The first complete chloroplast genome of the Genistoid legume Lupinus luteus: evidence for a novel major lineage-specific rearrangement and new insights regarding plastome evolution in the legume familyReport as inadecuate




The first complete chloroplast genome of the Genistoid legume Lupinus luteus: evidence for a novel major lineage-specific rearrangement and new insights regarding plastome evolution in the legume family - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 ECOBIO - Ecosystèmes, biodiversité, évolution Rennes 2 GEF - Plateforme Génomique Environnementale et Fonctionnelle

Abstract : † Background and Aims To date chloroplast genomes are available only for members of the non-protein amino acidaccumulating clade NPAAA Papilionoid lineages in the legume family i.e. Millettioids, Robinoids and the -inverted repeat-lacking clade-, IRLC. It is thus very important to sequence plastomes from other lineages in order to better understand the unusual evolution observed in this model flowering plant family. To this end, the plastome of a lupine species, Lupinus luteus, was sequenced to represent the Genistoid lineage, a noteworthy but poorly studied legume group. † Methods The plastome of L. luteus was reconstructed using Roche-454 and Illumina next-generation sequencing. Its structure, repetitive sequences, gene content and sequence divergence were compared with those of other Fabaceae plastomes. PCR screening and sequencing were performed in other allied legumes in order to determine the origin of a large inversion identified in L. luteus. † Key Results The first sequenced Genistoid plastome L. luteus: 155 894 bp resulted in the discovery of a 36-kb inversion, embedded within the already known 50-kb inversion in the large single-copy LSC region of the Papilionoideae. This inversion occurs at the base or soon after the Genistoid emergence, and most probably resulted from a flip-flop recombination between identical 29-bp inverted repeats within two trnS genes. Comparative analyses of the chloroplast gene content of L. luteus vs. Fabaceae and extra-Fabales plastomes revealed the loss of the plastid rpl22 gene, and its functional relocation to the nucleus was verified using lupine transcriptomic data. An investigation into the evolutionary rate of coding and non-coding sequencesamong legume plastomes resulted in the identification of remarkably variable regions. †Conclusions This study resulted in the discovery of a novel, major 36-kb inversion, specific to the Genistoids. Chloroplast mutational hotspots were also identified, which contain novel and potentially informative regions for molecular evolutionary studies at various taxonomic levels in the legumes. Taken together, the results provide new insights into the evolutionary landscape of the legume plastome.

Keywords : Lupinus luteus European yellow lupine legume Genistoid clade chloroplast genome evolution structural plastid rearrangement 36-kb inversion inverted repeats flip-flop recombination lineage-specific marker functional gene transfer Papilionoidae repeated plastid sequences sequence divergence plastome hotspots Fabaceae phylogeny





Author: Guillaume E. Martin - Mathieu Rousseau-Gueutin - Solenn Cordonnier - Oscar Lima - Sophie Michon-Coudouel - Delphine Naquin - Juli

Source: https://hal.archives-ouvertes.fr/



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