AUTHOR=Kopecký David , Harper John , Bartoš Jan , Gasior Dagmara , Vrána Jan , Hřibová Eva , Boller Beat , Ardenghi Nicola M. G. , Šimoníková Denisa , Doležel Jaroslav , Humphreys Mike W. 

TITLE=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?

JOURNAL=Frontiers in Environmental Science

VOLUME=4

YEAR=2016

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2016.00066

DOI=10.3389/fenvs.2016.00066

ISSN=2296-665X

ABSTRACT=<p>Genome composition of <italic>Festuca pratensis</italic> subsp. <italic>apennina</italic> (De Not.) Hegi, a tetraploid fescue species native to the tall forbs communities of south-eastern Europe at altitudes between 1100 and 2200 m a.s.l. has been the subject of some debate by grass taxonomists. Our cytogenetic analyses including fluorescence <italic>in situ</italic> hybridization with probes for genomic DNA and selected DNA repeats revealed the species to be allotetraploid and derived from interspecific hybridization between <italic>F. pratensis</italic> Huds., a species confined to grassland at lower altitudes, and a so far unknown <italic>Festuca</italic> species. Besides tetraploids, triploids, and pentaploids were found growing in Alpine meadows in close association with <italic>F. pratensis</italic> subsp. <italic>apennina</italic>. Triploid cytotypes predominated at many sites in Switzerland and Romania, and in some localities, they were the only cytotypes observed. Cytogenetic analyses revealed the triploids to be hybrids between diploid <italic>F. pratensis</italic> and tetraploid <italic>F. pratensis</italic> subsp. <italic>apennina</italic>, while the pentaploid cytotypes originated from hybridization between <italic>F. pratensis</italic> subsp. <italic>apennina</italic> and hexaploid <italic>F. arundinacea</italic> Schreb., a closely-related species growing in a close vicinity to <italic>F. pratensis</italic> subsp. <italic>apennina</italic>. Parental genomes of <italic>F. pratensis</italic> subsp. <italic>apennina</italic> and of the triploid and pentaploid hybrids showed no evidence of homoeologous chromosome pairing and interspecific recombination, supporting previous observation of a disomic inheritance at meiosis, where chromosome pairing was restricted to bivalent associations. A hypothesis is presented that a chromosome pairing regulator(s), reported previously in other polyploid broad-leaved fescue species of the <italic>Festuca</italic> subg. <italic>Schedonorus</italic>, is present and functional in <italic>F. pratensis</italic> subsp. <italic>apennina</italic>. It is likely that a common ancestors' genome that carries the chromosome pairing regulator(s) is present in all polyploid broad-leaved fescue species, and its acquisition was a key event that enabled speciation and development of a polyploid series within <italic>Festuca</italic>. Identification of a functional chromosome pairing regulator capable of stabilizing advantageous genome combinations in hybrids within the <italic>Lolium-Festuca</italic> complex would greatly assist in development of stable <italic>Festulolium</italic> cultivars. Its expression within <italic>Festulolium</italic> amphiploid cultivars would assist strategies aimed at climate-proofing productive European grasslands to combat exposures to stress conditions.</p>