Séminaire IBIP
Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Jeudi 11 octobre 2012
Amphi 206 (Cœur d’Ecole) à 14h

Plant and animal genome structural, functional and evolutionary plasticity

Jérôme Salse
UMR INRA-UBP 1095 GDEC, Clermont-Ferrand – www4.clermont.inra.fr/umr1095/ppav – e-mail: jsalse@clermont.inra.fr

During the last decade, technological improvements led to the development of large sets of genomic resources permitting the emergence of high-resolution comparative genomic studies in both plant and animal lineages. In an attempt to unravel the structure and evolution of their ancestral founder genomes, we have re-assed the synteny and duplications of plant and animal genomes to identify and characterize paleo- and neo-duplications. We combined the data on the intra-genomic duplications with those on the colinear blocks that allowed us to propose a model in which the plant and animal genomes have evolved from a common ancestors with respectively a basic number of 5 to 13 chromosomes through whole genome duplications (i.e. paleopolyploidization) and translocations followed by lineage specific segmental duplications, chromosome fusions and translocations (Murat et al. 2012, Salse 2012). Based on the comparison of the plant and animal genome paleohistory, some major differences are unveiled in (i) evolutionary mechanisms (i.e. polyploidization processes), (ii) genome conservation (i.e. coding and non-coding sequence maintenance), and (iii) modern genome architecture (i.e. genome organization including repeats expansion and contraction phenomena). These data demonstrates how extant animal and plant genomes are the result of inherently different rates and modes of genome evolution resulting in relatively stable animal and much more dynamic and plastic plant genomes. In order to investigate the plant genome plasticity deriving from surimposed rounds of polyploidies, we characterized Angiosperm ancestors comprising 5/7 ancestral chromosomes with 10000 protogenes providing a new reference for the plant chromosomes and new insights into their ancestral relationships that have led to arrange their chromosomes into concentric ‘crop circles’ of synteny blocks (Salse 2012 ). The established plant ancestor genome structure in term of chromosome structure and gene content offered the opportunity to study the impact of evolutionary shuffling events such as polyploidizations on (i) genome structure (i.e. mechanism driving the diploidization process), (ii) genome function (i.e. polyploidization resistant vs sensitive genes), (iii) genome expression (i.e. role of epigenetics on neo/sub-functionalization process), (iv) trait elaboration (i.e. conserved vs lineage specific traits), that will be discussed in details (Quraishi et al. 2011ab, Pont et al. 2011).

Quraishi UM, Murat F, Abrouk M, Pont C, Confolent C, Oury FX, Ward J, Boros D, Gebruers K, Courtin C, Bedos Z, Saulnier L, Guillon F, Balzergue S, Shewry P, Feuillet C, Charmet G, Salse J (2011a) Meta‐genomics analysis of the grain dietary fiber content in bread wheat. Functional & Integrative Genomics 11(1):71‐83

Quraishi UM, Abrouk M, Murat F, Pont C, Foucrier S, Desmaizieres G, Confolent C, Rivière N, Charmet G, Paux E, Murigneux A, Guerreiro L, Lafarge S, Le Gouis J, Feuillet C and Salse J (2011b) Cross‐genome map based dissection of a nitrogen use efficiency ortho‐metaQTL in bread wheat unravels concerted cereal genome evolution. Plant Journal 65(5):745‐56

Pont C, Murat F, Confolent C, Balzergue S, Salse J (2011) RNA‐seq in grain unveils fate of neo‐ and paleopolyploidization events in bread wheat (Triticum aestivum L.). Genome Biol. 12(12):R119

Salse J (2012) In silico archeogenomics unveils modern plant genome organization, regulation and evolution. Current Opinion in Plant Biology

Murat F, Van de Peer Y, Salse J (2012) Decoding plant and animal genome plasticity from differential paleo ‐ evolutionary patterns and processes. Genome Biology & Evolution

Contact : Françoise Gosti

Contacts IBIP :
Sabine Zimmermann
Philippe Nacry
Christine Granier
Chantal Baracco