Abstract Detail

Genomics / Proteomics

Spoelhof, Jonathan [1], Chester, Micahel [2], Rodriguez, Roseana [1], Geraci, Blake [1], Heo, Kweon [3], Mavrodiev, Evgeny [4], Soltis, Douglas E [5], Soltis, Pamela  S. [6].

Karyotypic Diversity and Pollen Viability in Resynthesized allopolyploids Tragopogon mirus and T. miscellus..

Polyploidy is an important mechanism of diversification and genome evolution among eukaryotes, particularly in ferns and flowering plants. Allopolyploidy (genome duplication in association with hybridization between species) accounts for roughly one-half of recent polyploidization events. Research performed on two recently formed allopolyploid species, Tragopogon mirus and Tragopogon miscellus (Asteraceae), has illuminated many features of early allopolyploid evolution (ca. 40 generations after genome duplication). Curiously, these species are both highly fertile and karyotypically diverse, but the trajectory of these traits throughout the neopolyploid and nascent polyploid stages is poorly understood. In this study, we used genomic in situ hybridization (GISH) to determine the rate at which karyotypic diversity develops in resynthesized neopolyploid T. mirus and T. miscellus during the first few generations after whole-genome duplication (WGD). We also used lactophenol blue staining to measure pollen viability (as a proxy for fertility) to determine whether neopolyploid T. mirus and T. miscellus show a typical decrease in fertility, and whether that fertility changes quickly over time. We observed widespread karyotypic variation among resynthesized polyploids, including aneuploidy, compensated aneuploidy, and chromosomal translocations. By the fourth generation after WGD, the karyotypic diversity of resynthesized T. mirus and T. miscellus did not differ largely from natural populations. The mean pollen fertilities of resynthesized T. mirus and T. miscellus were significantly lower than that of natural allopolyploids at each generation. The mean pollen viability of resynthesized T. mirus increased slightly over four generations, while resynthesized T. miscellus remained stable. In conclusion, synthetic lines of both polyploid species show dramatic increases in karyotypic diversity within the first four generations following WGD, which suggests that the karyotypic variation among natural populations arose quite early during their establishment. Resynthesized T. mirus and T. miscellus also possess low pollen viability which may take longer (10 generations) to reach levels that are observed in naturally occurring T. mirus and T. miscellus.

1 - University of Florida, Biology - Botany, Florida Museum of Natural History–Dickinson Hall, 1659 Museum Road, Gainesville, FL, 32611, USA
2 - Royal Botanic Gardens, Kew, Natural Capital and Plant Health, Jodrell Laboratory, Kew, Richmond, Surrey, TW9 3AE, UK
3 - Kangwon National University, Department of Applied Plant Sciences, Chuncheon, Gangwon, 200-701, Korea
4 - University Of Florida, Florida Natural History Museum, Florida Museum Of Natural History PO Box 117800, Gainesville, FL, 32611-7800, United States
5 - University of Florida, Florida Museum of Natural History, Gainesville, FL, 32605, USA
6 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964

Keywords:
polyploidy
chromosomal rearrangement
Tragopogon
fertility.

Presentation Type: Oral Paper
Session: 27, Genomics & Proteomics II
Location: 105/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 4:15 PM
Number: 27011
Abstract ID:444
Candidate for Awards:Margaret Menzel Award