Publications by authors named "Gary Y Yuen"

Background: The biocontrol potential of soil microbes can reduce the extensive use of hazardous synthetic fungicides. This study was designed to find a strain of rhizobacteria indigenous to Pakistan with potential biocontrol against early blight of tomato caused by Alternaria solani and to characterize its biocontrol mechanisms.

Results: Among 88 strains tested for antagonism against A.

View Article and Find Full Text PDF

The Sandhills of Nebraska is a complex ecosystem, covering 50,000 km2 in central and western Nebraska and predominantly of virgin grassland. Grasslands are the most widespread vegetation in the U.S.

View Article and Find Full Text PDF

Bacilli are commonly used as plant growth-promoting agents but can be limited in effectiveness to certain crop and soil environments. The objectives of this study were to (1) identify strains that can be consistent in promoting the growth of corn, wheat, and soybean and (2) determine whether physiological traits expressed can be predictive of growth promotion efficacy/consistency and be used for selecting effective strains. Twelve strains isolated from wheat rhizospheres were evaluated in greenhouse pot tests with nonsterile soil for their effects on the growth of corn, soybean, and wheat.

View Article and Find Full Text PDF

K20 is a novel amphiphilic aminoglycoside capable of inhibiting many fungal species. K20's capabilities to inhibit Fusarium graminearum the causal agent wheat Fusarium head blight (FHB) and to this disease were examined. K20 inhibited the growth of F.

View Article and Find Full Text PDF

Ax21 family proteins have been shown to play regulatory roles in plant- and animal-pathogenic species in the bacterial family Xanthomonadaceae, but the protein have not been investigated previously in the non-pathogenic members of this bacterial family. Lysobacter enzymogenes, is a non-pathogenic species known for its capacity as a biocontrol agent of plant pathogens. It is also noted for the production of antimicrobial secondary metabolites, heat stable antifungal factor (HSAF) and WAP-8294A2, that have potential for agricultural and pharmaceutical applications.

View Article and Find Full Text PDF

Lysobacter enzymogenes strain C3 is a gliding bacterium which produces the antifungal secondary metabolite heat-stable antifungal factor (HSAF) and type IV pilus (T4P) as important mechanisms in biological control activity against fungal pathogens. To date, the regulators that control HSAF biosynthesis and T4P-dependent twitching motility in L. enzymogenes are poorly explored.

View Article and Find Full Text PDF

Switchgrass (Panicum virgatum) cultivars are currently under development as lignocellulosic feedstock. Here we present a survey of three established switchgrass experimental nurseries in Nebraska in which we identified Panicum mosaic virus (PMV) as the most prevalent virus. In 2012, 72% of 139 symptomatic plants tested positive for PMV.

View Article and Find Full Text PDF

Dihydromaltophilin (heat-stable antifungal factor [HSAF]) is an antifungal metabolite produced in Lysobacter enzymogenes biocontrol strain C3. This compound induces cell wall thickening in Aspergillus nidulans. Here we show that the cell wall thickening is a general response to HSAF in diverse fungal species.

View Article and Find Full Text PDF

ABSTRACT Induced resistance was found to be a mechanism for biological control of leaf spot, caused by Bipolaris sorokiniana, in tall fescue (Festuca arundinacea) using the bacterium Lysobacter enzymogenes strain C3. Resistance elicited by C3 suppressed germination of B. sorokiniana conidia on the phylloplane in addition to reducing the severity of leaf spot.

View Article and Find Full Text PDF
Article Synopsis
  • Lysobacter enzymogenes produces enzymes that break down fungal cell walls, contributing to its ability to control fungal diseases.* -
  • Strain C3 produces three beta-1,3-glucanases (gluA, gluB, gluC), which are highly similar to enzymes from another strain and are essential for breaking down laminarin, a carbon source.* -
  • Mutations in these glucanase genes reduced strain G123's growth on laminarin and decreased its effectiveness in controlling diseases like Bipolaris leaf spot and Pythium damping-off.*
View Article and Find Full Text PDF

Many mycotoxigenic fungi infect plant hosts and cause disease in the field. Therefore, control of field infection by these fungi is a critical step in managing mycotoxin accumulation in the harvested product. Fusarium graminearum, also known as Gibberella zeae, is the causal agent of Fusarium head blight (FHB), or scab, in cereals and is also the primary agent responsible for contamination of grain with deoxynivalenol (DON).

View Article and Find Full Text PDF

A global regulator was previously identified in Lysobacter enzymogenes C3, which when mutated, resulted in strains that were greatly reduced in the expression of traits associated with fungal antagonism and devoid of biocontrol activity towards bipolaris leaf-spot of tall fescue and pythium damping-off of sugarbeet. A clp gene homologue belonging to the crp gene family was found to globally regulate enzyme production, antimicrobial activity, and biological control activity expressed by Lysobacter enzymogenes C3 (Kobayashi et al. 2005).

View Article and Find Full Text PDF

Lysobacter enzymogenes strain C3, a biological control agent for plant diseases, produces multiple extracellular hydrolytic enzymes and displays antimicrobial activity against various fungal and oomycetous species. However, little is known about the regulation of these enzymes or their roles in antimicrobial activity and biocontrol. A study was undertaken to identify mutants of strain C3 affected in extracellular enzyme production and to evaluate their biocontrol efficacy.

View Article and Find Full Text PDF