Studying the controls on biomass allocation trade-offs in plants are important since they affect harvestable product yields and are critical to understanding symbiotic interactions.Epichloae fungal endophytes associat...Studying the controls on biomass allocation trade-offs in plants are important since they affect harvestable product yields and are critical to understanding symbiotic interactions.Epichloae fungal endophytes associate with cool-season grasses,growing systemically within the plant inter-cellular spaces and are transmitted through seeds.We explore the endophytes influence on the relationship between the plant reproductive and vegetative aboveground biomass(reproductive effort:RE)and on the trade-off between two components of the reproductive biomass,number and weight of panicles(RPN),using tall fescue as a model system.Naturally endophyte-colonized,manipulatively endophyte-free,and naturally endophyte-free plants from Northern European wild-populations together with the cultivar Kentucky-31 were grown under different environmental conditions(nutrients x water).The endophyte had an effect on the RPN(E+:6.19,ME-:4.68 and E-:4.40)which indicates how reproductive biomass is partitioned into number and mass of panicles,but not on RE(≈0.06).As expected,wild plants showed higher reproductive effort(≈0.06)compared to the cultivar KY-31(0.05),irrespective of endophyte presence.Endophyte-colonized plants had lighter panicles than endophyte-free plants,a pattern that was clear among low-yielding plants.Similarly,the tradeoff between RPN and RE was higher for endophytecolonized plants.This was again evident among plants with low RE indicating that colonized plants split the yield into either greater number of panicles and/or lighter panicles.The effect of vertically transmitted endophytes has earlier been studied as ratios(e.g.RE);however,our study shows that this approach may hide size-dependent endophyte effects on these relationships.Our study reveals that Neotyphodium endophyte affects trade-offs in tall fescue plants in a complex manner,and is influenced by a number of biological and abiotic factors.展开更多
Pooideae grasses may be colonized by systemic fungal endophytes.The fitness of endophyte depends entirely on resources and seed transmission from the host plant,while colonized plants may gain increased survival,growt...Pooideae grasses may be colonized by systemic fungal endophytes.The fitness of endophyte depends entirely on resources and seed transmission from the host plant,while colonized plants may gain increased survival,growth,and reproduction relative to their uncolonized conspecifics.Most research of endophyte-grass interactions have been carried out on few cultivars of tall fescue(Schedonorus phoenix)and their symbiont Neotyphodium coenophialum.Lack of studies using wild populations of tall fescue across the species natural distribution range,however,limits the understanding of the ecological and evolutionary role of the symbiosis in nature.We performed a common garden experiment in Southern Finland with three wild,tall fescue populations from northern Europe and the forage cultivar Kentucky-31(KY-31).For each population,we used naturally endophyte-colonized,naturally endophytecolonized but endophyte removed(decolonized),and naturally uncolonized plants to separate effects due to the host genotype from the endophyte.We evaluated growth variables and survival in four environmental treatments of varying water and nutrients.Supply of water and nutrients increased plant biomass and reproductive effort in all populations.This effect was higher for KY-31 plants which produced on average 55%more seeds than wild plants,indicating better adaptation to high resource environments.However,the higher incidence of Claviceps sp.and the low winter survival indicated KY-31 tall fescue is mal-adapted to Northern European conditions.Naturally colonized plants had greater plant biomass(≈12%),reproductive effort(≈22%)and seed mass(≈29%)than naturally uncolonized and decolonized plants.Nonetheless,endophyte colonization did not affect plant survival,and the effects of endophyte colonization on tiller number,panicle/tiller ratio and Claviceps sp.incidence depended on the population origin.In the wild populations,endophyte removal only reduced the number of tillers(≈29%lower),while the difference between naturally colonized and naturally uncolonized plants was not significant.Our results show that endophyte symbiont increases tall fescue performance in general,but the differences between wild populations and cultivars indicate adaptation to local habitats and agronomic management,respectively.The comparison of naturally endophyte-colonized and decolonized plants suggests certain plant genotype-endophyte combinations found within populations result from local selection pressures.展开更多
Epichloëfestucae is an endophytic fungus that infects systemically the aerial tissues of the host grass Festuca rubra.This fungus is transmitted vertically from the mother plant to seeds.Hypothetically,the presen...Epichloëfestucae is an endophytic fungus that infects systemically the aerial tissues of the host grass Festuca rubra.This fungus is transmitted vertically from the mother plant to seeds.Hypothetically,the presence of E.festucae could affect the infection of a plant by other fungal species.This could occur if E.festucae metabolites produced in planta interfere negatively with other fungal infections;or alternatively,if the modulation of plant defenses by the endophyte favour further fungal infections.We have analyzed the presence of culturable non-systemic endophytes in plants of F.rubra infected(E+)and not infected(E−)by E.festucae in two subarctic habitats,meadows and riverbanks in Northern Finland.The observed non-systemic endophyte infection frequencies were similar among E+and E−plants from riverbanks,and E+plants from meadows.In contrast to these,the infection frequency was significantly lower in E−plants from meadows.This result suggests that the presence of E.festucae is not a main factor determining the presence of non-systemic endophytes in plants.Instead,plant genetic characteristics related to compatibility with E.festucae and other endophytes in the more stable meadow populations might play a role in these fungus–fungus–plant interactions.As a result of the survey,18 different taxa of non-systemic endophytes were identified in plants of F.rubra.All were ascomycetes except for one basidiomycete.Three endophytic taxa could not be ascribed to a genus,but sequence data indicated that they were conspecific with other unidentified endophytes that have been isolated in cold biomes at different locations.展开更多
