The fungal endophyte Epichloë festucae var. lolii plays a limited role in mediating crown rust severity in perennial ryegrass

Abstract

Perennial ryegrass (Lolium perenne L.) is an important turf and forage species that often becomes infected with Puccinia coronata f. sp. lolii, the causal pathogen of crown rust. Disease control through clavicipitaceous endophytes has been proposed as a potential biocontrol. Two field experiments were designed to determine the influence of native Epichloë endophyte infection on natural rust development across a diverse panel of perennial ryegrass germplasm. Experiment 1 used an isogenic population design in which infected (E+) or endophyte-free (E−) clonal plants were nested within 14 perennial ryegrass entries. Experiment 2 consisted of isofrequent E+ and E− progeny from isogenic parents. Results showed the endophyte had no consistent main effect on crown rust severity among or within entries; however, several isogenic host pairs did show either favorable or antagonistic effects. Despite these sporadic effects, no differences were found between isofrequent family pairs, indicating the presence of a host × endophyte interaction. Genotypic and phenotypic data revealed that endophyte isolates were similar within entry, indicating that host genotype could be responsible for the highly specific endophyte effect on crown rust. The preponderance of host resistance in mediating rust severity was supported by large broad (>.75) and narrow-sense (.76) heritability estimates. These findings support the conclusion that endophyte infection does not play a substantial role in mediating crown rust severity on a population scale in perennial ryegrass.

Nitrogen fertilizer and clover inclusion effects on the establishment of fine fescue taxa

“…At each site, digital images (size 4,000 × 3,000 pixels) were collected with a lighted camera box, described by Heineck et al. (2020), every 7 or 14 d until 70 to 90 d after planting (DAP), and after winter on 1 May (∼8 mo after planting [MAP]), and 1 June (∼9 MAP) and analyzed with ImageJ (hue: 47–150; saturation: 0–255; brightness: 10–255) (v.1.52a; Schneider et al., 2012) to assess green vegetation cover (0‐100%). Using the methods of Braun et al.…”

Reciprocal Effects of Silicon Supply and Endophytes on Silicon Accumulation and Epichloë Colonization in Grasses

“…Epichloë-grass associations are known to benefit grasses in a number of ways, including increased growth (Gundel et al, 2013), better tolerance to water deficits (Rho et al, 2018) and resistance to pathogens (Xia et al, 2018) and herbivores (Bastias et al, 2017), the latter mainly via production of endophyte specific protective alkaloids (nitrogenous compounds) (Bastias et al, 2017). While some studies suggest endophytes play a limited role in stress alleviation (Niones and Takemoto, 2014;Wiewióra et al, 2015;Heineck et al, 2020), and might have antagonistic responses under extreme resource limitations conditions (Cheplick et al, 1989;Cheplick, 2007;Saikkonen et al, 2016), it is recognized that their beneficial effects are now widely reported (Kuldau and Bacon, 2008;Perez et al, 2017). Because of these benefits, animal-safe endophytes strains (e.g., AR1, AR31, AR584), that don't have the genes accountable for producing mammalian toxic alkaloids, are commercially available in marketed varieties of several perennial forage grasses such as tall fescue, perennial ryegrass, and cocksfoot (Gundel et al, 2013;Kauppinen et al, 2016).…”

A First Draft of the Core Fungal Microbiome of Schedonorus arundinaceus with and without Its Fungal Mutualist Epichloë coenophiala

“…Many of the most common genera are known plant pathogens ( Limonomyces , Parastagonospora ), and some pathogens known to be associated with tall fescue and related grasses were also found in our dataset, e.g., Puccinia spp. (rust) [ 52 , 53 ] and Fusarium oxysporum [ 54 ]. Based on the FungalTraits database [ 50 ], other common fungal guilds in our dataset include animal pathogens, endophytes, wood saprotrophs, and lichen parasites.…”