An increasing need for productive and stress resilient Festulolium amphiploids: What can be learnt from the stable genomic composition of Festuca pratensis subsp. apennina (De Not.) Hegi?

Kopecký, D., Harper, J., Bartoš, J., Gasior, D., Vrána, J., Hřibová, E., Boller, B., Ardenghi, N.M.G., Šimoníková, D., Doležel, J., Humphreys, M.W.
FRONTIERS IN ENVIRONMENTAL SCIENCE 4: 66, 2016

Keywords: amphiploidy, Festuca pratensis subsp. apennina (De Not.) Hegi, chromosome pairing, diploidization, Festulolium breeding
Abstract: GenomecompositionofFestucapratensissubsp.apennina(DeNot.)Hegi,atetraploidfescuespeciesnativetothetallforbscommunitiesofsouth-easternEuropeataltitudesbetween1100and2200ma.s.l.hasbeenthesubjectofsomedebatebygrasstaxonomists.OurcytogeneticanalysesincludingfluorescenceinsituhybridizationwithprobesforgenomicDNAandselectedDNArepeatsrevealedthespeciestobeallotetraploidandderivedfrominterspecifichybridizationbetweenF.pratensisHuds.,aspeciesconfinedtograsslandatloweraltitudes,andasofarunknownFestucaspecies.Besidestetraploids,triploids,andpentaploidswerefoundgrowinginAlpinemeadowsincloseassociationwithF.pratensissubsp.apennina.TriploidcytotypespredominatedatmanysitesinSwitzerlandandRomania,andinsomelocalities,theyweretheonlycytotypesobserved.CytogeneticanalysesrevealedthetriploidstobehybridsbetweendiploidF.pratensisandtetraploidF.pratensissubsp.apennina,whilethepentaploidcytotypesoriginatedfromhybridizationbetweenF.pratensissubsp.apenninaandhexaploidF.arundinaceaSchreb.,aclosely-relatedspeciesgrowinginaclosevicinitytoF.pratensissubsp.apennina.ParentalgenomesofF.pratensissubsp.apenninaandofthetriploidandpentaploidhybridsshowednoevidenceofhomoeologouschromosomepairingandinterspecificrecombination,supportingpreviousobservationofadisomicinheritanceatmeiosis,wherechromosomepairingwasrestrictedtobivalentassociations.Ahypothesisispresentedthatachromosomepairingregulator(s),reportedpreviouslyinotherpolyploidbroad-leavedfescuespeciesoftheFestucasubg.Schedonorus,ispresentandfunctionalinF.pratensissubsp.apennina.Itislikelythatacommonancestors’genomethatcarriesthechromosomepairingregulator(s)ispresentinallpolyploidbroad-leavedfescuespecies,anditsacquisitionwasakeyeventthatenabledspeciation,anddevelopmentofapolyploidserieswithin Kopecký et al. Acquiring Genome Stability in Fescues Festuca. Identification of a functional chromosome pairing regulator capable of stabilizing advantageous genome combinations in hybrids within the Lolium-Festuca complex would greatly assist in development of stable Festulolium cultivars. Its expression within Festulolium amphiploid cultivars would assist strategies aimed at climate-proofing productive European grasslands to combat exposures to stress conditions.
DOI: 10.3389/fenvs.2016.00066
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IEB authors: Jan Bartoš, Jaroslav Doležel, Eva Hřibová, David Kopecky, Jan Vrána