Nematicidal Bacteria Associated to Pinewood Nematode Produce Extracellular Proteases
نویسندگان
چکیده
Bacteria associated with the nematode Bursaphelenchus xylophilus, a pathogen of trees and the causal agent of pine wilt disease (PWD) may play a role in the disease. In order to evaluate their role (positive or negative to the tree), strains isolated from the track of nematodes from infected Pinus pinaster trees were screened, in vitro, for their nematicidal potential. The bacterial products, from strains more active in killing nematodes, were screened in order to identify and characterize the nematicidal agent. Forty-seven strains were tested and, of these, 21 strains showed capacity to produce extracellular products with nematicidal activity. All Burkholderia strains were non-toxic. In contrast, all Serratia strains except one exhibited high toxicity. Nematodes incubated with Serratia strains showed, by SEM observation, deposits of bacteria on the nematode cuticle. The most nematicidal strain, Serratia sp. A88copa13, produced proteases in the supernatant. The use of selective inhibitors revealed that a serine protease with 70 kDa was majorly responsible for the toxicity of the supernatant. This extracellular serine protease is different phylogenetically, in size and biochemically from previously described proteases. Nematicidal assays revealed differences in nematicidal activity of the proteases to different species of Bursaphelenchus, suggesting its usefulness in a primary screen of the nematodes. This study offers the basis for further investigation of PWD and brings new insights on the role bacteria play in the defense of pine trees against B. xylophilus. Understanding all the factors involved is important in order to develop strategies to control B. xylophilus dispersion.
منابع مشابه
Proteases from Bacillus: a new insight into the mechanism of action for rhizobacterial suppression of nematode populations.
AIMS The aim of this study was to investigate the role of proteases in Bacillus spp. of rhizobacteria in suppressing nematode populations and to understand their mechanism of action. METHODS AND RESULTS Rhizobacteria with nematicidal activity were isolated from soil samples of five root knot nematode-infested farms. Among these strains, nematotoxicities of Bacillus strains were intensively an...
متن کاملNematicidal Activity of Plant Essential Oils and Components From Ajowan (Trachyspermum ammi), Allspice (Pimenta dioica) and Litsea (Litsea cubeba) Essential Oils Against Pine Wood Nematode (Bursaphelenchus Xylophilus).
Commercial plant essential oils from 26 plant species were tested for their nematicidal activities against the pinewood nematode, Bursaphelenchus xylophilus. Good nematicidal activity against B. xylophilus was achieved with essential oils of ajowan (Trachyspermum ammi), allspice (Pimenta dioica) and litsea (Litsea cubeba). Analysis by gas chromatography-mass spectrometry led to identification o...
متن کاملNematicidal activity of essential oils and volatiles derived from Portuguese aromatic flora against the pinewood nematode, Bursaphelenchus xylophilus.
Twenty seven essential oils, isolated from plants representing 11 families of Portuguese flora, were screened for their nematicidal activity against the pinewood nematode (PWN), Bursaphelenchus xylophilus. The essential oils were isolated by hydrodistillation and the volatiles by distillation-extraction, and both were analysed by GC and GC-MS. High nematicidal activity was achieved with essenti...
متن کاملA Soluble Acetylcholinesterase Provides Chemical Defense against Xenobiotics in the Pinewood Nematode
The pinewood nematode genome encodes at least three distinct acetylcholinesterases (AChEs). To understand physiological roles of the three pinewood nematode AChEs (BxACE-1, BxACE-2, and BxACE-3), BxACE-3 in particular, their tissue distribution and inhibition profiles were investigated. Immunohistochemistry revealed that BxACE-1 and BxACE-2 were distributed in neuronal tissues. In contrast, BxA...
متن کاملBiological Control of African Violets Root-Knot Disease by the Used of Extracellular Protease Bacillus
The present study explored the efficacy of Bacillus spp. and protease production for biocontrol of the root-knot nematode Meloidogyne javanica in African violet media. Among 100 bacterial isolates from various soils, the highest nematode mortality was observed for treatments with isolate GM-18, which was identified as Bacillus subtilis based on cultural and morphological characteristics and 16S...
متن کامل