Resistência à ferrugem do cafeeiro: mapeamento genético, físico e análise da expressão gênica em resposta a infecção de H. vastatrix / Coffea leaf rust: genetic, physical mapping and analysis of the gene expression in response to infection the H. vastatrix

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The coffee leaf rust it is caused by the biothrofic fungus Hemileia vastatrix is one diseases that more it causes economical damages. The coffee breeding for obtaining for resistance plants it is slow and the moleculars studies of identification for resistance genes to H. vastatrix are still few informative. This study had as objective to obtain information structural and functional genetics of this incompatible interaction. A population UFV F2421-4 was evaluated (Hibrido de Timor x Catuaí) with 224 coffee plants segregants for a gene for resistance for H. vastatrix race II. It was obtained a genetic map saturated with 25 AFLP markers that made possible the elaboration of the genetic map of high density with 6 SCARs markers delimiting a chromosomal region of 9,45 cM and flanking to resistance gene the 0.7 and 0.9 cM. The SCARs markers are first available tools it is constituted for strategies to obtain the resistance for coffee leaf rust by molecular markers assisted selection. The genetic mapping SCARs markers guided the construction of the contig with 4.7 cM and ~360kb, obtained of the ordering of 5 clones BAC that contained simultaneous the presence of two markers. They were isolated two clones BAC bearers of the markers that flanking the resistance gene into region ~120 kb. The obtaining of the contig will make possible the cloning of the first resistance gene the coffee leaf rust. In the study of genic expression were identified 108 Transcripts- Derived Fragments (TDF) through the cDNA-AFLP technique, being 93 of this similar with genes involved in biological processes of metabolism, growth, genic activation, signalling, defense response and protein controlled degradation. Of these, 21 TDFs were selected potentially involved in the signalling and defense response for the expression analysis for Real Time PCR. The selected genes are activated 12 h pósinoculation. Those classified as having involved in the signalling presented more expression 24 h pós-inoculation and for defense, increased the expression exponentially up to 72 h. Similar TDFs to signalling genes, the largest expression level was observed for a gene NBSLRR and, for the defense, a gene that codifies for pathogenesis-related protein PR5 (similar to Thaumatin). TDF NBS-LRR is a gene candidate of the recognition for elicitor of pathogen and PR5 can have an important ativity in the defense in coffee plant. The identification gene differentility expressed is constituted in an important information to understand the molecular mechanism of resistance for coffee leaf rust.

ASSUNTO(S)

ferrugem do cafeeiro contig tdfs signalling genes genes de sinalização resposta de defesa coffee leaf rust contig tdfs fisiologia de plantas cultivadas defense response

ACESSO AO ARTIGO

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