title: Fate of the biological control agent Pseudomonas aureofaciens TX-1 after application to turfgrass.
abstract: The fate and impact of Pseudomonas aureofaciens TX-1 following application as a biocontrol agent for fungi in turfgrass were studied. The organism was applied with a modified irrigation system by using a preparation containing 1 x 10(6) P. aureofaciens TX-1 CFU ml(-1) about 100 times between May and August. We examined the impact of this repeated introduction of P. aureofaciens TX-1 (which is known to produce the antimicrobial compound phenazine-1-carboxylic acid) on the indigenous microbial community of the turfgrass system and on establishment of introduced bacteria in the soil system. A PCR primer-DNA hybridization probe combination was developed to accurately monitor the fate of P. aureofaciens TX-1 following application in irrigation water. To assess the impact of frequent P. aureofaciens TX-1 applications on the indigenous bacterial community, turfgrass canopy, thatch, and rhizosphere samples were obtained during the growing season from control and treated plots and subjected to DNA extraction procedures and denaturing gradient gel electrophoresis (DGGE). PCR amplification and hybridization of extracted DNA with the P. aureofaciens TX-1-specific primer-probe combination revealed that P. aureofaciens TX-1 not only became established in the rhizosphere and thatch but also was capable of overwintering. Separation of PCR-amplified partial 16S rRNA genes by DGGE showed that the repeated application of P. aureofaciens TX-1 in irrigation water resulted in transient displacement of a leaf surface bacterial community member. There was no obvious alteration of any dominant members of the thatch and rhizosphere microbial communities.
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: W V
authors.initials: WV
authors.lastname: Sigler
authors.forename: C H
authors.initials: CH
authors.lastname: Nakatsu
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Reicher
authors.forename: R F
authors.initials: RF
authors.lastname: Turco
mesh_terms: D004275:DNA, Ribosomal / Q000032:analysis; D004587:Electrophoresis, Agar Gel / Q000379:methods; D008969:Molecular Sequence Data; D010572:Pest Control, Biological / Q000379:methods*; D010619:Phenazines / Q000378:metabolism; D006109:Poaceae / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004275:DNA, Ribosomal; D010619:Phenazines; D012336:RNA, Ribosomal, 16S; C037165:1-phenazinecarboxylic acid