亲密联盟：植物和他们的微共生体.ppt

In the traces to the left, Nod factor is introduced at the time of the vertical line. The change in fluorescence of a calcium reporter is shown over time in single root hairs of wild-type or each of three mutant Medicago truncatula lines. * Scale bar = 10 μm DNA content of S. meliloti bacteria and bacteroids isolated from nitrogen-fixing M. truncatula nodules was compared * Scale bar = 10 μm * * * TFs are transcription factors * * Orchids and Ericales plants associate with other fungi Many orchid seed will not germinate without their special fungal partner Cranberry (Vaccinium macrocarpon) and tea (Camellia sinensis) are both in the Ericale family and associate with ericoid mycorrhizal fungi Photo credits: Mark Brundrett; Cjboffoli; Melanurya The fungus gets sugars produced by photosynthesis The plant gets nitrogen and phosphorus from the soil The arbuscule provides a large surface area for nutrient exchange Plant cell Fungus Arbuscular mycorrhizal (AM) fungi penetrate into the plant cell The AM fungi-plant symbiosis is  400 million years old Remy, W., Taylor, T.N., Hass, H. and Kerp, H. (1994). Four hundred-million-year-old vesicular arbuscular mycorrhizae. Proc. Natl. Acad. Sci. USA 91: 11841-11843, copyright National Academy of Sciences, USA; Images courtesy of Griensteidl, Mark Brundrett 400 million year old fossilized AM fungus within plant cell This arbuscule was found inside a fossilized Devonian plant, Aglaophyton major Modern arbuscules within plant cells Arbuscular mycorrhizal fungi associate with ~80% of land plants Reprinted from Bonfante, P., and Genre, A. (2008). Plants and arbuscular mycorrhizal fungi: an evolutionary-developmental perspective. Trends Plant Sci. 13: 492-498 with permission from Elsevier. The plant – AM fungi symbiosis was an early innovation in land plant evolution The AM fungi symbiosis uses the common SYM pathway Myc factor Mycorrhization Receptor Nod factor Nodulation Receptor CCaMK SYMRK TFs NUPs CASTOR POLLUX CYCLOPS