Host range of a deleterious rhizobacterium for biological control of downy brome

Abstract

Pseudomonas fluorescens strain D7 (P. f. D7; NRRL B-18293) is a root-colonizing bacterium that inhibits downy brome (Bromus tectorum L. BROTE) growth. Before commercialization as a biological control agent, strain D7 must be tested for host plant specificity. Agar plate bioassays in the laboratory and plant–soil bioassays in a growth chamber were used to determine the influence of P. f. D7 on germination and root growth of 42 selected weed, cultivated or native plant species common in the western and midwestern United States. In the agar plate bioassay, all accessions of downy brome were inhibited by P. f. D7. Root growth of seven Bromus spp. was inhibited an average of 87% compared with that of controls in the agar plate bioassay. Root growth of non-Bromus monocots was reduced by 0 to 86%, and only 6 out of 17 plant species were inhibited 40% or greater. Among all plant species, only downy brome root growth from two accessions was significantly inhibited by P. f. D7 in plant–soil bioassays (42 and 64%). P. f. D7 inhibited root growth and germination in agar plate bioassays more than in plant–soil bioassays. Inhibition in plant–soil bioassays was limited to downy brome, indicating promise for P. f. D7 as a biocontrol agent that will not harm nontarget species.

IAA Producing Enterobacter sp. I-3 as a Potent Bio-herbicide Candidate for Weed Control: A Special Reference with Lettuce Growth Inhibition

“…The number of DRBs belongs to the genus of Aeromonas, Agrobacterium, Alcaligenes, Bacillus, Burkholderia, Chryseomonas, Enterobacter, Microbacterium, Pseudomonas and Xanthomonas were reported by several studies [12][13][14]. On the other hand, the deleterious effect of bacterium on plants can be species or cultivars specific [15]. For this reason, we tested the bacterial isolate I-3 and I-4-5 on lettuce to confirm their deleterious effect.…”

5 Key Challenges and Solutions for Governing Complex Adaptive (Food) Systems

“…Research on alternative methods are in their infancy, but can produce practical results, e.g., microbial herbicides [174,175]. For example, organic agriculture suffers a yield gap compared to conventional agriculture, but use of Best Management Practices minimizes this gap [176].…”

Microbial Weed Control and Microbial Herbicides

“…After finding that only two plant species were inhibited, they concluded that A. alternata would not be harmful to any economically important plants. Kennedy et al (2001) found that Pseudomonas fluorescens strain D7 inhibited the target weed, downy brome, a few other Bromus species, jointed goatgrass and medusahead (Taeniatherum caput-medusae) in bioassays, greenhouse and field studies. They investigated representatives from a wide array of families that included native, crop and weed species, while concentrating on familes, tribes, subtribes and accessions closely related to Bromus species.…”