文摘Studying the controls on biomass allocation trade-offs in plants are important since they affect harvestable product yields and are critical to understanding symbiotic interactions.Epichloae fungal endophytes associate with cool-season grasses,growing systemically within the plant inter-cellular spaces and are transmitted through seeds.We explore the endophytes influence on the relationship between the plant reproductive and vegetative aboveground biomass(reproductive effort:RE)and on the trade-off between two components of the reproductive biomass,number and weight of panicles(RPN),using tall fescue as a model system.Naturally endophyte-colonized,manipulatively endophyte-free,and naturally endophyte-free plants from Northern European wild-populations together with the cultivar Kentucky-31 were grown under different environmental conditions(nutrients x water).The endophyte had an effect on the RPN(E+:6.19,ME-:4.68 and E-:4.40)which indicates how reproductive biomass is partitioned into number and mass of panicles,but not on RE(≈0.06).As expected,wild plants showed higher reproductive effort(≈0.06)compared to the cultivar KY-31(0.05),irrespective of endophyte presence.Endophyte-colonized plants had lighter panicles than endophyte-free plants,a pattern that was clear among low-yielding plants.Similarly,the tradeoff between RPN and RE was higher for endophytecolonized plants.This was again evident among plants with low RE indicating that colonized plants split the yield into either greater number of panicles and/or lighter panicles.The effect of vertically transmitted endophytes has earlier been studied as ratios(e.g.RE);however,our study shows that this approach may hide size-dependent endophyte effects on these relationships.Our study reveals that Neotyphodium endophyte affects trade-offs in tall fescue plants in a complex manner,and is influenced by a number of biological and abiotic factors.
基金supported by Finnish Academy grants 213401 and 209210Turku University Foundation.
文摘Pooideae grasses may be colonized by systemic fungal endophytes.The fitness of endophyte depends entirely on resources and seed transmission from the host plant,while colonized plants may gain increased survival,growth,and reproduction relative to their uncolonized conspecifics.Most research of endophyte-grass interactions have been carried out on few cultivars of tall fescue(Schedonorus phoenix)and their symbiont Neotyphodium coenophialum.Lack of studies using wild populations of tall fescue across the species natural distribution range,however,limits the understanding of the ecological and evolutionary role of the symbiosis in nature.We performed a common garden experiment in Southern Finland with three wild,tall fescue populations from northern Europe and the forage cultivar Kentucky-31(KY-31).For each population,we used naturally endophyte-colonized,naturally endophytecolonized but endophyte removed(decolonized),and naturally uncolonized plants to separate effects due to the host genotype from the endophyte.We evaluated growth variables and survival in four environmental treatments of varying water and nutrients.Supply of water and nutrients increased plant biomass and reproductive effort in all populations.This effect was higher for KY-31 plants which produced on average 55%more seeds than wild plants,indicating better adaptation to high resource environments.However,the higher incidence of Claviceps sp.and the low winter survival indicated KY-31 tall fescue is mal-adapted to Northern European conditions.Naturally colonized plants had greater plant biomass(≈12%),reproductive effort(≈22%)and seed mass(≈29%)than naturally uncolonized and decolonized plants.Nonetheless,endophyte colonization did not affect plant survival,and the effects of endophyte colonization on tiller number,panicle/tiller ratio and Claviceps sp.incidence depended on the population origin.In the wild populations,endophyte removal only reduced the number of tillers(≈29%lower),while the difference between naturally colonized and naturally uncolonized plants was not significant.Our results show that endophyte symbiont increases tall fescue performance in general,but the differences between wild populations and cultivars indicate adaptation to local habitats and agronomic management,respectively.The comparison of naturally endophyte-colonized and decolonized plants suggests certain plant genotype-endophyte combinations found within populations result from local selection pressures.
基金funding from INTERACT(grant agreement No.262693)under the European Community’s Seventh Framework Programme,from Academy of Finland(Project No.137909)Spanish Government(Project AGL2011-22783).
文摘Epichloëfestucae is an endophytic fungus that infects systemically the aerial tissues of the host grass Festuca rubra.This fungus is transmitted vertically from the mother plant to seeds.Hypothetically,the presence of E.festucae could affect the infection of a plant by other fungal species.This could occur if E.festucae metabolites produced in planta interfere negatively with other fungal infections;or alternatively,if the modulation of plant defenses by the endophyte favour further fungal infections.We have analyzed the presence of culturable non-systemic endophytes in plants of F.rubra infected(E+)and not infected(E−)by E.festucae in two subarctic habitats,meadows and riverbanks in Northern Finland.The observed non-systemic endophyte infection frequencies were similar among E+and E−plants from riverbanks,and E+plants from meadows.In contrast to these,the infection frequency was significantly lower in E−plants from meadows.This result suggests that the presence of E.festucae is not a main factor determining the presence of non-systemic endophytes in plants.Instead,plant genetic characteristics related to compatibility with E.festucae and other endophytes in the more stable meadow populations might play a role in these fungus–fungus–plant interactions.As a result of the survey,18 different taxa of non-systemic endophytes were identified in plants of F.rubra.All were ascomycetes except for one basidiomycete.Three endophytic taxa could not be ascribed to a genus,but sequence data indicated that they were conspecific with other unidentified endophytes that have been isolated in cold biomes at different locations.
