Even after death the endophytic fungus of Schedonorus phoenix reduces the arbuscular mycorrhizas of other plants

被引:64
作者
Antunes, P. M. [1 ]
Miller, J. [2 ]
Carvalho, L. M. [1 ]
Klironomos, J. N. [1 ]
Newman, J. A. [2 ]
机构
[1] Univ Guelph, Dept Integrat Biol, Guelph, ON N1G 2W1, Canada
[2] Univ Guelph, Dept Environm Biol, Guelph, ON N1G 2W1, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
arbuscular mycorrhizal fungi; allelopathy; AMF; Schedonorus phoenix; Neotyphodium; endophyte; spore germination;
D O I
10.1111/j.1365-2435.2008.01432.x
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
1. Plants can host microbial communities whose integrated functions are often responsible for their success. Understanding mechanisms regulating such functions is thus a major goal in ecology. 2. Fungal endophytes of grasses, particularly of the genus Neotyphodium, have been reported to reduce colonization of their host plant by arbuscular mycorrhizal (AM) fungi. However, it is unclear which mechanism(s) may explain the effects produced by the endophyte and whether these effects are present in nature. 3. We used Schedonorus phoenix (syn. Lolium arundinaceum) plants that were endophyte-free or infected with one of two strains of Neotyphodium coenophialum known to produce different putative allelochemicals to test the hypotheses that (i) allelopathic effects of the endophyte reduce AM fungal spore germination; and (ii) the allelochemical compound(s) are leached into the soil even after the death of S. phoenix, where they reduce AM fungal colonization of other plants. 4. In a first experiment, aqueous extracts from the shoots of S. phoenix were applied onto spores of the AM fungus Glomus intraradices to test germination effects. Both endophyte strains reduced spore germination by approximately 10% relative to endophyte-free controls. 5. In a second experiment, we placed dried shoot material ('thatch') on the soil surface of pots containing Bromus inermis, which were either inoculated with G. intraradices or not. We watered the plants through the thatch, relying upon leaching to translocate potential allelochemicals to the soil. AM fungal colonization of B. inermis was significantly reduced when thatch was infected with the common strain, but not with AR542, compared to the endophyte-free thatch. Furthermore, the arbuscule : vesicle ratio was 11-fold smaller when thatch was infected with the common strain compared to endophyte-free thatch, suggesting that G. intraradices was stressed by the presence of common strain-leachate. 6. We observed situations whereby two ecologically widespread plant-microbe symbioses interact. Potential mechanisms may include allelopathic effects, although other factors are also possible, and leaching is a mode of entry of putative endophyte-induced AM fungal inhibitors in soil. Understanding these processes is important as they affect AM fungal communities which contribute to plant success and, consequentially, grassland ecosystem dynamics.
引用
收藏
页码:912 / 918
页数:7
相关论文
共 51 条
[11]  
Douds DD, 2000, CURRENT ADVANCES IN MYCORRHIZAE RESEARCH, P11
[13]   Are endophytic fungi defensive plant mutualists? [J].
Faeth, SH .
OIKOS, 2002, 98 (01) :25-36
[14]  
Faeth Stanley H., 2002, P89, DOI 10.1017/CBO9780511542190.005
[15]   Does an asexual endophyte symbiont alter life stage and long-term survival in a perennial host grass? [J].
Faeth, Stanley H. ;
Hamilton, Cyd E. .
MICROBIAL ECOLOGY, 2006, 52 (04) :748-755
[16]   Molecular phylogeny of Acremonium and its taxonomic implications [J].
Glenn, AE ;
Bacon, CW ;
Price, R ;
Hanlin, RT .
MYCOLOGIA, 1996, 88 (03) :369-383
[17]   ROLE OF ACREMONIUM ENDOPHYTE OF FESCUE ON INHIBITION OF COLONIZATION AND REPRODUCTION OF MYCORRHIZAL FUNGI [J].
GUO, BZ ;
HENDRIX, JW ;
AN, ZQ ;
FERRISS, RS .
MYCOLOGIA, 1992, 84 (06) :882-885
[18]   INFLUENCE OF A CHANGE FROM TALL FESCUE TO PEARL-MILLET OR CRABGRASS ON THE MYCORRHIZAL FUNGAL COMMUNITY [J].
GUO, BZ ;
AN, ZQ ;
HENDRIX, JW ;
DOUGHERTY, CT .
SOIL SCIENCE, 1993, 155 (06) :398-405
[19]   A CLEARING TECHNIQUE FOR DETECTING THE FUNGAL ENDOPHYTE ACREMONIUM SP IN GRASSES [J].
HIGNIGHT, KW ;
MUILENBURG, GA ;
VANWIJK, AJP .
BIOTECHNIC & HISTOCHEMISTRY, 1993, 68 (02) :87-90
[20]   Reduced herbivore resistance from a novel grass-endophyte association [J].
Hunt, MG ;
Newman, JA .
JOURNAL OF APPLIED ECOLOGY, 2005, 42 (04) :762-769