Characterization of Bacteria Associated with Pinewood Nematode Bursaphelenchus xylophilus

Pedro Barbosa,Margarida Espada,Francisco Nascimento,Claudia S L Vicente,Manuel Mota,Bernard R Glick,Dawn Arnold,Solange Oliveira

doi:10.1371/journal.pone.0046661

Pedro Barbosa, Margarida Espada + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0046661

Copy DOI

Journal: PLoS ONE	Publication Date: Oct 16, 2012
Citations: 87	License type: CC BY 4.0

Affiliation: University of Évora, University of Waterloo

Abstract

Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD.

Highlights

Pine wilt disease (PWD) is a worldwide threat to forests, which has severely affected both Asian (Japan, China, Taiwan and South Korea) and European (Portugal and Spain) countries causing huge and irreversible economic and environmental damage [1,2]
The results indicate the presence of a diverse microbial community associated with B. xylophilus including some strains with traits that may be related to PWD symptoms and B. xylophilus pathogenicity
The work reported here was undertaken in an effort to gain some insight into the role of Bursaphelenchus xylophilus associated bacteria in PWD

Summary

Introduction

Pine wilt disease (PWD) is a worldwide threat to forests, which has severely affected both Asian (Japan, China, Taiwan and South Korea) and European (Portugal and Spain) countries causing huge and irreversible economic and environmental damage [1,2]. The pathogenic agent of PWD, Bursaphelenchus xylophilus, known as the pinewood nematode (PWN), is a migratory plant parasitic nematode that infects different species of pine trees (Pinus spp.), causing mainly blockage of the host vascular vessels and cavitation, thereby leading to development of wilting symptoms [3]. In the Asian forestlands affected by PWD, the genus Bacillus in Japan [12]; the genus Pseudomonas in China [8]; and the genera Brevibacterium, Burkholderia, Enterobacte,r Ewingella, and Serratia in Korea, were the most representative bacteria associated with the PWN [13]. The pathogenicity of these bacteria in Pinus pinaster seedlings was assessed

Methods

Results

Conclusion