Plant growth-promoting bacteria that confer resistance to water stress in tomatoes and peppers

The work reported here evaluates whether bacteria populating arid and salty environments can confer resistance in tomato and pepper plants to water stress. Plant growth-promoting bacteria that have ACC deaminase activity were isolated from soil samples taken from the Arava region of southern Israel. One of these strains, Achromobacter piechaudii ARV8 [Mayak et al., Plant growth-promoting bacteria that confer resistance in tomato and pepper plants to salt stress, submitted for publication.] significantly increased the fresh and dry weights of both tomato and pepper seedlings exposed to transient water stress. In addition, the bacterium reduced the production of ethylene by tomato seedlings, following water stress. During water deprivation the bacterium did not influence the reduction in relative water content; however, it significantly improved the recovery of plants when watering was resumed. Inoculation of tomato plants with the bacterium resulted in continued plant growth during both the water stress and after watering was resumed. Based on the results of the experiments reported herein, the use of plant growth-promoting bacteria such as A. piechaudii AM may provide a means of facilitating plant growth in arid environments. (C) 2003 Elsevier Ireland Ltd. All rights reserved.