PLPKI as a potential biochemical marker involved in horizontal resistance to Phytophthora infestans

FELDMAN M.L.; KORGAN S; HUARTE M.A.; DALEO GR; ANDREU AB

Puerto Madryn Argentina

Congreso; Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

PL-P10PLPKI AS A POTENTIAL BIOCHEMICAL MARKERINVOLVED IN HORIZONTAL RESISTANCE TO P.infestansFeldman ML1, Korgan S1, Huarte MA2, Daleo GR1, Andreu AB11IIB, CONICET-UNMdP, Mar del Plata, Argentina; 2 EEA INTABalcarce, Balcarce, Argentina. E-mail:Late Blight (LB) is the main disease that affects potatoes around theworld. Due to the unavailability of an efficient chemical controlmethod, the use of genetic resistance to LB represents a safestrategy. Two forms of genetic resistance to Phytophthora infestans(Pi) in potato species have been described, vertical resistance (VR)or horizontal resistance (HR). VR is characterized by interactionsbetween products of dominant R genes in the host andcorresponding avirulence genes in the pathogen. In contrast, HR isassumed to be multiple gene-based. This type of resistance isdurable and thus commercially more attractive than VR.In our lab, we have isolated and characterized a serine proteinaseinhibitor specific for proteinase K (PLPKI) which was induced inpotato leaves of a cultivar with a high degree of HR upon infectionwith Pi. The aim of the present work was to establish a correlationbetween the degree of HR with PLPKI accumulation in Solanumtarijense clones (tjr), which are part of the Argentinean PotatoBreeding Program. Both total proteinase K inhibitor activity andwestern blot analysis with an antibody raised against PLPKIshowed the highest accumulation of PLPKI in a tjr clone which hasbeen described as highly resistant. These results suggest thatPLPKI can be potentially used as a biochemical marker to assistbreeders in the selection of HR cultivars.