Identificação e caracterização de genes candidatos para a tolerância à seca em cafeeiro / Identification and characterization of candidate genes for drought tolerance in coffee

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Coffee is economically important and widely cultivated in Brazil. The cultivated area is well distributed throughout the territory, whereby C. arabica and C. canephora are produced, depending on the region. Usually, drought and adverse temperatures are the major weather constraints to coffee production. The importance of such limitations should increase, according to the recognized global climate changes and also because coffee is being expanded to marginal areas where drought and temperatures are unfavorable and are major limitations for coffee production. Therefore research focused on minimizing the damage caused by abiotic stresses is of fundamental importance for coffee. The goal of this study was to identify candidate genes for drought tolerance in coffee by using different strategies. Initially, differential expression of genes from coffee cDNA libraries of leaves, obtained from plants cultivated under water stress conditions, was evaluated by an in silico analysis using the Coffee Genome Database. In addition, hybridization experiments with cDNA macroarrays of coffee were performed using RNA from leaves of two coffee varieties of C. canephora ,one tolerant to drought stress (Clone 14) and one sensitive (Clone 22), both under normal irrigation (control) and restriction of water. Finally, the differential expression of 29 pre-selected genes with the macroarray experiments were examined using the technique of quantitative real time PCR (qPCR). For qPCR reactions the samples used were leaves of the Clone 22 irrigated and non irrigated and also from three other tolerant clones (Clone 14, 73 and 120 irrigated and not irrigated). Results obtained by the qPCR analysis, showed that most of the genes tested displayed differential expression between the treatments controlled and non irrigated conditions, confirming the data obtained with the macroarrays experiments. All techniques used in this study were efficient in indentifying candidate genes for drought tolerance in coffee, whereby some genes displayed positive results of differential expression by all three methodologies used. The several candidate genes for drought tolerance in coffee, identified in this work, allow a better understanding of the strategies used by the plant to sustain drought periods and such genes, may also be used for biotechnological coffee improvement. Besides, molecular markers associated with drought tolerance in coffee can be developed based on the candidate genes identified aiming at a breeding program based on marker-assisted selection.

ASSUNTO(S)

abiotic stress macroarranjo qpcr macroarray, qpcr agronomia coffea arabica coffea canephora coffea arabica estresses abióticos coffea canephora

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