the possibility of a DFMA to DFMO conversion by arginase.
在高等植物中，多胺通过两条途径之一由精氨酸产生：经由鸟氨酸和鸟氨酸脱羧酶，或经由胍丁胺和精氨酸脱羧酶；但在真菌中，仅存在鸟氨酸脱羧酶途径。由于多胺是微生物和植物正常生长所必需的，且由于鸟氨酸途径可被对精氨酸脱羧酶无作用的α-二氟甲基鸟氨酸（DFMO）不可逆地阻断，因此，通过定点使用这种特异性代谢抑制剂，有可能控制绿色植物的真菌感染。相对低浓度的DFMO有效地控制了所研究的三种活体营养型真菌病原体，即小麦上的隐匿柄锈菌（叶锈病）、小麦秆锈病菌（秆锈病）和禾本科布氏白粉菌（白粉病）。在孢子接种后施用抑制剂的实验中，用浓度范围约为0.01至0.20 mM的DFMO喷雾，可有效控制叶锈菌或秆锈菌的感染。白粉菌对DFMO的耐受性略强一些，但在浓度低于1.0 mM时也能很好地控制该病原体。一般来说，在孢子接种后施用DFMO比在接种前施用更有效。用α-二氟甲基精氨酸（DFMA）处理后获得的防治效果较差，但所获得的相对较高的防治程度增加了精氨酸酶将DFMA转化为DFMO的可能性。
