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Abstract Detail

Genomics / Proteomics

Shan, Shengchen [1], Soltis, Douglas [2], Soltis, Pamela  S. [3].

Genomic Consequences of Reciprocal Polyploidization in Tragopogon.

Polyploidy, or whole-genome duplication (WGD), is a major evolutionary force in plant evolution and is widespread throughout the green plant clade. The dynamic nature of polyploid genome evolution might explain the evolutionary novelty and long-term persistence of these plants. Many studies have demonstrated that multiple origins of polyploids are the rule, not the exception. Yet we know little about the genetic and genomic consequences of reciprocal formation of allopolyploids—a phenomenon that may be much more common than currently realized. Tragopogon (Asteraceae), from western North America, is an outstanding natural system for polyploidy research and provides a unique opportunity to examine the evolutionary process after recent and repeated polyploidization. The repeatedly formed allotetraploid Tragopogon miscellus (2n=24) is only about 80 years old (~40 generations in this biennial plant species). Interestingly, T. miscellus has formed reciprocally in nature. Furthermore, the reciprocally formed T. miscellus has two inflorescence morphologies: those tetraploids with T. dubius (2n=12) as maternal parent have inflorescences with long ligules, and those with T. pratensis (2n=12) as maternal parent have inflorescences with short ligules. To investigate the genetic control of these morphological differences, RNA was extracted from both morphs, with three biological replications each. Illumina Nextseq (paired-end sequencing) was used to characterize the pattern of differentially expressed genes between reciprocally formed T. miscellus. After adapter and quality trimming, about 25 million reads remained for each sample, and the average read length was about 140 bp. Trinity was used for de novo assembly, and after filtering poorly supported contigs, 276,039 contigs were generated (N50 is 722 bp). By applying abundance estimation using RSEM, and differential expression analysis using edgeR, 536 differentially expressed contigs were found between the two morphs (4-fold differential expression; FDR<=0.001), in which 290 contigs were highly expressed in short-liguled T. miscellus and 246 contigs were highly expressed in long-liguled T. miscellus. Annotation of those differentially expressed genes is still ongoing. These analyses will help us to unravel the mechanisms controlling morphological differences between reciprocally formed allopolyploid populations.

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1 - University of Florida, Plant Molecular and Cellular Biology Program, 322 University Village South, Apartment 6, Gainesville, Florida, 32603-2041, United States
2 - University of Florida, Dept. of Biology, 1659 Museum Road, Gainesville, Florida, 32611, United States
3 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964

Tragopogon miscellus
Reciprocal cross.

Presentation Type: Poster
Session: P, Genomics/Proteomics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PGP005
Abstract ID:616
Candidate for Awards:Genetics Section Poster Award

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