Enhancement of the natural disease resistance of potatoes by chemicals

ANDREU A. B; GUEVARA, M. G.; WOLSKI, E. A.;; DALEO, G. R; D. O. CALDIZ.

San Carlos de Bariloche. Argentina.

Congreso; XXXIX REUNION ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIONES EN BIOQUIMICA Y BIOLOGIA MOLECULAR (SAIB).; 2003

SOCIEDAD ARGENTINA DE INVESTIGACIONES EN BIOQUIMICA Y BIOLOGIA MOLECULAR (SAIB).

The mechanism involved in systemically induced resistance (SIR) can be induced nonspecifically in susceptible plants. In response to pathogens the natural defense mechanism of plants includes the production of lignin, phytoalexins and the induction of plant enzymes. The aim of this investigation was to study the induction of SIR mediated by the chemical activator DL-3-aminobutiric acid (BABA) and the fungicide Fosetyl-aluminium (Aliette) in processing potato cultivars with different levels of resistance against Phytophthora infestans. For the chemical induction of resistance, foliage of potato cultivars were sprayed with BABA, Aliette or water (as a control) and after three days the foliage was inoculated with P. infestans. After several days, the following parameters were evaluated: development of disease symptoms in foliage, protein level of several enzymes, and phenols and phytoalexin content in post-harvest tuber samples. After application of the chemicals the highest level of protection against P. infestans in foliage was observed at early stages of the development of the crop (30 days after sprouting). An increase in the resistance against Late Blight was also detected in plant tubers or post-harvest. There was also an increase in protein level of ß1-3 glucanase and aspartic protease, as well as in phenols and phytoalexins content in potato tuber disks post infection. This effect seemed to persist throughout the whole of plant. This treatment may offer the possibility of controlling both foliage and tuber blight and could have a major impact in reducing overwinter survival of P. infestans in tubers.