IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Linking the grass-endophyte symbiosis to symbiotic nitrogen-fixing bacteria of legumes and ecosystem processes
Autor/es:
GARCIA PARISI, PABLO ADRIÁN; GRIMOLDI, AGUSTÍN ALBERTO; LATTANZI, FERNANDO; OMACINI, MARINA
Lugar:
Cracovia
Reunión:
Congreso; 7th International Symbiosis Society Congress; 2012
Institución organizadora:
International Symbiosis Society
Resumen:
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There is currently much
interest in understanding how symbiosis affects ecosystems
functioning, but few studies have evaluated how ecosystem processes
change in response to multiple symbioses. Asexual endophytic fungi
(Neotyphodium
spp, Clavicipitaceae)
often inhabit healthy aerial tissues
of cool-seasongrasses,
conferring benefits such as biotic
and abiotic stress tolerance, growth enhancement, and increased
reproductive success. Ouraims were(1)toidentifythe
impact of
the grass-endophyte symbiosis ontherelationshipbetweena
neighbouring legumeanditsnitrogen-fixingsymbiont,and(2)to
assess the
effect ofbothsymbioseson
the aboveground net primary productivity(NPP).Weperformedan
outdoors experimentinN-limitedmicrocosmswhere4plantsof
the legumeTrifoliumrepens(Tr)
grewsurroundedby16plantsof
the annual grass Loliummultiflorum
(Lm).
Tr seedswere
either inoculatedwithRhizobiumleguminosarumornot,whileLmplantspresentedhighorlowproportionofendophyte-symbioticindividuals(Lm+orLm-respectively).
Lm+ plants
reduced the number of nodules in Tr
plants
(LRT, χ22=6.38,
p=0.04), but did not affect the amount of nitrogen fixed (Anova,
Endophyte: F1,20=0.22,
p=0.64). However, the apparenttransferoffixednitrogenfrom
the legumetothegrasswas slightly
higher in Lm+ than Lm- plants (F1,20=28.77,
p<0.01). The presence of each symbiontincreased
host plant NPP irrespectiveofitsneighbours
symbioticstatus(Rhizobiumfor
Tr:F1,20=16.6,p<0.01,EndophyteforLm:F1,19=15,3,p<0.01).
Microcosm NPP also increasedwhen
both symbiontswere
present (Rhizobium:F1,20=10.76,p<0.01;Endophyte:F1,20=5.54,p=0.02).
However, nor was this effect cumulative (RhizobiumxEndophyteinteraction:F1,20=0.01,p=0.92),nor
did symbioticplants
affect the
NPP of the neighbouringplants.
Instead,LmplantswerebenefitedfromsymbioticTrplantsbecauseof
nitrogen transfer.Theseresultssuggest,forthefirsttime,apossible
synergistic impactofbothsymbiosesinthefunctionofthewholecommunity.