Chemotropism in the arbuscular mycorrhizal fungus Glomus mosseae

• Published in: Mycorrhiza Vol. 15; no. 7; pp. 539 - 545
• Main Authors: Sbrana, C, Giovannetti, M
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-11-2005; Springer Nature B.V
• Subjects: Biological and medical sciences; chemotropism; Eruca sativa; Fundamental and applied biological sciences. Psychology; Fungi; Glomus mosseae; Host plants; host specificity; hyphae; Hyphae - growth & development; Medicago sativa; Mycorrhizae - growth & development; Mycorrhizae - physiology; mycorrhizal fungi; Ocimum basilicum; Parasitism and symbiosis; plant growth; Plant physiology and development; Plant Roots - metabolism; Roots; signal transduction; Symbiosis; Symbiosis - physiology; Tropism; Vaccinium myrtillus; vesicular arbuscular mycorrhizae; Symbiosis; Host recognition; Root; Growth; Arbuscular mycorrhizal fungi; Root-derived factors; Phycomycetes; Glomus mosseae; Fungi; Chemotropism; Life cycle; Growth reorientation; Mycorrhiza; Thallophyta
• ISSN: 0940-6360; 1432-1890
• DOI: 10.1007/s00572-005-0362-5

In this work, we report the occurrence of chemotropism in the arbuscular mycorrhizal (AM) fungus Glomus mosseae. Fungal hyphae were able to respond to host-derived signals by reorienting their growth towards roots and to perceive chemotropic signals at a distance of at least 910 microm from roots. In order to reach the source of chemotropic signals, hyphal tips crossed interposed membranes emerging within 1 mm from roots, eventually establishing mycorrhizal symbiosis. The specificity of chemotropic growth was evidenced by hyphal growth reorientation and membrane penetration occurring only in experimental systems set up with host plants. Since pre-symbiotic growth is a critical stage in the life cycle of obligate AM fungal symbionts, chemotropic guidance may represent an important mechanism functional to host root location, appressorium formation and symbiosis establishment.