Survival of Lum10-1 in sterile and non-sterile soil. The bacterial number was expressed as CFU g-1 dry weight of soils. Data are the average of three experiments and were analyzed using Student's t-test (P ≤ 0.05). Letter 'a' indicates the highest value, and 'g' the lowest value. The same letters within a column mean no significant differences exist between the numbers.