Epichloë Endophyte-Promoted Seed Pathogen Increases Host Grass Resistance Against Insect Herbivory

Abstract

Plants host taxonomically and functionally complex communities of microbes. However, ecological studies on plant–microbe interactions rarely address the role of multiple co-occurring plant-associated microbes. Here, we contend that plant-associated microbes interact with each other and can have joint consequences for higher trophic levels. In this study we recorded the occurrence of the plant seed pathogenic fungus Claviceps purpurea and aphids (Sitobion sp.) on an established field experiment with red fescue (Festuca rubra) plants symbiotic to a seed transmitted endophytic fungus Epichloë festucae (E+) or non-symbiotic (E–). Both fungi are known to produce animal-toxic alkaloids. The study was conducted in a semi-natural setting, where E+ and E– plants from different origins (Spain and Northern Finland) were planted in a randomized design in a fenced common garden at Kevo Subarctic Research Station in Northern Finland. The results reveal that 45% of E+ plants were infected with Claviceps compared to 31% of E– plants. Uninfected plants had 4.5 times more aphids than Claviceps infected plants. By contrast, aphid infestation was unaffected by Epichloë symbiosis. Claviceps alkaloid concentrations correlated with a decrease in aphid numbers, which indicates their insect deterring features. These results show that plant mutualistic fungi can increase the infection probability of a pathogenic fungus, which then becomes beneficial to the plant by controlling herbivorous insects. Our study highlights the complexity and context dependency of species–species and multi-trophic interactions, thus challenging the labeling of species as plant mutualists or pathogens.

Fungal Endophytes to Combat Biotic and Abiotic Stresses for Climate-Smart and Sustainable Agriculture

“…Epichloe sp. offers biotic resistance to its host plant and controls herbivorous insects ( Laihonen et al, 2022 ). Piriformospora indica , a root colonizing filamentous fungus belonging to the Basidiomycota class, reside in association with xerophytic plants specifically, found to have a broad host range including most angiosperms viz.…”

ERGOT Claviceps purpurea (Fries) Tulasne ALKALOID DIVERSITY AND VIRULENCE: EVOLUTION, GENETIC DIVERSIFICATION, AND METABOLIC ENGINEERING (review)

“…Стоит еще раз подчеркуть, что определение паразитарных грибов как растительных мутуалистов или патогенов остается весьма размытым, периодически публикуются новые данные, свидетельствующие в пользу как первого, так и второго утверждения (204). Экспериментально показано, что инфицирование спорыньей у овсяницы красной (Festuca rubra), образующей симбиоз с эндофитным грибом Epichloe festucae, в 4,5 раза снижает поражение растений тлей (Sitobion sp.)…”

“…Экспериментально показано, что инфицирование спорыньей у овсяницы красной (Festuca rubra), образующей симбиоз с эндофитным грибом Epichloe festucae, в 4,5 раза снижает поражение растений тлей (Sitobion sp.) (204,205). При этом растения, содержащие симбиотический эндофит, были более подвержены инфекции Claviceps (45 % растений E + против 31 % растений E  ) (204).…”

“…При этом растения, содержащие симбиотический эндофит, были более подвержены инфекции Claviceps (45 % растений E + против 31 % растений E  ) (204). В то же врем присутствие Epichloe occultans в Lolium multiflorum и Epichloe gansuensis в Achnatherum inebrians коррелировало со снижением частоты инфицирования C. purpurea, то есть, вероятно, у некоторых видов растений представители рода Epichloe опосредуют защиту от C. purpurea (204,(206)(207)(208). В этих случаях рост устойчивости к патогенам может быть результатом повышения иммунокомпетентности хозяина или прямой конкуренции между спорыньей и эндофитным штаммом Epichloe (204,209,210).…”

Increasing the activities of protective enzymes is an important strategy to improve resistance in cucumber to powdery mildew disease and melon aphid under different infection/infestation patterns

“…Several recent reports have systematically studied the relationships among pathogens, insects, and host plants ( Gross et al, 2021 ; van Dijk et al, 2021 ; Franco et al, 2022 ; Laihonen et al, 2022 ). Of these, research on insect-virus-host plant systems is the most extensive ( Ziebell et al, 2011 ; Casteel et al, 2015 ; Flasco et al, 2021 ; Wang Y. F. et al, 2021 ).…”