Physiological responses of Festuca arundinacea to fungal endophyte infection

Abstract

SUMMARYEnhanced growth rates of several grass species infected by fungal endophytes are known, hut the underlying changes in plant physiology are not. Carbon exchange rates (CER) and leaf conductances {g) of 13 genotypes of tall fescue {Festuca arundinacea Schreb. var. KY 31) infected by the fungal endophyte Acremonimn coenophialum Morgan-Jones and Gams were measured at ambient conditions. Endophyte-free ramets of the same genotypes were also measured. Correlations were calculated hetween environmental conditions at the time of measurement, and physiological responses. The only differential response of infected and uninfected ramets was to temperature. At low leaf temperatures no difference was seen between infected and uninfected plants. However, at leaf temperatures above 35 °C infected tall fescue plants photosynthesized at a significantly greater rate (20-25 %) than uninfected plants. This resulted from a decrease in the CER of uninfected plants, not an increase in the rate of infected plants, at high temperature. There were also significant infection x genotype interactions, indicating that the response to infection was specific to a given genotype. These results indicate that physiological responses of host plants to fungal endophyte infection depend both on the physical environment and the genotype of the plants.

Effects of Endophyte Infection in Tall Fescue (Festuca arundinacea: Poaceae) on Community Diversity

“…Our study indirectly shows that herbivory is less important in explaining this potential mutualism than previously thought and that endophyte-induced drought tolerance may be more crucial. This and other studies show a narrow ecological range where endophytes are markedly mutualistic (Cheplick et al 1989;West 1994;Marks and Clay 1996). For example, it is known that C 3 grasses are less successful than C 4 in more xeric conditions (Barnes et al 1983;Archer 1984).…”

“…Earlier and greater leaf rolling and better long-term survival under water stress are related to endophyte-infected versus uninfected F. arundinacea (Arachevaleta et al 1989). At high leaf temperatures, photosynthetic rates of up to 25% higher are found in infected plants (Marks and Clay 1996). Under water stress, infection-affected stomatal activity leads to reduced water loss from transpiration (Malinowski et al 1997) as well as maintained turgor pressure (Bacon and Hill 1996).…”

Metabolic Profiles ofLolium perenneAre Differentially Affected by Nitrogen Supply, Carbohydrate Content, and Fungal Endophyte Infection

“…Studies of photosynthetic processes in grasses infected with foliar endophytes are not conclusive and rates of net photosynthesis can be increased (Belesky et al, 1987;Amalric et al, 1999), unchanged or decreased (Spiering et al, 2006), depending on the growth phase of the host plants, nutrient status, and environmental conditions. Marks and Clay (1996) demonstrated an endophyte by temperature interaction, and Newman et al (2003) found an endophyte by N interaction on photosynthetic rates. Effects of endophyte infection on growth also strongly depend on host genotype, resource availability, and environmental stress (Belesky et al, 1989;Malinowski and Belesky, 2006;Morse et al, 2002;Cheplick and Cho, 2003;Hesse et al, 2003;Zabalgogeazcoa et al, 2006;Cheplick, 2007).…”

Phytochemical screening and antimicrobial activity of selected medicinal plant species

“…Phenol and its compound are distributed in many plants, phenolic compound are used for the treatment of many disorder and also due to its toxic action prevent the growth of many pathogens [14]. Flavonoids, sterol, and saponins are essential secondary chemical present in above 85 families, due to their multipurpose and specific chemistry they are used for the treatment of many disorder [15]. All these phytochemicals give a strong immunity in the form of resistance against many insects and herbivores as well [16].…”