In many plants, Dihydroflavonol-4-Reductase(DFR) and Leucoanthocyanidin Reductase(LAR) are two key enzymes in antibacterial material catechin biosynthesis. However, whether the two enzymes have effects on synthesis way of catechin is not clear in poplar. In order to study the differential expression of DFR gene and LAR gene related to the way of catechin synthesis after inoculated with Lonsdalea quercina subsp. populi, and to explore the relationship between two genes and catechins synthesis, quantitative r...