Improvement of the banana "Musa acuminata" reference sequence using NGS data and semi-automated bioinformatics methods.
Guillaume Martin, Franc-Christophe Baurens, Gaëtan Droc, Mathieu Rouard, Alberto Cenci, Andrzej Kilian, Alex Hastie, Jaroslav Doležel, Jean-Marc Aury, Adriana Alberti, Françoise Carreel, Angélique D'Hont
Author Information
Guillaume Martin: CIRAD (Centre de coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, TA A-108/03, Avenue Agropolis, F-34398, Montpellier, cedex 5, France.
Franc-Christophe Baurens: CIRAD (Centre de coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, TA A-108/03, Avenue Agropolis, F-34398, Montpellier, cedex 5, France.
Gaëtan Droc: CIRAD (Centre de coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, TA A-108/03, Avenue Agropolis, F-34398, Montpellier, cedex 5, France.
Mathieu Rouard: Bioversity International, Parc Scientifique Agropolis II, 34397, Montpellier, Cedex 5, France.
Alberto Cenci: Bioversity International, Parc Scientifique Agropolis II, 34397, Montpellier, Cedex 5, France.
Andrzej Kilian: Diversity Arrays Technology, Yarralumla, Australian Capital Territory, 2600, Australia.
Alex Hastie: BioNano Genomics, 9640 Towne Centre Drive, San Diego, CA, 92121, USA.
Jaroslav Doležel: Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Šlechtitelů 31, CZ-78371, Olomouc, Czech Republic.
Jean-Marc Aury: Commissariat à l'Energie Atomique (CEA), Institut de Genomique (IG), Genoscope, 2 rue Gaston Cremieux, BP5706, 91057, Evry, France.
Adriana Alberti: Commissariat à l'Energie Atomique (CEA), Institut de Genomique (IG), Genoscope, 2 rue Gaston Cremieux, BP5706, 91057, Evry, France.
Françoise Carreel: CIRAD (Centre de coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, TA A-108/03, Avenue Agropolis, F-34398, Montpellier, cedex 5, France.
Angélique D'Hont: CIRAD (Centre de coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, TA A-108/03, Avenue Agropolis, F-34398, Montpellier, cedex 5, France. dhont@cirad.fr.
BACKGROUND: Recent advances in genomics indicate functional significance of a majority of genome sequences and their long range interactions. As a detailed examination of genome organization and function requires very high quality genome sequence, the objective of this study was to improve reference genome assembly of banana (Musa acuminata). RESULTS: We have developed a modular bioinformatics pipeline to improve genome sequence assemblies, which can handle various types of data. The pipeline comprises several semi-automated tools. However, unlike classical automated tools that are based on global parameters, the semi-automated tools proposed an expert mode for a user who can decide on suggested improvements through local compromises. The pipeline was used to improve the draft genome sequence of Musa acuminata. Genotyping by sequencing (GBS) of a segregating population and paired-end sequencing were used to detect and correct scaffold misassemblies. Long insert size paired-end reads identified scaffold junctions and fusions missed by automated assembly methods. GBS markers were used to anchor scaffolds to pseudo-molecules with a new bioinformatics approach that avoids the tedious step of marker ordering during genetic map construction. Furthermore, a genome map was constructed and used to assemble scaffolds into super scaffolds. Finally, a consensus gene annotation was projected on the new assembly from two pre-existing annotations. This approach reduced the total Musa scaffold number from 7513 to 1532 (i.e. by 80%), with an N50 that increased from 1.3 Mb (65 scaffolds) to 3.0 Mb (26 scaffolds). 89.5% of the assembly was anchored to the 11 Musa chromosomes compared to the previous 70%. Unknown sites (N) were reduced from 17.3 to 10.0%. CONCLUSION: The release of the Musa acuminata reference genome version 2 provides a platform for detailed analysis of banana genome variation, function and evolution. Bioinformatics tools developed in this work can be used to improve genome sequence assemblies in other species.
