The Sclerotinia sclerotiorum Slt2 mitogen-activated protein kinase ortholog, SMK3, is required for infection initiation but not lesion expansion.

Mitogen-activated protein kinases (MAPKs) play a central role in transferring signals and regulating gene expression in response to extracellular stimuli. An ortholog of the Saccharomyces cerevisiae cell wall integrity MAPK was identified in the phytopathogenic fungus Sclerotinia sclerotiorum. Disruption of the S.

Brassica napus polygalacturonase inhibitor proteins inhibit Sclerotinia sclerotiorum polygalacturonase enzymatic and necrotizing activities and delay symptoms in transgenic plants.

Sclerotinia sclerotiorum releases a battery of polygalacturonases (PGs) during infection, which the host plant may cope with through production of polygalacturonase inhibitor proteins (PGIPs). To study the interaction between S. sclerotiorum PGs and Brassica napus PGIPs, 5 S.

Arabidopsis mutant sk156 reveals complex regulation of SPL15 in a miR156-controlled gene network.

Background: The Arabidopsis microRNA156 (miR156) regulates 11 members of the SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) family by base pairing to complementary target mRNAs. Each SPL gene further regulates a set of other genes; thus, miR156 controls numerous genes through a complex gene regulation network. Increased axillary branching occurs in transgenic Arabidopsis overexpressing miR156b, similar to that observed in loss-of-function max3 and max4 mutants with lesions in carotenoid cleavage dioxygenases.

Arabidopsis cpSRP54 regulates carotenoid accumulation in Arabidopsis and Brassica napus.

An Arabidopsis thaliana mutant, cbd (carotenoid biosynthesis deficient), was recovered from a mutant population based on its yellow cotyledons, yellow-first true leaves, and stunted growth. Seven-day-old seedlings and mature seeds of this mutant had lower chlorophyll and total carotenoids than the wild type (WT). Genetic and molecular characterization revealed that cbd was a recessive mutant caused by a T-DNA insertion in the gene cpSRP54 encoding the 54 kDa subunit of the chloroplast signal recognition particle.

Factors governing the regulation of Sclerotinia sclerotiorum cutinase A and polygalacturonase 1 during different stages of infection.

Sclerotinia sclerotiorum releases hydrolytic enzymes that sequentially degrade the plant cuticle, middle lamellae, and primary and secondary cell walls. The cuticle was found to be a barrier to S. sclerotiorum infection, as leaves stripped of epicuticular wax were more rapidly colonized.

Enhanced seed carotenoid levels and branching in transgenic Brassica napus expressing the Arabidopsis miR156b gene.

The Arabidopsis AtmiR156b gene was expressed in Brassica napus under the control of the cauliflower mosaic virus (CaMV) 35S promoter and the seed-specific napin promoter. Seed carotenoid levels, branching habit, seed yield, and seed weight were examined in the transgenic B. napus.

Isolation of fungal homokaryotic lines from heterokaryotic transformants by sonic disruption of mycelia.

Fungal hyphae--and in some cases, spores--are multi-nucleate. During genetic transformation of these spores or mycelia, only one nucleus generally receives the transferred T-DNA generating heterokaryotic colonies. Characterization of genetic changes, such as the effects of gene disruption in the transformants, requires purified homokaryotic lines.

Identification and characterization of an alternative oxidase in the entomopathogenic fungus Metarhizium anisopliae.

Mitochondria of Metarhizium anisopliae contain an alternative oxidase (AOX), which reduces oxygen to water by accepting electrons directly from ubiquinol. AOX activity is demonstrated in situ as a constitutive enzyme. Greatest activity of AOX appears at the beginning and at the end of the fungal developmental cycle, germination of aerial conidia and the formation of submerged conidia, respectively.

Addition of exogenous carbon and nitrogen sources to aphid exuviae modulates synthesis of proteases and chitinase by germinating conidia of Beauveria bassiana.

Secretion of catabolic extracellular enzymes (ECE) is the hallmark of the infection of insects through the cuticle by entomopathogenic fungi (EPF). In this paper, we show that germinating conidia of Beauveria bassiana (Bb) regulate the synthesis of ECE through a multiple control mode during the initial stages of germination. We tested Bb conidial growth on aphid exuviae with or without supplementation of additional carbon and/or nitrogen (C/N) compounds.

Isolation and characterization of nucleotide excision repair deficient mutants of the entomopathogenic fungus, Beauveria bassiana.

