Biotechnological and genomic tools for the improvement of weeping lovegrass (Eragrostis curvula)

VIVIANA ECHENIQUE; PESSINO, S.; DIAZ, M; LUCIANI, G.; SELVA, J.P.; ZAPPACOSTA, D.; CERVIGNI, G.; MEIER, M.; GARBUS I; CARDONE, S.; SPANGENBERG, G.

San Diego (California) USA

Conferencia; XVII Plant and Animal Genome Conference; 2009

Eragrostis curvula has potential to colonize marginal production areas due to its low input costs, fast growth and high biomass production in poor soils and dry environments. It covers 800,000 has in Argentina. We are focused on molecular breeding of weeping lovegrass by using genomic and biotechnological tools including an euploid series for studying genetic and epigenetic changes related to ploidy and reproductive mode, calose deposition studies for differentiating between apomictic and sexual types, cDNA libraries for genome mapping, transcriptome analysis and gene identification, and molecular markers for cultivar differentiation. From our cDNA libraries, 12,300 ESTs were clustered and assembled, 8,864 unigenes were identified and 80 % was functionally assigned. Based on pairwise in silico substractions 207 differentially expressed genes were identified related to ploidy and/or reproductive mode including genes involved in cell cycle regulation, protein turnover, DNA and RNA synthesis and stress response. These genes were mostly downregulated in sexual diploids and apomictic tetraploids but upregulated in sexual tetraploids suggesting that a transcriptome repatterning process is needed to maintain sexuality in polyploids and apomixis is probably the consequence of a failure in this reppaterning process. Also, we identified sequences of CCoAOMT and R2R3MYB transcription factors involved in lignin biosynthesis. These sequences are suitable candidates to improve weeping lovegrass nutritional quality. Therefore, we are developing regeneration, selection and transformation protocols to evaluate the roles of these candidate genes related to apomixis and lignin biosynthesis. Molecular markers were also identified (254 SSRs and 190 SNPs/indels). These markers will be useful tools for MAS.