Un sistema di trasporto del foraggio da insilare in zone montane

<div><p>Background</p><p><i>Paspalum dilatatum</i> Poir. (common name dallisgrass) is a native grass species of South America, with special relevance to dairy and red meat production. <i>P. dilatatum</i> exhibits higher forage quality than other C4 forage grasses and is tolerant to frost and water stress. This species is predominantly cultivated in an apomictic monoculture, with an inherent high risk that biotic and abiotic stresses could potentially devastate productivity. Therefore, advanced breeding strategies that characterise and use available genetic diversity, or assess germplasm collections effectively are required to deliver advanced cultivars for production systems. However, there are limited genomic resources available for this forage grass species.</p><p>Results</p><p>Transcriptome sequencing using second-generation sequencing platforms has been employed using pooled RNA from different tissues (stems, roots, leaves and inflorescences) at the final reproductive stage of <i>P. dilatatum</i> cultivar Primo. A total of 324,695 sequence reads were obtained, corresponding to c. 102 Mbp. The sequences were assembled, generating 20,169 contigs of a combined length of 9,336,138 nucleotides. The contigs were BLAST analysed against the fully sequenced grass species of <i>Oryza sativa</i> subsp. <i>japonica</i>, <i>Brachypodium distachyon</i>, the closely related <i>Sorghum bicolor</i> and foxtail millet (<i>Setaria italica</i>) genomes as well as against the UniRef 90 protein database allowing a comprehensive gene ontology analysis to be performed. The contigs generated from the transcript sequencing were also analysed for the presence of simple sequence repeats (SSRs). A total of 2,339 SSR motifs were identified within 1,989 contigs and corresponding primer pairs were designed. Empirical validation of a cohort of 96 SSRs was performed, with 34% being polymorphic between sexual and apomictic biotypes.</p><p>Conclusions</p><p>The development of genetic and genomic resources for <i>P. dilatatum</i> will contribute to gene discovery and expression studies. Association of gene function with agronomic traits will significantly enable molecular breeding and advance germplasm enhancement.</p></div

Frequency histograms showing the distribution of contigs compared to sequence read length (A), the distribution of the number of reads per contig (B), and distribution of singletons compared to read length (bp) (C).

<p>Frequency histograms showing the distribution of contigs compared to sequence read length (A), the distribution of the number of reads per contig (B), and distribution of singletons compared to read length (bp) (C).</p

Sequence analysis of the generated <i>P. dilatatum</i> contigs compared to the reference grass genomes.

<p>The <i>P. dilatatum</i> contigs were compared using BLASTn with an e value threshold of 10⁻¹⁰ and significant matches were identified and totaled and presented as a Venn diagram.</p

Assignment of putative function and gene ontology (GO) annotations to <i>P. dilatatum</i> sequence contigs based on Biological process classification (A), Molecular function (B) and Cellular components (C).

<p>Assignment of putative function and gene ontology (GO) annotations to <i>P. dilatatum</i> sequence contigs based on Biological process classification (A), Molecular function (B) and Cellular components (C).</p

Details of SSR molecular markers from <i>P. dilatatum</i> validated as polymorphic within the current study.

<p>Details of SSR molecular markers from <i>P. dilatatum</i> validated as polymorphic within the current study.</p