Towards the Paspalum full genome characterization: from drawbacks to benefits?

ORTIZ JPA

Zavalla

Workshop; In-house seminars: Mechanisms operating to promote the transition from sexuality to apomixis in the Gramineae; 2017

Grupo Apomixis Rosario

The main objective of our research is to provide the complete genome sequence of Paspalum notatum Flügge, including annotation of predicted genes, repetitive elements, assignment functional categories to genes, resolve the genomic structure of the P. notatum ACL and propose hypotheses for functional role in apomictic reproduction. After more than 10 years of reseach we know that apomixis is controlled by a single locus with distorted segregation ratio, which is often large and recalcitrant to recombination. Tetraploid races are highly heterozygous and showed polysomic inheritance. Anaphase I of apomictic strains have meiotic abnormalities that are transmitted to the apomictic progenies. FISH and 5-methylcytosine analyses showed that ACL is located on an heterocromatic region highly methylated and possibly hemyzigous. Highly repetitive as well as protein-coding sequences have been identified within the ACL of both P. notatum and P. simplex. Only a small fraction (3,5 - 350 Kbp) of the ACL could be characterized. A group of genes mapping at the ACL were identified and are under analysis. Under a current project funded by EU we are working on produce DNA sequencing raw data from a diploid genotype with low expression of apomixis. We are intenting to draft of genomic sequence of a diploid genotype and assemblying the ACL from a resequencing a fully apomictic tetraploid genotype. Genomic sequence annotation of genes included in ACL will be used for indentifying kew genes associated with the sift from sexuality to apomixis. As a results we have generated some 89 Gpb of data from 2x P. notatum genome for sequence analysis and candidate?s gene structure characterization. Long sequence reads are underway by using the MinION Nanopore technology and we expect to have the first results in the next few months. The assembly of the complete 2x P. notatum genome will carried out by combining both Illumina and Nanopere reads. Combining genetic, genomic and transcriptomic information will help us to disclose the molecular structure of the ACL of P. notatum.