EUROPEAN JOURNAL OF PLANT PATHOLOGY
Volume 132 Number 1 January 2012
Host status of cultivated plants to Meloidogyne hispanica
Carla M N Maleita, Rosane H C Curtis, Stephen J Powers & Isabel Abrantes
The reproduction of a Meloidogyne hispanica isolate from Portugal was evaluated in 63 plant
species/cultivars, in pot assays at 25 ± 2.0°C, on the basis of root gall index (GI) and reproduction factor
(Rf = final/initial egg density) at 60 days after inoculation. Cultivars of aubergine, bean, beetroot, broccoli,
carnation, corn, cucumber, French garlic, lettuce, melon, onion, parsley, pea, potato, spinach, and tobacco and
two of cabbage were susceptible (3 ≤ GI ≤ 5; 1.15 ≤ Rf ≤ 262.86). Cabbage cv. Bacalan, cauliflower cv.
Temporão and pepper cv. Zafiro R2 were hypersusceptible or poor hosts (Rf < 1; GI > 2) and pepper cvs.
Aurelio and Solero were resistant (0.0 ≤ GI ≤ 0.4; 0.00 ≤ Rf ≤ 0.03). The response of the pepper cultivars and
the Mi-1 resistant tomato cv. Rossol was also conducted in pots using two inoculum levels and four
temperatures, three growth chamber (25 ± 2.7°C, 29.3 ± 1.8°C and 33.6 ± 1.2°C) and one outdoors
(24.4 ± 8.2°C). At 24.4 ± 8.2°C and 25 ± 2.7°C, the reproduction on the resistant tomato was significantly
lower compared to the susceptible cv. Easypeel. At all temperatures, resistance was evident for the pepper
cultivars, despite the fact they were not found to contain any of the Me1, Me3, Me7 and N genes. The eggs
obtained on cv. Aurelio at 33.6 ± 1.2°C were used to get a selected resistance breaking isolate of M. hispanica
that was able to reproduce on the three pepper cultivars. Our results suggest that the initial M. hispanica
isolate is a mixture of virulent and avirulent individuals. The pepper cultivars tested, have potential to reduce
M. hispanica populations in agro-ecosystems under certain conditions, but they should be used as a part of an
integrated management strategy in order to prevent the development of virulent populations.
http://www.springerlink.com/content/0929-1873/preprint/?sort=p_OnlineDate&sortorder=desc&o=10
Direct molecular detection of the pinewood nematode, Bursaphelenchus xylophilus, from pine
wood, bark and insect vector
Joana M S Cardoso, Luís Fonseca & Isabel Abrantes
The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease. The
international economic impact of the introduction of the PWN into new areas has highlighted the need for the
development of accurate and reliable detection methods of B. xylophilus, which are essential to define aspects
of its control and management. In the present study, a methodology was developed for the direct detection of
PWN by conventional PCR assay, with a species specific set of primers based on PWN satellite DNA, using
total DNA extracted directly from maritime pine, Pinus pinaster, wood and bark samples, and from the insect
vector, Monochamus galloprovincialis. This methodology involves homogenisation of wood, bark and insects
using liquid nitrogen, DNA extraction and one or two PCR amplification steps, which permit the rapid and
direct detection of one single nematode present in 100 mg of wood and bark and in one entire insect without
the preliminary steps of nematode extraction.
http://www.springerlink.com/content/0929-1873/preprint/?sort=p_OnlineDate&sortorder=desc&o=10
Identification of genes differentially expressed in Pinus pinaster and Pinus pinea after infection
with the pine wood nematode
Carla S S Santos & Marta W Vasconcelos
The purpose of this study was to compare the response to infestation by the pine wood nematode (PWN)
Bursaphelenchus xylophilus between Pinus pinaster and P. pinea at an initial stage of the disease, 3 h after
inoculation. The PWN is the causal agent of pine wilt disease and is destroying pine forests all over the world.
In Portugal its main host is the maritime pine, P. pinaster, and its vector is the longhorn beetle Monochamus
galloprovincialis. Interestingly, this disease does not seem to affect the species P. pinea and several factors
could be behind this difference in susceptibility. With regards to the effects of the disease at a transcriptional
level, the suppression subtractive hybridization (SSH) technique was utilized to identify Expressed Sequence
Tags (EST) in P. pinaster and P. pinea when inoculated with PWN. EST were isolated, cloned, sequenced and
identified using BlastN and BlastX, and indicated that at an initial stage of the disease there is activation of a
tree defence response at a molecular level, mainly related to oxidative stress, production of lignin and ethylene
and post-transcriptional regulation of nucleic acids. 58% of the isolated sequences are not yet described,
which shows the lack of genomic information currently available for pine.
(Not available PDF through Open Access)