Rezisztencia-formák felhasználása a növények immunizálására és ellenálló, transzgenikus növények nemesítésére = Application of resistance forms for immunizing plants against pathogenic infections and for breeding disease resistant transgenic crops

A ROS (pl. O2.-, H2O2) felhalmozodasa a biotrof patogenek altal okozott betegsegek ellen idez elő rezisztenciat, a magas szintű antioxidans kapacitas pedig tuneti rezisztenciat idez elő nekrotrof korokozok ellen. - Sikerult olyan dohany- es burgonyavonalakat előallitanunk, amelyek egy szuperoxid-dizmutaz (SOD) es katalaz (CAT) antioxidans transzgent tartalmaznak. - Az antioxidans kapacitas fokozasat mas uton is elertuk. Ha kis koncentracioju H2O2-vel kezeltuk a dohanyokat, ezek antioxidans kapacitasa jelentősen fokozodott. Az "immunizalo hatas" miatt tuneti rezisztenciat mutattak virus-, bakterium- es gombakorokozok ellen. - A nem-gazda rezisztencia lenyegenek megismerese erdekeben 18 gazdanoveny/patogen kapcsolatot elemeztunk a O2.- akkumulacioja szempontjabol. A fogekony gazda/patogen kapcsolatokban nincs felhalmozodas, a gazda-rezisztens novenyekben kb. 48 oraval a fertőzes utan a O2.- felhalmozodik, es a hiperszenzitiv reakcio (HR) is kialakul. A nem-gazda rezisztencia eseteben az akkumulacio korabban lebonyolodik. Ez oka lehet a HR hianyanak, amelyhez hozzajarulhat egy SOD gen es a BAX-inhibitor 1 gen atmeneti aktivalasa is. Ha hősokkal es antioxidansokkal a rezisztens novenyekben gatoljuk a O2.--kepződest, az ellenallo noveny reszlegesen fogekonnya valik. - Kideritettuk, hogy egy kemiai rezisztencia-induktor (DCINA) ugy fejti ki hatasat, hogy csokkenti az antioxidans kapacitast, igy fokozodik a H2O2 akkumulacioja, es ez ellenallosagot okoz az arpalisztharmat ellen. | Accumulation of ROS in infected plants may cause resistance to biotrophic pathogens, while high antioxidant capacity is responsible for symptom resistance during diseases caused by necrotrophs. - We created transgenic tobacco and potato that overexpress tomato superoxide dismutase and maize catalase genes. - We also increased the plant´s antioxidant capacity by applying low concentrations of H2O2 which 'immunizes' tobacco plants (induces symptom resistance to viral, bacterial and fungal infections). - It was possible to explain the hitherto unknown mechanism of non-host resistance by analyzing accumulation of O2.- in 18 host/pathogen combinations. In susceptible combinations there was no accumulation. In resistant hosts O2.- accumulated ca. 48 hours after infection. O2.- killed the pathogen and induced plant cell death (hypersensitive response, HR). During non-host resistance, accumulation of O2.- occurred rather early, killing the pathogen and inhibiting HR. Temporary activation of the genes SOD and BAX-inhibitor 1 may also contribute to the lack of HR. When we applied heath shock and antioxidant treatments to barley, accumulation of O2.- in infected non-host and host-resistant plants was suppressed and the resistant plants became partially susceptible to powdery mildew. - Analyzing the mechanism of action of a resistance inducer (DCINA), we detected lower antioxidant capacity in treated barley and a twofold accumulation of H2O2 which caused resistance to powdery mildew.