First evidence for improved resistance to fire blight in transgenic pear expressing the attacin E gene from Hyalophora cecropia

摘要

Fire blight, caused by Erwinia amylovora, is the most important bacterial disease of pear (Pyrus communis L.). Attacin E, a lytic protein originating from Hyalophora cecropia, has been previously reported to be active against E. amylovora in transgenic apple. integration of the attacin E gene under control of a derivative of the constitutive promoter CaMV35S was accomplished using a transformation protocol developed for several pear cultivars. The integration was checked by polymerase chain reaction (PCR) for 11 lines of the cultivar Passe Crassane. Expression was determined in in vitro plantlets. The differences in transcription levels among lines revealed by comparative reverse transcription PCR correlated very well with the differences in attacin E accumulation observed by Western blot analysis. Fire blight inoculations were performed in vitro on all transgenic lines. A significant reduction of symptoms was observed for six lines, in comparison with the susceptible control Passe Crassane.