De novo transcriptome sequencing and assembly for studying apomixis- related gene expression in Eragrostis curvula

GARBUS INGRID; ROMERO JOSE; SELVA JUAN PABLO; ECHENIQUE VIVIANA C

Iguazu Falls

Congreso; 11th International Congress of Plant Molecular Biology; 2015

Eragrostis curvula represents an important cultivated forage resource in semiarid regions which reproduce by pseudogamous diplosporous apomixis. We previously produced an EST collection from panicles of a series of genetically related E. curvula lines. In this work, next generation sequencing technologies were used to increase the transcriptome sequences available aiming to generate an useful resource for gene annotation and discovery of this species. Thus, four inflorescence cDNA libraries, two from the apomictic cultivar Tanganyika and two from the sexual cultivar OTA, were generated though Roche 454 pyrosequencing, leading to 2,617,197 raw reads with an average length ~364 bp. Due to the lack of E. curvula whole-genome sequence, a de novo assembly of high quality clean reads into transcripts was conducted, leading to 63,763 contigs, that were assembled into 49,568 isotigs, i.e., the bioinformatical equivalent to unique transcripts, that were further grouped into 25,186 isogroups, potentially reflecting multiple splice variants. Near 90% of the isotigs were annotated through BLASTX against nr and pfam protein databases. Gene ontology (GO) and KEGG pathway mapping analysis revealed various functional genes related to diverse biological functions and processes. The differential expression analysis revealed that ~3000 and ~6000 transcripts were differentially found in libraries constructed from sexual and apomictic inflorescences, respectively. Such data deserves a deeply analysis since the search of candidate genes to be involved in the reproductive mode expression provided little successes. This study provides a comprehensive insight into the transcriptome of E. curvula and a way for exploration and understanding of the reproductive behavior regulation of this species.