Fritz Maendy, Jakobsen Iver, Lyngkjær Michael Foged, Thordal-Christensen Hans, Pons-Kühnemann Jörn
Biometry and Population Genetics, Justus-Liebig-Universität Gießen, IFZ, Heinrich-Buff-Ring 26-32, 35392, Gießen, Germany.
Biosystems Department, Risø National Laboratory, Roskilde, Denmark.
Mycorrhiza. 2006 Sep;16(6):413-419. doi: 10.1007/s00572-006-0051-z. Epub 2006 Apr 14.
Mycorrhiza frequently leads to the control of root pathogens, but appears to have the opposite effect on leaf pathogens. In this study, we studied mycorrhizal effects on the development of early blight in tomato (Solanum lycopersicum) caused by the necrotrophic fungus Alternaria solani. Alternaria-induced necrosis and chlorosis of all leaves were studied in mycorrhizal and non-mycorrhizal plants over time course and at different soil P levels. Mycorrhizal tomato plants had significantly less A. solani symptoms than non-mycorrhizal plants, but neither plant growth nor phosphate uptake was enhanced by mycorrhizas. An increased P supply had no effect on disease severity in non-mycorrhizal plants, but led to a higher disease severity in mycorrhizal plants. This was parallel to a P-supply-induced reduction in mycorrhiza formation. The protective effect of mycorrhizas towards development of A. solani has some parallels to induced systemic resistance, mediated by rhizobacteria: both biocontrol agents are root-associated organisms and both are effective against necrotrophic pathogens. The possible mechanisms involved are discussed.
菌根通常能控制根部病原体，但对叶部病原体似乎有相反的作用。在本研究中，我们研究了菌根对由坏死营养型真菌链格孢引起的番茄早疫病发展的影响。随着时间推移并在不同土壤磷水平下，研究了菌根和非菌根植物中链格孢诱导的所有叶片坏死和黄化情况。菌根番茄植株的链格孢症状明显少于非菌根植株，但菌根既未促进植株生长，也未提高磷吸收。增加磷供应对非菌根植物的病情严重程度没有影响，但导致菌根植物病情更严重。这与磷供应诱导的菌根形成减少情况平行。菌根对链格孢发展的保护作用与由根际细菌介导的诱导系统抗性有一些相似之处：两种生物防治剂都是与根相关的生物体，并且都对坏死营养型病原体有效。文中讨论了可能涉及的机制。
