Evolution of Mutualistic Endophytes from Plant Pathogens

Schardl, C. L.; Clay, Keith

doi:10.1007/978-3-642-60647-2_14

Cited by 37 publications

(27 citation statements)

References 86 publications

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“…(4/99-1 type) is carried by seeds as a viable propagule and can be vertically transmitted to the next generation of the host. The same type of transmission is found in Neotyphodium endophytes (Schardl and Clay 1997). Third, we simulated a situation in which fungal propagules would be present in the soil.…”

Section: Discussionmentioning

confidence: 82%

“…We observed some variation with respect to year and site. The samples did not show fungal stroma formation as it had been reported for some Epichloë endophytes causing "choke disease" (Schardl and Clay 1997). We do not yet know if seeds that did not produce a signal carried one of the other fungi that we had initially isolated from seeds as well (discussed above).…”

Section: Detection Of a Stagonospora Sp In Field Samplesmentioning

confidence: 72%

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Endophytic Fungal Mutualists: Seed-Borne Stagonospora Spp. Enhance Reed Biomass Production in Axenic Microcosms

Ernst¹,

Mendgen²,

Wirsel³

2003

MPMI

114

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Fungal endophytes mainly belong to the phylum Ascomycota and colonize plants without producing symptoms. We report on the isolation of seed-borne fungal endophytes from Phragmites australis (common reed) that were ascribed to the genus Stagonospora. Nested polymerase chain reaction (PCR) assays revealed that a Stagonospora sp. regularly colonized reed as shown for a period of three years. In spring, it was only detected in roots, whereas in autumn, it could frequently be found in all organs, including seeds. Microcosm experiments revealed that seeds harbored viable propagules of the fungus that colonized the developing germling, indicating vertical transmission. Endophytic growth was confirmed by immunofluorescence microscopy, reisolation of the fungus after surface sterilization, and PCR. Aseptic microcosms were established for studying fungal contributions towards host vitality. Several Stagonospora isolates enhanced reed biomass. Seed-borne endophytic Stagonospora spp. thus can provide improved vigor to common reed, which could be most important when seed-derived germlings establish new reed stands.Additional keywords: ITS phylogeny, Phaeosphaeria.Fungi living in close association with plants can have effects on their host that range from detrimental to beneficial, depending on the partners involved and additional biotic and abiotic factors. Mycorrhiza is a well-documented type of a symbiotic interaction that is found at roots of the majority of higher plants. It is well known that mycorrhizal fungi are important for retrieving nutrients from soil and allocating them to their hosts (Hodge et al. 2001;Landeweert et al. 2001;Sharma et al. 1997). Endophytes represent another type of a putative symbiotic interaction between fungi and plants. Endophytes live within plant tissue without producing overt symptoms. Endophytic fungi have been recovered from all vegetative organs and from a broad range of plants growing from tropical to alpine habitats, indicating that these associations are widespread in nature (Carroll 1988;Petrini et al. 1992). Endophytes represent a wide taxonomical range of fungi, mostly within the phylum Ascomycota. Caroll (1988) distinguished two types of endophytic mutualism. Constitutive endophytic mutualism is typified by a systemic infection of grasses in genera Festuca, Lolium, and a few others in the family Poaceae with fungi of the anamorph genus Neotyphodium and the corresponding teleomorph genus Epichloë (family Clavicipitaceae, phylum Ascomycota) (Schardl 2001). These fungi proliferate in infected plants and are often vertically transmitted by seeds to the next generation of the host. It has been shown that these fungi improve the vitality of their hosts by increasing resistance against grazing, insects, drought, and microbial parasites (Clay 1992;Leuchtmann 1992;Schardl 2001). Furthermore, they improve biomass production and nutrient status (Arachevaleta et al. 1989;Groppe et al. 1999;Latch et al. 1985;Malinowski et al. 2000). On the other hand, Caroll (1988) characterized inducible en...

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Section: Discussionmentioning

confidence: 82%

Section: Detection Of a Stagonospora Sp In Field Samplesmentioning

confidence: 72%

Endophytic Fungal Mutualists: Seed-Borne Stagonospora Spp. Enhance Reed Biomass Production in Axenic Microcosms

Ernst¹,

Mendgen²,

Wirsel³

2003

MPMI

114

View full text Add to dashboard Cite

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“…Endophytes were subsequently described as fungi and bacteria that spend the most or part of their life cycle internally and asymptomatically in the healthy living tissues of plants [9,10]. It is believed that fungal endophytes originated from pathogenic fungi which either lost their virulence or exhibit extended latent periods [11,12]. Fungal endophytes colonize either locally or systemically in inter- or intra-cellular locations [13].…”

Section: Introductionmentioning

confidence: 99%

Fungal Endophytes from Three Cultivars of Panax ginseng Meyer Cultivated in Korea

Park¹,

Lim²,

Park³

et al. 2012

Journal of Ginseng Research

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In order to investigate the diversity of endophytes, fungal endophytes in Panax ginseng Meyer cultivated in Korea were isolated and identified using internal transcribed spacer (ITS) sequences of ribosomal DNA. Three cultivars of 3-year-old ginseng roots (Chunpoong, Yunpoong, and Gumpoong) were used to isolate fungal endophytes. Surface sterilized ginseng roots were placed on potato dextrose agar plates supplemented with ampicilin and streptomycin to inhibit bacterial growth. Overall, 38 fungal endophytes were isolated from 12 ginseng roots. According to the sequence analysis of the ITS1-5.8S-ITS2, 38 fungal isolates were classified into 4 different fungal species, which were Phoma radicina, Fusarium oxysporum, Setophoma terrestris and Ascomycota sp. 2-RNK. The most dominant fungal endophyte was P. radicina in 3 cultivars. The percentage of dominant endophytes of P. radicina was 65.8%. The percentage of colonization frequency of P. radicina was 80%, 52.9%, and 75% in Chunpoong, Yunpoong, and Gumpoong, respectively. The second most dominant fungal endophyte was F. oxysporum. The diversity of the fungal endophytes was low and no ginseng cultivar specificity among endophytes was detected in this study. The identified endophytes can be potential fungi for the production of bioactive compounds and control against ginseng pathogens.

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“…Ironically, though studies of toxic darnel and its endophyte were an important clue leading to the discovery that endophytic fungi cause such maladies, N. occultans has never been definitively implicated in livestock toxicosis. Meanwhile, numerous studies have established that N. coenophialum, N. lolii, and related endophytes are mutualists that provide a wide range of important benefits to their host plants (reviewed in Clay, 1990;Schardl and Clay, 1997). For this reason, the simple solution of removing endophyte to address livestock toxicosis has been impractical in large parts of the world.…”

Section: Taxonomy and Historymentioning

confidence: 98%

“…Fungal symbionts of the related genera Epichloë (which have a sexual state) and Neotyphodium (strictly asexual) are symbionts of many cool-season grasses (subfamily Pooideae) (Clay and Leuchtmann, 1989;, to which they provide a variety of fitness enhancements such as increased resistance to herbivory, parasitism, and drought, as well as growth enhancements (reviewed in Clay, 1990;Schardl and Clay, 1997) and improved nutrient acquisition (Malinowski and Belesky, 1999). Interest in these fungal "endophytes" at the turn of the 20th century was sparked by observations of toxicoses to animals grazing certain grasses.…”

Section: Taxonomy and Historymentioning

confidence: 99%