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Most grasses host endophytic fungi, co-evolved organisms that can interact with their hosts from antagonism to mutualism. This study examined the impact of mating systems on host–endophyte interactions by utilizing endophyte-infected (E+) and endophyte-free (E−) populations of self-pollinating Lolium persicum and open-pollinating Lolium rigidum, collected from three regions of Iran. The evaluations in a pre-breeding process and two experiments were conducted on 1400 plants screened to select 126 half-sib (L. rigidum) and full-sib (L. persicum) families based on a limited space stress, morphological traits, and seed dormancy, respectively. It was found that endophytes generally have a significant and positive effect on reproductive traits and promoting effects in plants to strive for survival. Their impacts were population-dependent, and the E+ plants were superior when a population had higher biomass production and seed yield-related traits. Endophytes help to maintain the host’s genetic structure over generations, particularly in L. persicum. In this way, E+ populations exhibited the highest heritability and genetic advance for endophyte–host survival traits such as seed weight, number of seeds, plant height, and days to tillering in both species. In L. persicum, this also included acid-detergent fiber, neutral detergent fiber, crude protein, fat content, phosphorus content, number of tillers, and days to emergence. We demonstrated that artificial selection of morphological traits influenced plant–fungal fitness, such that selecting against seed dormancy significantly increased seed shattering but decreased fungal fitness.
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Anti-herbivory defences delivered by Epichloë fungal endophytes: a quantitative review of alkaloid concentration variation among hosts and plant parts
Abstract Background and AimsIn the subfamily Poöideae (Poaceae), certain grass species possess anti-herbivore alkaloids synthesized by fungal endophytes that belong to the genus Epichloë (Clavicipitaceae). The protective role of these symbiotic endophytes can vary, depending on alkaloid concentrations within specific plant–endophyte associations and plant parts. MethodsWe conducted a literature review to identify articles containing alkaloid concentration data for various plant parts in six important pasture species, Lolium arundinaceum, Lolium perenne, Lolium pratense, Lolium multiflorum|Lolium rigidum and Festuca rubra, associated with their common endophytes. We considered the alkaloids lolines (1-aminopyrrolizidines), peramine (pyrrolopyrazines), ergovaline (ergot alkaloids) and lolitrem B (indole-diterpenes). While all these alkaloids have shown bioactivity against insect herbivores, ergovaline and lolitrem B are harmful for mammals. Key ResultsLoline alkaloid levels were higher in the perennial grasses L. pratense and L. arundinaceum compared to the annual species L. multiflorum and L. rigidum, and higher in reproductive tissues than in vegetative structures. This is probably due to the greater biomass accumulation in perennial species that can result in higher endophyte mycelial biomass. Peramine concentrations were higher in L. perenne than in L. arundinaceum and not affected by plant part. This can be attributed to the high within-plant mobility of peramine. Ergovaline and lolitrem B, both hydrophobic compounds, were associated with plant parts where fungal mycelium is usually present, and their concentrations were higher in plant reproductive tissues. Only loline alkaloid data were sufficient for below-ground tissue analyses and concentrations were lower than in above-ground parts. ConclusionsOur study provides a comprehensive synthesis of fungal alkaloid variation across host grasses and plant parts, essential for understanding the endophyte-conferred defence extent. The patterns can be understood by considering endophyte growth within the plant and alkaloid mobility. Our study identifies research gaps, including the limited documentation of alkaloid presence in roots and the need to investigate the influence of different environmental conditions.
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- Award ID(s):
- 2030225
- PAR ID:
- 10559175
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Annals of Botany
- Volume:
- 133
- Issue:
- 4
- ISSN:
- 0305-7364
- Page Range / eLocation ID:
- 509 to 520
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/aob/mcae014
