Amelioration of flooding stress by ACC deaminase-containing plant growth-promoting bacteria

Seeds of wild-type tomato plants Lycopersicon esculentum (Solanaceae) cv. H einz 902 were inoculated either with Enterobacter cloacae UW4, E. cloacae C AL2, Pseudomonas putida ATCC17399/pRKACC or P. purida ATCC17399/pRK415, the first three of these bacterial strains carrying and expressing the gene fo r 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase. When they were 55 d old, tomato plants were flooded for nine consecutive days before a number of physiological and biochemical parameters were assessed. Characteristics that were observed include root and shoot growth, epinastic curvature in l eaf petioles, ACC deaminase activity, ethylene production, and leaf chlorop hyll concentration. Tomato plants that were grown from seeds bacterized wit h organisms expressing ACC deaminase showed a substantial tolerance to floo ding stress. (C) 2001 Editions scientifiques et medicales Elsevier SAS.