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Biology subjects

Panaud, O.

Publications and source records attributed to Panaud, O..

2 recordsLinked to original sources

Whole plastid genome-based phylogenomics supports an inner placement of the O. insectifera group rather than a basal position in the rapidly diversifying Ophrys genus (Orchidaceae)

Some lineages of the Orchid genus Ophrys exhibit among the highest diversification rates reported so far. As a consequence of a such intense and rapid evolution, the systematics and the taxonomy of this genus remains unclear. A hybrid assembly approach based-on long- and short-read genomic data allowed us to outperform classical methods to successfully assemble whole plastid genomes for two new Ophrys species: O. aymoninii and O. lutea. Along with three other previously Ophrys plastid genome sequences, we then reconstructed the first whole plastome-based molecular phylogeny including representatives of the three mains recognized Ophrys lineages. Our results support the placement of the O. insectifera clade as sister group of non-basal Ophrys rather than a basal position. Our findings corroborate recent results obtained from genomic data (RAD-seq and transcriptomes) but contrast with previous ones. These results therefore confirm that molecular phylogenetic hypotheses based on a limited number of loci (e.g. nrITS, matK, rbcL) may have provided a biased picture of phylogenetic relationships within Ophrys and possibly other plant taxa.

evolutionary biology↗

The replicative amplification of MITEs and their impact on rice trait variability

Transposable elements (TEs) are a rich source of genetic variability. Among TEs, Miniature Inverted- repeat Transposable Elements (MITEs) are of particular interest as they are present in high copy numbers in plant genomes and are closely associated with genes. MITEs are deletion derivatives of class II transposons, and can be mobilized by the transposases encoded by the latters through a typical cut-and-paste mechanism. However, this mechanism cannot account for the high copy number MITEs attain in plant genomes, and the mechanism by which MITEs amplify remains elusive. We present here an analysis of 103,109 Transposon Insertion Polymorphisms (TIPs) in 1,059 O. sativa genomes representing the main rice population groups. We show that an important fraction of MITE insertions has been fixed in rice concomitantly with rice domestication. However, another fraction of MITE insertions is present at low frequencies. We performed MITE TIP-GWAS to study the impact of these elements on agronomically important traits and found that these elements uncover more trait associations than SNPs on important phenotypes such as grain width. Finally, using SNP-GWAS and TIP-GWAS we provide evidences of the replicative amplification of MITEs, suggesting a mechanism of amplification uncoupled from the typical cut-and-paste mechanism of class II transposons.

molecular biology↗