Symbiosis with Neotyphodium uncinatum Endophyte May Increase the Competitive Ability of Meadow Fescue

Abstract

Infection with the endophyte Neotyphodium uncinatum (Gams, Petrini & Schmidt) Glenn, Bacon, Price & Hanlin may influence drought resistance and competitive ability of meadow fescue (Festuca pratensis Huds.). We determined endophyte‐related effects on some growth and physiological characteristics in one clone of meadow fescue. In a growth chamber experiment, meadow fescue and orchardgrass (Dactylis glomerata L.) were planted in pots as monocultures or binary mixtures, competing in the root systems. One group of plants was adequately watered to maintain the original pot weight (control). The other group was subjected to a gradually imposed water stress, defined as soil water deficit, during 25 d (stressed plants). After rewatering, plants were allowed to regrow for 3 wk. Endophyte infection increased shoot and root dry weight by 33 and 70%, respectively, in control meadow fescue plants, and by 24 and 69% in stressed plants. Infected (E +) plants had significantly greater competitive ability than noninfected (E−) plants when grown in E−/E+ binary mixture. In binary mixtures with orchardgrass, the competitive abilities of E− and E+ plants were reduced relative to that of E− and E+ plants grown as monocultures. In response to water stress, stomatal conductance was lower in E+ than in E− plants, regardless of root competition. Noninfected plants could not completely recover in leaf water potential when exposed to root competition with infected plants or orchardgrass. The greater competitive ability of E+ plants was related to improved root and shoot growth and enhanced drought resistance. Infection with N. uncinatum could confer a competitive advantage to the meadow fescue clone.

Effect of differentNeotyphodiumendophytes on root distribution of a perennial ryegrass(Lolium perenneL.) cultivar

“…did not change root/shoot ratios. In other work with meadow fescue, Malinowski et al (1997b) reported greater growth response in roots of endophyte-infected plants, than in the shoots, but did not present root/ shoot ratios. Lewis et al (1996) working with clonal ryegrass in solution culture found that endophyte infection decreased root/shoot ratios in both high and low N supply treatments, but the effect was transitory in the low N solution.…”

Multistrain infections of the grass Brachypodium sylvaticum by its fungal endophyte Epichloë sylvatica

“…This phenomenon is particularly well documented in the agricultural grasses Festuca arundinacea and Lolium perenne infected by Neotyphodium endophytes where these metabolites cause toxicosis in cattle and sheep (Rowan, 1993 ;Bacon, 1995). Infected plants also often show enhanced growth and increased competitive abilities (Clay et al, 1993 ;Malinowski et al, 1997), as well as increased resistance to drought, pests and\or pathogens (Kimmons et al, 1990 ;Gwinn & Gavin, 1992 ;West, 1994 ;Schuster et al, 1995 ;Elbersen & West, 1996).…”

Effects of cadmium stress on growth and anti-oxidative systems in Achnatherum inebrians symbiotic with Neotyphodium gansuense

“…Endophytes of Neotyphodium species and their sexual telemorphic genus Epichloë have been found in many cool-season grasses [4,5] and are associated with increased host resistance to abiotic and biotic stresses [6][7][8], nutrient acquisition [9] and competitive ability [10,11].…”