Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- A biofertilizer with diazotrophic bacteria and a filamentous fungus increases Pinus pinaster tolerance to the pinewood nematode (Bursaphelenchus xylophilus)Publication . Silva, M. Nunes da; Pintado, M. E.; Sarmento, B.; Stamford, N. P.; Vasconcelos, M. W.The pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, is a devastating illness that mainly affects P. pinaster trees, and that poses great environmental and economic challenges. Current disease management involves the cut down of infected trees, tree fumigation, use of nematicides, or the control of the insect vector; however, these methodologies are expensive, labour-intensive and have limited success. The aim of this work was to evaluate the effect of a biofertilizer enriched with diazotrophic bacteria and a chitosan-producing fungus, Cunninghamella elegans, in inducing P. pinaster and P. pinea resistance against the PWN. In non-inoculated (control) P. pinaster plants, PWN population significantly increased (ca. 2.3-fold) throughout the experimental period, whereas in plants treated with 7.5 and 15% of biofertilizer nematode numbers were up to 36.3-fold lower than in control plants. In P. pinea, nematode numbers decreased with time for all biofertilizer concentrations tested, and P. pinea had up to 27.3-fold lower nematode counts than P. pinaster. In addition, the biofertilizer prevented the decrease of photosynthetic pigments and the reduction of water content in infected P. pinaster plants. In P. pinea the biosynthesis of phenolics increased in PWN-inoculated plants, especially in the presence of the biofertilizer. The addition of this biofertilizer to soils forested by P. pinaster may improve plant defence and could be a potentially simple and inexpensive strategy for the control of the PWD.
- Susceptibility evaluation of Picea abies and Cupressus lusitanica to the pinewood nematode, Bursaphelenchus xylophilusPublication . Silva, M. Nunes da; Lima, M. R. M.; Vasconcelos, Marta W.Pine wilt disease (PWD), recently introduced into Europe, is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus and is a devastating illness that affects mainly pine trees. It is known that the PWN is capable of infecting other conifers; however, there is currently no information on which other plant species may be susceptible to PWD. In this study, the potential susceptibility of two common species of European forests, Picea abies and Cupressus lusitanica, to PWN was assessed through the monitoring of visual external symptoms, dimension and localization of the nematode population in stems, quantification of total chlorophyll, total soluble phenolics and lignin, at 7, 14, 21 and 28days after inoculation. The degree of susceptibility was established through the comparison of symptoms with Pinus pinaster, a well-known PWN host. Furthermore, the stem ultrastructure of P.abies, C.lusitanica and Pn.pinaster was analysed by scanning electron microscopy. The results suggest that P.abies and C.lusitanica are resistant to PWN, and that lignin biosynthesis in these species is affected at an early stage of the infestation. Nevertheless, P.abies seems to be a compatible host that could act as a repository for PWN.