Phenylpropanoid pathway genes and secondary metabolites are affected

HENRIQUEZ M. A.; WOLSKI E.A.; MOLINA O.; ADAMS L.R.; ANDREU A.B; DAAYF F.

Winnipeg MB. CANADA

Congreso; Annual meeting of the Canadian Phytophological Society; 2009

Canadian Phytophological Society

Late blight, caused by Phytophthora infestans (Mont) de Bary is a major disease of potato. Potato susceptibility to P. infestans has been suggested as an outcome to potato defense suppression by P. infestans glucans released only by compatible races of the oomycete under in vitro conditions. Some glucans are able to suppress phytoalexin accumulation and induction of glucanases. The objective of this investigation was to analyze in a whole plant (in vivo), the effects of glucans from race C (mating type A2), the elicitor eicosapentanoic acid (EPA) and P. infestans isolates on the accumulation of secondary compounds and defense related transcripts in the susceptible and the partially resistant potato cultivars Russet Burbank and Defender. respectively. For this purpose, we used HPLC and RT-PCR analysis. Potato cultivars inoculated with P. infestans accumulated different secondary metabolites. Glucans from race C, added after EPA dramatically suppressed the accumulation of secondary compounds in Russet Burbank and Defender, compared with the glucans alone. In addition, the glucans added after EPA enhanced the symptoms of late blight in Russet Burbank inoculated with US-8, with a dramatic reduction in the accumulation of secondary metabolites. However, in Defender inoculated with US-8 treated with the glucans added after EPA, the accumulation of secondary metabolites was also reduced, while late blight symptoms were not detected. The RT-PCR analysis showed the suppression of different genes in the phenylpropanoids pathway, the terpenoids pathway and signaling genes. Finally the analysis of some genes using RT-PCR showed high similarity with the HPLC analysis of putative final products and the Potato-P. infestans interaction.