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1、The University of ChicagoThe University of ChicagoEcology and Evolution of Multigenomic Arbuscular Mycorrhizal Fungi. Author(s): Ian R. Sanders Source: The American Naturalist, Vol. 160, No. S4, CONSEQUENCES OF INFECTION FOR ECOLOGY AND EVOLUTION OF HOSTS A Symposium Organized by Nancy A. Moran (Oct
2、ober 2002), pp. S128-S141 Published by: The University of Chicago Press for The American Society of Naturalists Stable URL: http:/www.jstor.org/stable/10.1086/342085 . Accessed: 05/11/2014 07:35Your use of the JSTOR archive indicates your acceptance of the Terms Hodge et al.2001). The physiological
3、benefits conferred to the host* E-mail: Ian.Sandersie-bsg.unil.chAm. Nat. 2002. Vol. 160, pp. S128S141. ? 2002 by The University of Chicago. 0003-0147/2002/16004S-0008$15.00. All rights reserved.plant can result in strong effects on competition and co- existence among plants species.Consequently,thi
4、scanlead to effects on plant community structure (Grime et al. 1987), plant diversity, and phosphorus cycling (van der Heijden et al. 1998b; van der Heijden 2002). Some of theseeffects can also result in the alteration of fitness of organ- isms in other trophic levels, notably insect herbivores (Gan
5、ge and Brown 2002; Gehring and Whitham 2002). The mycorrhizal symbiosis is also of considerable rel- evance to understanding the evolution of mutualistic sym-bioses. The fossil record shows that the first land plants were colonized by arbuscular mycorrhizal fungi (Remy et al. 1995). It has been sugg
6、ested that earlylandplantswould have required the assistance of fungal symbionts for the acquisition of phosphorus in the substrates (primitive soils) that were colonized (Selosse and LeTacon 1998). Thus, the evolution of this ancient symbiosis may have been a major event that allowed the colonizati
7、on and evo-lution of terrestrial ecosystems based on carbon fixation by plants (Redecker et al. 2000). While this is highly spec- ulative, what is clear is that most plant lineages have coevolved with arbuscular mycorrhizal fungi for several hundred million years. Several plant groups, suchasCruci-
8、fereae, Brassicaceae, and many species of Cyperaceae,must have lost the symbiosis with arbuscular mycorrhizal fungi because the plants from which they have evolved are my- corrhizal. Many other plant families have also probably lost the symbiosis in favor of other mutualistic symbioses with other fu
9、ngi and microorganisms in order to obtain certain nutrients from the soil (e.g., ericoid mycorrhizal fungi, ectomycorrhizal fungi) or have evolved specialized structures or strategies for nutrient acquisition, such as cluster and proteoid roots that exude phosphatases with high activities (Skene 199
10、8). Despite the lack of AMF in some plant families, the majority of plant species remain mycorrhizal. In contrast to ectomycorrhizal symbioses, which appear to have been evolutionarily unstable and short lived (Hibbett et al. 2000), the arbuscular mycor- rhizal symbiosis has displayed remarkable sta
11、bility, even during periods of rapid plant radiation (Law 1985). It is not the intention here to review all the knownThis content downloaded from 195.194.14.6 on Wed, 5 Nov 2014 07:35:06 AM All use subject to JSTOR Terms and Conditions有些植物不再与 菌根共生。因为 这些植物的起源 物种仍与菌根共 生。Multigenomic Arbuscular Mycorrh
12、izal FungiS129ecological effects of mycorrhizal symbiosis. For an exten- sive review of that subject, readers should consult van der Heijden and Sanders (2002) and chapters therein. The main purpose here is to review key ecological studies on the symbiosis that indicate the importance of the AMF com
13、munity and population biology and to consider this in light of surprising recent discoveries on the general biological characteristics of AMF and their evolutionary genetics. The goal of this article is to illustrate why un- derstanding the population biology and evolutionary ge- netics of AMF is es
14、sential for understanding the ecological importance of this very common symbiosis, for its appli- cation in agriculture and environmental management,and for understanding how organisms evolve and coevolve over long periods of time in a mutualistic environment.Taxonomy and Biology of Arbuscular Mycor
15、rhizal FungiArbuscular mycorrhizal fungi (AMF) are zygomycetes inthe order Glomales. They are divided into five families Paraglomaceae, Archeosporaceae, Glomaceae, Acaulos- poraceae, and Gigasporaceae (Morton and Benny 1990; Morton and Redecker 2001). Considering that AMF have formed symbioses with
16、plants for the last 450460 million years (Simon et al. 1993; Remy et al. 1995; Redecker etal. 2000), there has been relatively little diversification and only about 162 species are recognized based on their mor- phological characteristics (see http:/invam.caf.wvu.edu/ index.html for an overview of AMF taxonomy). As Law (1985) pointed out, the radiation of their plant hosts dur- ing this time has been considerable. The life cycle and biological characteristics of the fungi need to be consi
