Abstract
The 5'-upstream region of the pea phenylalanine ammonia-lyase gene2 (PSPAL2-FL, -2196 to +110) promoter was dissected by deleting in a series and fused to the coding region of the reporter gene encoding β-glucuronidase (GUS). The constructed chimeric promoters designated as PSPAL2-FLd1 (-1486 to +110), PSPAL2-FLd2 (-966 to +110), PSPAL2-FLd3 (-594 to +110) and the full-length promoter PSPAL2-FL (-2196 to +110) were used to transform tobacco plants by the Agrobacterium-mediated leaf disk method. Histochemically, GUS expression of the PSPAL2 promoter was examined in mature leaves of these transgenic tobacco leaves inoculated with pathogenic and non pathogenic fungi. GUS expression was induced by inoculation with a non pathogen, Phytophthora capsici, as detected by a very clear expression zone around the hypersensitive response (HR) area, especially in the transformants of PSPAL2-FL and PSPAL2-FLd1. However, on leaves inoculated with a pathogen, P. nicotianae, only weak and hazy colorations were detected around the inoculation site even in the transformant of PSPAL2-FL. Moreover, wounding mature leaves with a sterile razor blade also triggered remarkable expression around the wounded sites, especially in the transformant of PSPAL2-FL. We suggest that PSPAL2 promoter expression in transgenic tobacco is induced not only by fungal ingression but also by wounding.
