Effects of biotic and abiotic stress on the growth of three genotypes of <i>Lolium perenne</i> with and without infection by the fungal endophyte <i>Neotyphodium lolii</i>

Lewis, G. C.

doi:10.1111/j.1744-7348.2004.tb00316.x

Cited by 69 publications

(32 citation statements)

References 25 publications

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“…Resource limitation can increase the cost of supporting some endophytes (Cheplick 2004;Müller and Krauss 2005), potentially leading to the interaction shift from mutualism to parasitism or commensalism (Marks and Clay 2007). In fact, many of the studies that have found improved growth in EI grasses were done under benign conditions of moderate to high soil nutrient availability (Cheplick et al 1989;Ravel et al 1999;Hesse et al 2003;Lewis 2004;Ren et al 2009). If enhanced drought resistance, combined with nitrogen (N) enrichment, is a common result of endophyte symbiosis, then increases in the severity and duration of drought could drive the replacement of EF grasses by EI hosts.…”

Section: Introductionmentioning

confidence: 96%

Benefits of a symbiotic association with endophytic fungi are subject to water and nutrient availability in Achnatherum sibiricum

et al. 2011

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Symbiotic relationships with microbes may influence how plants respond to environmental change. Here, we investigated how fungal endophyte infection affected the growth of a native grass under altered water and nutrient availability. In a two-month field experiment, we compared the performance of endophyte-infected (EI) and endophyte-free (EF) Achnatherum sibiricum subjected to four treatments comprised of a factorial combination of two levels of water availability and two levels of fertilization. The greatest benefits of endophyte infection occurred in the well-watered fertilized treatment. With reduced water and/or nutrient availability, the benefits declined. EI plants subjected to drought and fertilization had higher root:shoot ratios and allocated more nitrogen to photosynthetic machinery and thus had a higher net photosynthetic rate than EF counterparts. In the wellwatered unfertilized treatment, EF plants allocated more nutrients to photosynthetic machinery, while EI plants allocated more resources to defense. Thus EI plants were superior to EF plants in terms of nutrient conservation. In the drought unfertilized treatment, no significant difference occurred between EI and EF plants. Our results support the idea that the endophytegrass interactions are dependent on available resources. However, we did not find a clear cost of endophyte infection. For A. sibiricum, fertilizer addition resulted in greater benefits of the symbiosis for plant growth, but this advantage decreased under drought.

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Section: Introductionmentioning

confidence: 96%

Benefits of a symbiotic association with endophytic fungi are subject to water and nutrient availability in Achnatherum sibiricum

et al. 2011

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“…First, relatively high infection frequencies have been observed in natural grass populations exhibiting little or no evidence that the fungus confers a reproductive advantage to its host (Saikkonen et al 1998;Faeth & Hamilton 2006). In fact, experimental evidence of a positive effect of endophytes on the fitness of their hosts has not been consistent (Cheplick et al 1989;Saikkonen et al 1998;Faeth 2002;Faeth & Sullivan 2003;Cheplick 2004;Lewis 2004;Faeth & Hamilton 2006); and modelling has demonstrated that local persistence of endophyte infection should be possible in the absence of such mutualistic effects, as a result of metapopulation dynamics (Saikkonen et al 2002). Second, natural populations often exhibit intermediate infection levels in contrast to modelling results showing that the frequency of infected plants in a population should equilibrate at 100% if the only driver was host fitness enhancement (Clay 1993;Ravel et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Neotyphodiumendophyte infection frequency in annual grass populations: relative importance of mutualism and transmission efficiency

