Rob Zdor (Biology)
Exploring Possible Synergy in Weed Suppression with Multiple Strains of Deleterious Rhizobacteria
The ability of weed deleterious rhizobacteria to reduce plant growth is dependent on the production of bacterial factors such as cyanide and plant hormones. Bacteria use glycine to produce the toxic metabolite cyanide and previous work has documented that the presence of glycine in soil correlates with increased plant growth suppression by cyanogenic bacteria (Owen and Zdor 2001). Work by Brubaker and Zdor (2008) documented that velvetleaf plants irrigated with tryptophan-containing water and colonized by bacteria that produce IAA-like substances experienced less growth than plants cultivated in inoculated soil lacking tryptophan. Work with lettuce has shown the presence of tryptophan to promote root inhibition by rhizobacteria (Barazani and Friedman 2000). This data suggests that rhizosphere conditions can be manipulated to favor the action of rhizobacteria in suppressing weeds. This work will test for the effect of combined strains on velvetleaf growth. Prior work has shown that coinoculation of bean plants with 2 pseudomonad bacterial strains was compatible with the production of cyanide in the rhizosphere suggesting that multiple bacterial strains can coexist in the rhizosphere (Jamali et al. 2009). It is this phenomenon that I want to test with my specific bacterial strains of interest.