ABSTRACT
BACKGROUND: Pine wilt disease, caused by the pinewood nematode Bursaphelenchus xylophilus (PWN), is an important destructive disease of pine forests worldwide. In addition to behaving as a plant-parasitic nematode that feeds on epithelial cells of pines, this pest relies on fungal associates for completing its life cycle inside pine trees. Manipulating microbial symbionts to block pest transmission has exhibited an exciting prospect in recent years; however, transforming the fungal mutualists to toxin delivery agents for suppressing PWN growth has received little attention. RESULTS: In the present study, a nematicidal gene cry5Ba3, originally from a soil Bacillus thuringiensis (Bt) strain, was codon-preferred as cry5Ba3Φ and integrated into the genome of a fungus eaten by PWN, Botrytis cinerea, using Agrobacterium tumefaciens-mediated transformation. Supplementing wild-type B. cinerea extract with that from the cry5Ba3Φ transformant significantly suppressed PWN growth; moreover, the nematodes lost fitness significantly when feeding on the mycelia of the cry5Ba3Φ transformant. N-terminal deletion of Cry5Ba3Φ protein weakened the nematicidal activity more dramatically than did the C-terminal deletion, indicating that domain I (endotoxin-N) plays a more important role in its nematicidal function than domain III (endotoxin-C), which is similar to certain insecticidal Cry proteins. CONCLUSIONS: Transformation of Bt nematicidal cry genes in fungi can alter the fungivorous performance of B. xylophilus and reduce nematode fitness. This finding provides a new prospect of developing strategies for breaking the life cycle of this pest in pines and controlling pine wilt disease.
Subject(s)
Bacillus thuringiensis/metabolism , Bacterial Proteins/metabolism , Botrytis/metabolism , Nematoda/metabolism , Nematoda/microbiology , Animals , Bacillus thuringiensis/genetics , Bacterial Proteins/genetics , Botrytis/genetics , Nematoda/genetics , Pinus/parasitologyABSTRACT
Copper-based metal organic framework (Cu-BTC) was prepared and used to remove dibutyl phthalate (DBP) in the presence of persulfate (PS). The surface characteristics, textural properties, and stability of activated Cu-BTC (denoted as Cu-BTC-A) were evaluated by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N2 physical adsorption-desorption, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The effects of parameters such as initial pH, PS concentration, catalyst dosage, and free-radical quenchers have been investigated. The results showed that DBP could be removed in a wide pH range by Cu-BTC-A via mechanisms of adsorption and heterogeneous catalytic reaction. Unfortunately, the DBP removal was not completed because of radical scavenging reactions in Cu-BTC-A cages where PS can enter freely but DBP is blocked outside. Another explanation was that Cu-BTC-A showed a low adsorption capacity for DBP because the molecular size of DBP (15.84 × 11.00 × 7.56 Å) is larger than microporous cages (approximately 9 × 9 Å in diameter) of Cu-BTC-A.
ABSTRACT
Paenibacillus polymyxa CF05 is a Gram-positive rod-shaped bacterium isolated from the interior of an ancient tree, Cryptomeria fortunei, in China. This bacterium displays potent biocontrol effects against certain soil-borne diseases and the elicitation of induced systemic resistance in tomatoes. Here, we report the complete genome sequence of P. polymyxa CF05.