Journal of Plant Pathology
Volume 90 (2, Supplement) August 2008
An International Journal of the Italian Society for Plant Pathology
Formerly
Rivista di patologia vegetale
established in 1892
ICPP 2008 9th International Congress of Plant Pathology
Abstracts of invited and offered papers
Edited by A. Porta-Puglia and P. Gonthier
Torino, Italy, 24-29 August 2008 EDIZIONI ETS, Pisa, Italy Poste Italiane S.p.A. - Spedizione in Abbonamento Postale - D.L. 353/2003 (conv. in L. 27/02/2004 n° 46) art. 1, comma 1 - DCB AREA CENTRO 1/Pisa.
ISSN 1125-4653
S2.366
Journal of Plant Pathology (2008), 90 (2, Supplement), S2.81-S2.465
antigens of CGMMV and Tobacco mosaic virus (TMV), the two most commonly found tobamoviruses in Taiwan. A preliminary field survey using this antiserum showed that WT2-related viruses were widely distributed in watermelon, melon, wax gourd and bottle gourd. Poly(A)-tailed viral RNA of WT2 was used as template for cloning the 3’ region of the viral genome using primer pair (poly(T) and WT23: 5’-AA(A/G)TTTTT(T/C) TTTTATACTAG3’) in an rt-PCR. The sequence of the amplified DNA fragment contained 2152 nucleotides including partial replicase, movement protein (MP), coat protein (CP) genes and 3’ untranslated region (3’UTR). The sequence showed highest identities with Cucumber mottle virus (CMoV) (AB261167) when compared with known virus sequences in the GenBank. CmoV and WT2 shared 88% similarity in the MP, 87% similarity in the CP, and 82% identity in the 3’UTR. Based on these results, isolate of WT2 is probably a strain of CMoV.
frost. Thus P. radiata is an element of the landscape in the communities of Galicia, Asturias, Cantabria and the Basque Country, which latter grows 60 % of the P. radiata in Spain. Diplodia pinea is the most important pathogen of Pinus spp, causing serious problems in nurseries and specially in plantations in combination with two common meteorological factors in these regions: hail and strong wind. Here we report results of a hierarchical sampling in Spanish plantations of P. radiata. The diversity of the Spanish population of D. pinea was evaluated using the vegetative compatibility test, and compared with that of foreign isolates obtained from Chilean and New Zealand imported seed. The results showed high diversity in the D. pinea populations, due to the nature of the species and the introduction of new fungal isolates on pine seeds imported from other countries.
46.6 FARMERS PARTICIPATORY RESEARCH (FPR) FOR BIO46.4* PSEUDOMONAS ISOLATES FROM THE COCOYAM
LOGICAL MANAGEMENT OF BACTERIAL WILT OF TOMATO. D.K. Hazarika and J.K. Choudhary. Krishi Vigyan Kendra,
RHIZOSPHERE WITH QUORUM-SENSING MACHINERY HAVE ANTAGONISTIC PROPERTIES. K. De Maeyer, J. D’aes
Napaam, Tezpur, Assam, India. Email:
[email protected]
and M. Höfte. Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Coupure Links, 653, B-9000 Ghent, Belgium. Email:
[email protected]
Tomato is one of the important vegetables of Assam grow extensively as rabi crops. It suffers badly from bacterial wilt caused by Ralstonia solanacearum Yabuuchi. The disease causes considerable loss in yield, ranging from 10,8 to 92.62 per cent. In Assam, bacterial wilt is the most limiting factor for tomato as an early season crop. It is difficult to manage the disease with chemicals, and resistant cultivars fails to remain resistant for long. Bio control agents are the only solution to manage such soil borne pathogen and have several advantages over chemical control. Management strategy adopted in farmers field with active participation of farmers is a new approach for successful control of disease in sustainable manner. This new approach is based on learning by doing and believing by seeing. Keeping this in view, an experiment was conducted for three consecutive years in farmers field with commercial formulations of biocontrol agents containing Trichoderma viride, Trichoderma harzianum and Pseudomonas fluorescens obtained from Assam Agricultural University, Assam and Karnataka Agrochemicals Pvt Ltd., Bangalore. All biocontrol agents used as seed treatment as well as soil application or combination of both significantly reduced plant mortally and increased fruit yield over farmers own management practice. This effect was more prominent with combination of seed treatment and soil application. Highest reduction of plant mortality and increase in yield was recorded with Sparsha, a commercial formulation of Karnataka Agrochemicals Pvt Ltd containing P. fluorescens. By conducting such type of Farmers Participatory research a sustainable technology can be transferred from laboratory to field.
Among forty fluorescent pseudomonads randomly isolated from the rhizosphere of healthy cocoyam plants (Xanthosoma sagittifolium) in Cameroon, eight isolates showed antagonism against the cocoyam root-rot pathogen Pythium myriotylium. Seven of the eight antagonistic isolates were identified as producers of phenazine antibiotics. In addition, whole-cell protein profiling clustered these seven strains together with above 85% similarity. These strains may represent a novel Pseudomonas species. Quorum-sensing is a cell density-dependent regulation mechanism in which acylated homoserine lactones (AHLs) are autoinducers. Streak assays with different biosensor strains demonstrated AHL production only in these seven antagonistic, phenazine-producing strains. The ability to accumulate quorum-sensing signals distinguished the 7 antagonistic strains again from the 33 other rhizosphere isolates. This supports the assumption that population density-mediated gene expression is widespread in bacteria involved in plant-pathogen interactions. AHLs from these seven strains were profiled by thin-layer chromatography and biodetected by Agrobacterium tumefaciens NT1. Most strains produced more than one AHL, among which were 3-unsubstituted AHLs such as 3-oxo- or 3-hydroxy-substituted AHLs. Currently we are using mass spectrometry to identify these AHL derivatives. In particular we are interested in the quite rare 3-N-hydroxy/oxo-dodecanoyl homoserine lactone that is being produced by two strains.
46.5* DIPLODIA PINEA IN FOREST PLANTATIONS OF PINUS RADIATA IN NORTHERN SPAIN: DIVERSITY AND ORIGIN OF THE SPANISH POPULATION. I. Garcia-Serna, N. Mesanza and E. Iturritxa. Neiker Granja Modelo de Arkaute, Aptdo 46 Vitoria, Spain. Email:
[email protected] Pinus radiata is an exotic species first introduced in Spain at the end of the Nineteenth Century in private forests along with species like P. pinaster and Cupressus macrocarpa. An expansion of the P. radiata population took place during the forties and fifties. This rapid growth and desirable lumber and pulp qualities caused it to be the leading introduced species in the north of Spain. The domination of P. radiata is unquestionable, at altitudes lower than 600 m and in coastal areas, due to its susceptibility to
51.1* DIVERSITY OF PLANT HEALTH ISSUES IN HOME GARDENS. S. Helfer. Royal Botanic Garden Edinburgh, Scotland, UK. Email:
[email protected] By their very nature, private home gardens are diverse places of individual taste, and the choice of planting materials, their cultivation and protection are equally individualistic. It is therefore not surprising to find a large diversity of pathogens and pests in these gardens. The main components of plant health for home gardens are discussed, including plant type (trees, fruit, ornamentals etc.), pests and pathogens involved, control measures used or recommended. The available data are currently restricted to home gardens in the British Isles but it is hoped to expand the research to other areas, especially to subsistence horticulture in
