Endophytic fungi alter relationships between diversity and ecosystem properties

Rudgers, Jennifer A.; Koslow, Jennifer M.; Clay, Keith

doi:10.1046/j.1461-0248.2003.00543.x

Cited by 128 publications

(111 citation statements)

References 78 publications

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“…Such fungal consortia can have ecosystem-level effects. Endophytic colonization of one dominant grass can alter the abundance of other plant species (16), and AMF can alter the diversity and structure of a plant community (59,78,79). Rudgers and Clay (60) suggest that the differential competitive ability of plants colonized by endophytic fungi in comparison with plants that are not colonized may be important in defining plant community structure in stressful conditions.…”

Section: Discussionmentioning

confidence: 99%

Novel Root Fungal Consortium Associated with a Dominant Desert Grass

Porras-Alfaro

Herrera

Sinsabaugh

et al. 2008

Appl Environ Microbiol

197

149

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The broad distribution and high colonization rates of plant roots by a variety of endophytic fungi suggest that these symbionts have an important role in the function of ecosystems. Semiarid and arid lands cover more than one-third of the terrestrial ecosystems on Earth. However, a limited number of studies have been conducted to characterize root-associated fungal communities in semiarid grasslands. We conducted a study of the fungal community associated with the roots of a dominant grass, Bouteloua gracilis, at the Sevilleta National Wildlife Refuge in New Mexico. Internal transcribed spacer ribosomal DNA sequences from roots collected in May 2005, October 2005, and January 2006 were amplified using fungal-specific primers, and a total of 630 sequences were obtained, 69% of which were novel (less than 97% similarity with respect to sequences in the NCBI database). B. gracilis roots were colonized by at least 10 different orders, including endophytic, coprophilous, mycorrhizal, saprophytic, and plant pathogenic fungi. A total of 51 operational taxonomic units (OTUs) were found, and diversity estimators did not show saturation. Despite the high diversity found within B. gracilis roots, the root-associated fungal community is dominated by a novel group of dark septate fungi (DSF) within the order Pleosporales. Microscopic analysis confirmed that B. gracilis roots are highly colonized by DSF. Other common orders colonizing the roots included Sordariales, Xylariales, and Agaricales. By contributing to drought tolerance and nutrient acquisition, DSF may be integral to the function of arid ecosystems.Symbiotic associations of fungi and plants are ancient and phylogenetically diverse (4,9,11,42,43,60,64,69). Some of these fungi, notably mycorrhizal fungi, have received extensive study, but accumulating evidence indicates that many of the fungi associated with plant roots are dark septate fungi (DSF). These fungi are usually described as endophytes, whose functions have only recently been studied (43,44,76). DSF comprise a taxonomically diverse group (34, 37) characterized by melanized septate hyphae. Endophytes with hyaline hyphae are also common (e.g., see references 48, 53, and 76), but are less well characterized, because they are more difficult to detect in microscopic analysis and are sometimes considered contaminants in mycorrhizal fungal studies. Growing evidence showing the broad distribution and high root colonization rates of DSF in different ecosystems suggests that their functional importance may rival that of arbuscular mycorrhizal fungi (AMF) (1, 43), particularly for plants growing in stressed environments, such as alpine habitats and arid grasslands (8, 45a, 54, 56, 75). In these habitats, endophytic DSF and other rootassociated fungi allow some plants to increase their resistance to drought and heat and facilitate the acquisition of nutrients (23, 43, 45a, 50, 57, 76, 81).Desert environments are one of the most challenging ecosystems for plants and microorganisms (18,51,87). Biological activity, dive...

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Section: Discussionmentioning

confidence: 99%

Novel Root Fungal Consortium Associated with a Dominant Desert Grass

Porras-Alfaro

Herrera

Sinsabaugh

et al. 2008

Appl Environ Microbiol

197

149

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“…One condition that may reduce the effect of diversity on resistance to invasion is the presence of a mutualism that benefits the invader (Richardson et al 2000;Bruno et al 2003;Rudgers et al 2004). For example, the invasion of exotic Myrica may be facilitated by mutualistic interactions with nitrogen-fixing bacteria (Walker et al 1986) and by mutualisms with seed-dispersing birds (Woodward et al 1990).…”

Section: Introductionmentioning

confidence: 99%

“…However, systemic endophytes that are strictly vertically transmitted from the host plant to its seeds are commonly mutualistic (Clay and Schardl 2002). As these endophytes produce no externally visible symptoms, they are often overlooked in studies of plant diversity and invasion (see Rudgers et al 2004). Therefore, systemic, endophytic fungi, which are estimated to occur in 20-30% of all grass species (Leuchtmann 1992), represent a hidden factor that may help explain the varied results of prior studies on resistance to invasion and plant diversity.…”

Section: Introductionmentioning

confidence: 99%

Mutualistic fungus promotes plant invasion into diverse communities

2005

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Reducing the biological diversity of a community may decrease its resistance to invasion by exotic species. Manipulative experiments typically support this hypothesis but have focused mainly on one trophic level (i.e., primary producers). To date, we know little about how positive interactions among species may influence the relationship between diversity and invasibility, which suggests a need for research that addresses the question: under what conditions does diversity affect resistance to invasion? We used experimental manipulations of both plant diversity and the presence of an endophytic fungus to test whether a fungal mutualist of an invasive grass species (Lolium arundinaceum) switches the relationship between plant community diversity and resistance to invasion. Association with the fungal endophyte (Neotyphodium coenophialum) increased the ability of L. arundinaceum to invade communities with greater species diversity. In the absence of the endophyte, the initial diversity of the community significantly reduced the establishment of L. arundinaceum. However, establishment was independent of initial diversity in the presence of the endophyte. Fungal symbionts, like other key species, are often overlooked in studies of plant diversity, yet their presence may explain variation among studies in the effect of diversity on resistance to invasion.

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“…Esto vale en particular para los géneros Alternaria y Fusarium, pues, se conoce su distribución cosmopolita, su habilidad fitopatogénica en diversos hospedadores no especie-específicos (tanto en plantas silvestres como cultivadas), la producción de micotoxinas, su oportunismo en el hombre y su rol endofítico (Sridhar & Raviraja, 1995;Janardhanan & Ahmad, 1997;Kuldau & Yates, 2000;Rudgers et al, 2004;Rubini et al, 2005).…”

Section: Resultados Y Discusionunclassified