Analysis on the Role of Phenylpropanoid Metabolism in the Pinus pinaster-Botrytis cinerea Interaction

The interaction between maritime pine (Pinus pinaster) and the necrotrophic pathogen Botrytis cinerea was addressed at the level of phenylpropanoid metabolism using a suspension cell model system. HPLC-DAD analysis revealed the presence of several phenolic compounds, including derivatives of epicatechin, caffeoylquinic acid and glycosylated quercetin. However, challenged cells evidenced a reduction in total soluble phenolics and a decrease in the lignin content of cells. Key phenylpropanoid metabolism genes Pal and Chs were isolated after screening a P. pinaster cDNA library. Expression analysis evidenced a downregulation of Pal transcripts. Chs transcripts were observed in P. pinaster needles but not in suspension cells. With regard to the P. pinaster–B. cinerea interaction, results indicate that elicited cells downregulate phenylpropanoid metabolism, which suggests that systemic acquired resistance is not induced after challenging with this necrotrophic pathogen.