To better understand DNA repair in the entomopathogenic fungus Beauveria bassiana, three ultraviolet (UV) light sensitive mutants were isolated and characterized to be deficient in nucleotide excision repair (NER). The UV sensitive mutants were scored by comparison to survival of the parental isolate, GK2016, after 36 J/m(2) UV-C irradiation. At this dose, conidial survival of GK2016 was 98% and the mutants LC75, LC194, and LC85 had survival values of 63%, 45%, and 31%, respectively.

Hydrated conidia of Metarhizium anisopliae release a family of metalloproteases.

Metarhizium anisopliae spores release isoforms of metalloprotease during hydration over a 4-day incubation period. The isoforms were identified and characterized by using one-dimensional native PAGE (1-DE nPAGE) and one-dimensional SDS non-dissociating (1-DE nSDS-PAGE) zymography. The ability of these isozymes to degrade gelatin varied as revealed by 2-D spot densitometry.

Biochemical and taxonomic characterization of bacteria associated with the crucifer root maggot (Delia radicum).

The crucifer root maggot, Delia radicum, is an important pest of cruciferous crops; however, little is known about its digestive biochemistry or resident gut microbiota. A culturing approach was used to survey the types of micro organisms associated with eggs, midgut, and faeces of larvae feeding on rutabaga. All bacteria isolated from the midgut and faecal materials were Gram-negative bacilli.

Quantification of ultraviolet-C irradiation induced cyclobutane pyrimidine dimers and their removal in Beauveria bassiana conidiospore DNA.

Ultraviolet (UV) radiation-induced DNA damage leading to entomopathogenic fungal inactivation is commonly measured by viability counts. Here we report the first quantification of UV-induced cyclobutane pyrimidine dimers (CPD) in DNA of the entomopathogenic fungus, Beauveria bassiana. Changes in the mobility of UV-C irradiated DNA were resolved with CPD specific bacteriophage T4 endonuclease V and alkaline agarose gel electrophoresis.

Restriction fragment length polymorphism of mitochondrial genome of the entomopathogenic fungus Beauveria bassiana reveals high intraspecific variation.

Beauveria bassiana is an entomopathogenic fungus with a growing potential for pest control in different agro-ecosystems worldwide. Such potential brings the necessity of developing a strain specific typing system. In a previous study, we reported the identification of molecular variants in mitochondrial DNA (mtDNA) polymorphism in 15 North American isolates.

Modeling the structure of the type I peritrophic matrix: characterization of a Mamestra configurata intestinal mucin and a novel peritrophin containing 19 chitin binding domains.

Twelve to fourteen integral proteins were found to reside in the Type I peritrophic matrix (PM) of Mamestra configurata (bertha armyworm) larvae. Several methods were employed, including de novo peptide sequencing, the generation of a midgut-specific EST database and immunological screening, which led to the isolation of cDNAs encoding two integral PM proteins. McPM1, the largest PM protein described to date at 202 kDa, was comprised of a concatamer of 19 chitin binding domains (CBD), 12 of which resided within a central repetitive region consisting of six iterations of a two CBD module.

Treatment of Salmonella enterica serovar Enteritidis with a sublethal concentration of trisodium phosphate or alkaline pH induces thermotolerance.

The responses of Salmonella enterica serovar Enteritidis to a sublethal dose of trisodium phosphate (TSP) and its equivalent alkaline pH made with NaOH were examined. Pretreatment of S. enterica serovar Enteritidis cells with 1.

Permeabilization of Beauveria bassiana blastospores for in situ enzymatic assays.

Vigorous agitation of an aqueous suspension of blastospores (BS) of Beauveria bassiana mixed with nine volumes of a 1:4 (v/v) mixture of toluene:ethanol (95%) for 10 min permits blastospore permeabilization. Agitation results in greater membrane permeabilization than heating blastospores in the presence of toluene:ethanol or the detergents Triton X-100, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide and Brij-35. The β-galactosidase activity in permeabilized blastospores was determined with these methods.

High pH during trisodium phosphate treatment causes membrane damage and destruction of Salmonella enterica serovar enteritidis.

Trisodium phosphate (TSP) is now widely used during the processing of poultry and red meats, but the mechanism whereby it inactivates gram-negative bacteria such Salmonella spp. remains unclear. Thus, Salmonella enterica serovar Enteritidis (ATCC 4931) cells were treated with different concentrations of TSP (1.

A Bacillus thuringiensis Isolate Found on Grapes Imported from California.

Samples of fruit and vegetable products were examined for presence of bacteria. A gram-positive, sporogenous, crystalliferous bacterium was isolated from Red Tokay grapes imported from California. This isolate was confirmed to be Bacillus thuringiensis var.