scholarly journals α-l-Fucosidases from Bursaphelenchus xylophilus Secretome—Molecular Characterization and Their Possible Role in Breaking Down Plant Cell Walls

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 265
Author(s):  
Joana M.S. Cardoso ◽  
Luís Fonseca ◽  
Isabel Abrantes

The pinewood nematode (PWN) Bursaphelenchus xylophilus, the causal agent of the pine wilt disease (PWD), enters above-ground parts of the tree, migrates through the resin canals and feeds on plant cells causing extensive damage. In order to penetrate the cell wall and establish a parasitic relationship with host trees, the PWN needs to secretea mixture of active cell wall degrading enzymes. In maritime pine, Pinus pinaster, which is high susceptible to PWN, xyloglucan is the major hemicellulosic polysaccharide in primary cells. The xyloglucan backbone is susceptible to hydrolysis by numerous endoglucanases, some of them specific to xyloglucan. However, to completely degrade xyloglucan, all substitutions on the glucan backbones must be released, and l-fucose residues in xyloglucan branches are released by α-l-fucosidases. In the present study, the molecular characterization of two α-l-fucosidases found in PWN secretome was performed. Moreover, a novel α-l-fucosidase was identified and its cDNA and gene sequence were determined. The three-dimensional structures of these α-l-fucosidases were predicted and the transcript levels were analyzed, thus providing new insights into fundamental PWN biology and the possible role of these proteins as cell wall degrading enzymes.

2021 ◽  
Vol 12 ◽  
Author(s):  
Inês Modesto ◽  
Lieven Sterck ◽  
Vicent Arbona ◽  
Aurelio Gómez-Cadenas ◽  
Isabel Carrasquinho ◽  
...  

Pine wilt disease (PWD), caused by the plant–parasitic nematode Bursaphelenchus xylophilus, has become a severe environmental problem in the Iberian Peninsula with devastating effects in Pinus pinaster forests. Despite the high levels of this species' susceptibility, previous studies reported heritable resistance in P. pinaster trees. Understanding the basis of this resistance can be of extreme relevance for future programs aiming at reducing the disease impact on P. pinaster forests. In this study, we highlighted the mechanisms possibly involved in P. pinaster resistance to PWD, by comparing the transcriptional changes between resistant and susceptible plants after infection. Our analysis revealed a higher number of differentially expressed genes (DEGs) in resistant plants (1,916) when compared with susceptible plants (1,226). Resistance to PWN is mediated by the induction of the jasmonic acid (JA) defense pathway, secondary metabolism pathways, lignin synthesis, oxidative stress response genes, and resistance genes. Quantification of the acetyl bromide-soluble lignin confirmed a significant increase of cell wall lignification of stem tissues around the inoculation zone in resistant plants. In addition to less lignified cell walls, susceptibility to the pine wood nematode seems associated with the activation of the salicylic acid (SA) defense pathway at 72 hpi, as revealed by the higher SA levels in the tissues of susceptible plants. Cell wall reinforcement and hormone signaling mechanisms seem therefore essential for a resistance response.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Nunes da Silva ◽  
Carla S. Santos ◽  
Ana Cruz ◽  
Adrián López-Villamor ◽  
Marta W. Vasconcelos

AbstractThe pine wilt disease (PWD), for which no effective treatment is available at the moment, is a constant threat to Pinus spp. plantations worldwide, being responsible for significant economic and environmental losses every year. It has been demonstrated that elicitation with chitosan increases plant tolerance to the pinewood nematode (PWN) Bursaphelenchus xylophilus, the causal agent of the PWD, but the biochemical and genetic aspects underlying this response have not been explored. To understand the influence of chitosan in Pinus pinaster tolerance against PWN, a low-molecular-weight (327 kDa) chitosan was applied to mock- and PWN-inoculated plants. Nematode population, malondialdehyde (MDA), catalase, carotenoids, anthocyanins, phenolic compounds, lignin and gene expression related to oxidative stress (thioredoxin 1, TRX) and plant defence (defensin, DEF, and a-farnesene synthase, AFS), were analysed at 1, 7, 14, 21 and 28 days post-inoculation (dpi). At 28 dpi, PWN-infected plants elicited with chitosan showed a sixfold lower nematode population when compared to non-elicited plants. Higher levels of MDA, catalase, carotenoids, anthocyanins, phenolic compounds, and lignin were detected in chitosan-elicited plants following infection. The expression levels of DEF gene were higher in elicited plants, while TRX and AFS expression was lower, possibly due to the disease containment-effect of chitosan. Combined, we conclude that chitosan induces pine defences against PWD via modulation of metabolic and transcriptomic mechanisms related with plant antioxidant system.


2020 ◽  
Vol 3 (1) ◽  
pp. 31
Author(s):  
Jorge M. S. Faria ◽  
Ana Margarida Rodrigues ◽  
Pedro Barbosa ◽  
Manuel Mota

Chemical control has been the most effective and reliable containment strategy in integrated pest management of pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Yet, large spectrum nematicides can be dangerous to human health and the environment. Essential oils (EOs) are safer sustainable alternatives, being composed of highly active natural compounds. A survey of bibliographic data on the detailed chemical composition and activity of the EOs used against the PWN allowed pinpointing monoterpenes as the main source of structures with agonist or antagonist properties. Transversal EO data treatment can identify potential highly active anti-PWN compounds.


2011 ◽  
Vol 9 (2) ◽  
pp. 272-275 ◽  
Author(s):  
Albina R. Franco ◽  
Carla Santos ◽  
Mariana Roriz ◽  
Rui Rodrigues ◽  
Marta R. M. Lima ◽  
...  

Pine wilt disease, caused by the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, is originating severe infections in pine trees. The disease is detected when external symptoms appear (e.g. needle chlorosis), but trees could remain asymptomatic for long periods and serve as a long-term host. The primary goal of this study was to assess the effect of inoculation with an avirulent isolate of B. xylophilus (C14-5) on different Pinus spp. seedlings (P. sylvestris, P. nigra, P. pinea and P. pinaster). At the same time, seedlings were also inoculated with a virulent strain, HF, in order to compare the phenotypic and genomic results of the two types of inoculations. The effect of inoculation was determined in terms of expression of various Pinus genes potentially involved in the response to the disease.The results suggest that P. pinea and P. nigra are more resistant to infection by the nematode than P. sylvestris and P. pinaster. The phenotypic and genetic differences were more marked among P. pinea and P. pinaster.


2019 ◽  
Vol 377 ◽  
pp. 120325 ◽  
Author(s):  
Antonio Zuorro ◽  
Veronica Malavasi ◽  
Giacomo Cao ◽  
Roberto Lavecchia

Sign in / Sign up

Export Citation Format

Share Document