Genetic and molecular studies in Panicum maximum: genetic and molecular mapping and transcriptome analysis via RNA-seq

Author(s)

Guilherme Toledo Silva

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2014-02-28

Examining board members

Anete Pereira de Souza; Gabriel Rodrigues Alves Margarido; Sérgio Furtado dos Reis; Patrícia Menezes Santos; Flavio Antonio Maës dos Santos

• Advisor: Anete Pereira de Souza; Liana Jank

Abstract

In Brazil, livestock feeding is mainly based on cultivated pastures. Panicum maximum Jacq., also known as capim-colonião, figures among the most cultivated tropical forage plants in brazilian pastures, which are established with exotic cultivars of clonal reproduction, leading to monoculture, and consequently offering serious risks to associated production systems. One possible solution to monoculture falls on new cultivars releases, throught breeding programs, diversificating livestock pastures in Brazil. The work presented here had an objective of elucidate some basic aspects regarding the genetics and molecular biology of P. maximum. First, we conducted a de novo assembly and analysis of leaf transcriptome, throught massive parallel cDNA sequencing (RNA-seq), resulting in 38.192 unigenes, which were annotated in different databases. Genes related to C4 metabolism and lignocellulose synthesis are valuable resource to breeding programs and were identified among assembled transcripts. Thus, several putative molecular markers were located in unigenes: 5.035 microsatellites (SSR) motifs and 346.456 single nucleotide polymorphism (SNP) positions. Also, we developed 131 new genomic and expressed SSR markers for P. maximum. These markers were used with 43 published SSR markers to develop a genetic map. A segregating F1 population were used for such, hybrids of S10 (sexual genotype) and Mombaça (apomictic genotype) crossing. Linkage maps covered 672,2 cM and 802,2 cM of parentals genomes respectively, using 88 and 96 markers each. Results presented in this work contributes to P. maximum and tropical grasses related research and breeding programs (AU)