Plant-Scale Validation of Physical Heat Treatment of Poultry Litter Composts Using Surrogate and Indicator Microorganisms for .

This study selected and used indicator and surrogate microorganisms for to validate the processes for physically heat-treated poultry litter compost in litter processing plants. Initially laboratory validation studies indicated that 1.2- to 2.

Microbiome Networks: A Systems Framework for Identifying Candidate Microbial Assemblages for Disease Management.

Network models of soil and plant microbiomes provide new opportunities for enhancing disease management, but also challenges for interpretation. We present a framework for interpreting microbiome networks, illustrating how observed network structures can be used to generate testable hypotheses about candidate microbes affecting plant health. The framework includes four types of network analyses.

Assessment of DAPG-producing Pseudomonas fluorescens for Management of Meloidogyne incognita and Fusarium oxysporum on Watermelon.

Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R, and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogyne incognita (root-knot nematode: RKN) and Fusarium oxysporum f. sp.

Both extracellular chitinase and a new cyclic lipopeptide, chromobactomycin, contribute to the biocontrol activity of Chromobacterium sp. C61.

Chromobacterium sp. strain C61 displays antifungal activities in vitro and has been used successfully for the biocontrol of plant diseases under field conditions. In this study, the roles of extracellular chitinase and an antifungal compound produced by strain C61 were investigated to elucidate their contributions to biological control activity.

Sampling and Selection Factors that Enhance the Diversity of Microbial Collections: Application to Biopesticide Development.

Diverse bacteria are known to colonize plants. However, only a small fraction of that diversity has been evaluated for their biopesticide potential. To date, the criteria for sampling and selection in such bioprospecting endeavors have not been systematically evaluated in terms of the relative amount of diversity they provide for analysis.

Distribution of SUN, OVATE, LC, and FAS in the tomato germplasm and the relationship to fruit shape diversity.

Phenotypic diversity within cultivated tomato (Solanum lycopersicum) is particularly evident for fruit shape and size. Four genes that control tomato fruit shape have been cloned. SUN and OVATE control elongated shape whereas FASCIATED (FAS) and LOCULE NUMBER (LC) control fruit locule number and flat shape.

Linking sequence to function in soil bacteria: sequence-directed isolation of novel bacteria contributing to soilborne plant disease suppression.

Microbial community profiling of samples differing in a specific ecological function, i.e., soilborne plant disease suppression, can be used to mark, recover, and ultimately identify the bacteria responsible for that specific function.

Farm Management Effects on Rhizosphere Colonization by Native Populations of 2,4-Diacetylphloroglucinol-Producing Pseudomonas spp. and Their Contributions to Crop Health.

ABSTRACT Analyses of multiple field experiments indicated that the incidence and relative abundance of root-colonizing phlD+ Pseudomonas spp. were influenced by crop rotation, tillage, organic amendments, and chemical seed treatments in subtle but reproducible ways. In no-till corn plots, 2-year rotations with soybean resulted in plants with approximately twofold fewer phlD+ pseudomonads per gram of root, but 3-year rotations with oat and hay led to population increases of the same magnitude.

Diversity of Ralstonia solanacearum Infecting Eggplant in the Philippines.

ABSTRACT The diversity of Ralstonia solanacearum strains isolated from eggplant (Solanum melongena) grown in five provinces of the Philippine island group of Luzon was assessed using a recently described hierarchical system. All strains keyed to race 1, biovar 3 or 4. Phylotype-specific multiplex polymerase chain reaction (PCR) indicated that, like most other strains of Asian origin, all the strains in our Philippine collection belong to phylotype I.

Field management effects on damping-off and early season vigor of crops in a transitional organic cropping system.

Transitioning farmland to certified organic vegetable production can take many paths, each varying in their costs and benefits. Here, the effects of four organic transition strategies (i.e.

2,4-diacetylphloroglucinol alters plant root development.

Pseudomonas fluorescens isolates containing the phlD gene can protect crops from root pathogens, at least in part through production of the antibiotic 2,4-diacetylphloroglucinol (DAPG). However, the action mechanisms of DAPG are not fully understood, and effects of this antibiotic on host root systems have not been characterized in detail. DAPG inhibited primary root growth and stimulated lateral root production in tomato seedlings.

Distribution and Fungicide Sensitivity of Fungal Pathogens Causing Anthracnose-like Lesions on Tomatoes Grown in Ohio.

The primary causal agents of anthracnose-like fruit rots in Ohio and their potential resistance to fungicides commonly used to control these fungal pathogens were determined. Nineteen tomato production fields throughout the state were sampled in 2002 and 2003 for fruit with anthracnose-like lesions. Fungi were isolated from these samples, classified using restriction fragment length polymorphism analysis, and identified by internal transcribed spacer sequence analysis.

Development of a real-time PCR-based system targeting the 16S rRNA gene sequence for rapid detection of Alicyclobacillus spp. in juice products.

The thermophilic, aciduric Alicyclobacillus spp. are becoming an increasing spoilage concern in the beverage industry. Rapid methods to detect their presence in both raw materials and final products are desirable for industrial quality control.

Minimal changes in rhizobacterial population structure following root colonization by wild type and transgenic biocontrol strains.

Pseudomonas fluorescens strains 2-79, Q8r1-96, and a recombinant strain, Z30-97, produce the antibiotics phenazine-1-carboxylic acid (PCA), 2,4-diacetylphloroglucinol (DAPG), or both antibiotics, respectively. Rhizosphere colonization by these strains and subsequent alterations of bacterial community structure were assayed over multiple growth cycles of wheat under controlled conditions. While added to soil at just log 4 cells per gram prior to planting, all four strains subsequently colonized germinating wheat roots to levels in excess of log 6.

Microbial populations responsible for specific soil suppressiveness to plant pathogens.

Agricultural soils suppressive to soilborne plant pathogens occur worldwide, and for several of these soils the biological basis of suppressiveness has been described. Two classical types of suppressiveness are known. General suppression owes its activity to the total microbial biomass in soil and is not transferable between soils.

Detection and isolation of novel rhizopine-catabolizing bacteria from the environment.

Microbial rhizopine-catabolizing (Moc) activity was detected in serial dilutions of soil and rhizosphere washes. The activity observed generally ranged between 10(6) and 10(7) catabolic units per g, and the numbers of nonspecific culture-forming units were found to be approximately 10 times higher. A diverse set of 37 isolates was obtained by enrichment on scyllo-inosamine-containing media.

Isolation, characterization, and transfer of cryptic gene-mobilizing plasmids in the wheat rhizosphere.

A set of self-transmissible plasmids with IncQ plasmid-mobilizing capacity was isolated by triparental exogenous isolation from the wheat rhizosphere with an Escherichia coli IncQ plasmid host and a Ralstonia eutropha recipient. Three plasmids of 38 to 45 kb, denoted pIPO1, pIPO2, and pIPO3, were selected for further study. No selectable traits (antibiotic or heavy-metal resistance) were identified in these plasmids.