Seeds were surface sterilized
by soaking themin ethanol for 1 min, rinsed shortly in 0.1% of
HgCl2 and then thoroughly washed then with distilled water according
to the method described by El-Abyad et al. (1993). Sterile seeds were incubated
for 2 h in 40 ml of bacterial suspension and gently stirred in the
dark at room temperature, after which they were removed from the
suspension using sterile pliers and sown. Seed sterility was verified by
incubating 10 seeds on LB agar at 30 °C for 10 days without any contamination
appearing.