et al. 2008

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Persistence and ubiquity of vertically transmitted Neotyphodium endophytes in grass populations is puzzling because infected plants do not consistently exhibit increased fitness. Using an annual grass population model, we show that the problems for matching endophyte infection and mutualism are likely to arise from difficulties in detecting small mutualistic effects, variability in endophyte transmission efficiency and an apparent prevalence of non-equilibrium in the dynamics of infection. Although endophytes would ultimately persist only if the infection confers some fitness increase to the host plants, such an increase can be very small, as long as the transmission efficiency is sufficiently high. In addition, imperfect transmission limits effectively the equilibrium infection level if the infected plants exhibit small or large reproductive advantage. Under frequent natural conditions, the equilibrium infection level is very sensitive to small changes in transmission efficiency and host reproductive advantage, while convergence to such an equilibrium is slow. As a consequence, seed immigration and environmental fluctuation are likely to keep local infection levels away from equilibrium. Transient dynamics analysis suggests that, when driven by environmental fluctuation, infection frequency increases would often be larger than decreases. By contrast, when due to immigration, overrepresentation of infected individuals tends to vanish faster than equivalent overrepresentation of noninfected individuals.

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“…Subsequently, Belesky et al (1991) reported that the endophyte infection did not affect carbohydrate accumulation in tall fescue at low N supply; therefore, they thought that the endophyte infection was not detrimental to the host plant even under nutrient limited conditions. In perennial ryegrass, Lewis (2004) reported that EI grass used N more effectively than EF grass when grown at low N availability. Other studies with perennial ryegrass, however, showed minimal or inconsistent effects of endophyte at low N concentrations (Durand et al 2002).…”

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confidence: 99%

“…On one hand, the grasses provide photosynthates for the fungi; on the other hand, the endophytes can enhance the hosts' growth and protect them from biotic and abiotic stresses, contributing thus to their adaptability. Abiotic attributes affected by Neotyphodium endophytes include drought resistance (Hesse et al 2003), light stress (Lewis 2004), high temperature (Marks and Clay 1996), mineral stress, etc. Studies on endophyte-related responses of grasses to nutrient acquisition focused on the influence of nitrogen, since this element is a constituent of alkaloids in infected plants.…”

mentioning

confidence: 99%

Response of Neotyphodium lolii-infected perennial ryegrass to phosphorus deficiency

Ren¹,

Gao²,

Fang³

2007

Plant Soil Environ.

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It has been demonstrated that endophyte-infected (EI) ryegrass performed better in response to N deficiency than its endophyte-free (EF) counterpart. When P is considered, there is a lack of related information. In this study, Lolium perenne L. infected with Neotyphodium lolii was employed to establish EI and EF populations. Soil-grown EI and EF ryegrass were tested for their responses to P deficiency. The results showed that the endophyte infection improved the adaptability of ryegrass to P deficiency. When P was limited, EI roots were significantly longer (EI, 398.8; EF, 323.4 m/pot) and heavier (EI, 30.58; EF, 23.20 g/pot) than EF roots; the root: shoot ratio of EI plants was greater than that of EF plants (P < 0.05). The content of total phenolics and organic acids was significantly greater for EI roots than for EF roots at low P supply; the concentration of both, however, was not improved by the endophyte infection. This suggested that it was the higher root dry weight (DW) that contributed to the higher content of total phenolics and organic acids for EI plants, and the endophyte infection might have negligible effects on chemical modification of perennial ryegrass. Endophyte infection did not increase P uptake rate but did significantly improve P use efficiency of ryegrass in response to P deficiency (EI, 0.734; EF, 0.622 g DW/mg P).

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Effects of biotic and abiotic stress on the growth of three genotypes of Lolium perenne with and without infection by the fungal endophyte Neotyphodium lolii

Cited by 69 publications

References 25 publications

Benefits of a symbiotic association with endophytic fungi are subject to water and nutrient availability in Achnatherum sibiricum

Benefits of a symbiotic association with endophytic fungi are subject to water and nutrient availability in Achnatherum sibiricum

Neotyphodiumendophyte infection frequency in annual grass populations: relative importance of mutualism and transmission efficiency

Response of Neotyphodium lolii-infected perennial ryegrass to phosphorus deficiency

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