title: Effects of Hybrid and Non-hybrid Epichloë Endophytes and Their Associated Host Genotypes on the Response of a Native Grass to Varying Environments.
abstract: Asexual Epichloë endophytes are prevalent in cool season grasses, and many are of hybrid origin. Hybridization of asexual endophytes is thought to provide a rapid influx of genetic variation that may be adaptive to endophyte-host grass symbiota in stressful environments. For Arizona fescue (Festuca arizonica), hybrid symbiota are commonly found in resource-poor environments, whereas non-hybrid symbiota are more common in resource-rich environments. There have been very few experimental tests where infection, hybrid and non-hybrid status, and plant genotype have been controlled to tease apart their effects on host phenotype and fitness in different environments. We conducted a greenhouse experiment where hybrid (H) and non-hybrid (NH) endophytes were inoculated into plant genotypes that were originally uninfected (E-) or once infected with either the H or NH endophytes. Nine endophyte and plant genotypic group combinations were grown under low and high water and nutrient treatments. Inoculation with the resident H endophyte enhanced growth and altered allocation to roots and shoots, but these effects were greatest in resource-rich environments, contrary to expectations. We found no evidence of co-adaptation between endophyte species and their associated host genotypes. However, naturally E- plants performed better when inoculated with the hybrid endophyte, suggesting these plants were derived from H infected lineages. Our results show complex interactions between endophyte species of hybrid and non-hybrid origin with their host plant genotypes and environmental factors.
authors.affiliation: Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China. jiatong@sxu.edu.cn.
authors.forename: Tong
authors.initials: T
authors.lastname: Jia
authors.affiliation: Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC, 27412, USA.
authors.forename: Martina
authors.initials: M
authors.lastname: Oberhofer
authors.affiliation: Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC, 27412, USA.
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Shymanovich
authors.affiliation: Department of Biology, University of North Carolina Greensboro, 321 McIver Street, Greensboro, NC, 27412, USA.
authors.forename: Stanley H
authors.initials: SH
authors.lastname: Faeth
mesh_terms: D000222:Adaptation, Physiological; D018533:Biomass; D060026:Endophytes / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004783:Environmental Microbiology; D055329:Epichloe / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D031751:Festuca / Q000382:microbiology; D005838:Genotype; D006824:Hybridization, Genetic; D018517:Plant Roots / Q000382:microbiology; D006109:Poaceae / Q000382:microbiology*; D012621:Seasons; D013559:Symbiosis
keywords: Abiotic stress; Endophyte; Festuca arizonica; Hybridization; Inoculation; Plant genotype