Abstracts
edges were analysed, results showed that there were significantly greater lengths below than above inoculation points for all combinations (P≤0.05). In addition, co-inoculation of two weakly virulent isolates reduced upward movement (P≤0.05). A decrease in the endophytic movement of N. luteum beyond the lesion was also observed in all co-inoculations. Overall, the results demonstrated that there were no synergistic effects of co-inoculation with these two common species. The genetic structure of Botryosphaeriaceae isolated from vineyards in south eastern Australia as revealed by molecular markers. Y. QIU, C.C. STEEL, G.J. ASH and S. SAVOCCHIA*. National Wine and Grape Industry Centre, Charles Sturt University, School of Agricultural and Wine Sciences, Locked Bag 588, Wagga Wagga NSW 2678 Australia. *E-mail:
[email protected] Genetic variation within four species of Botryophaeriaceae isolated from south eastern Australian vineyards (Lower and Upper Hunter Valley and Mudgee) was investigated using a hierarchical sampling and a range of PCR primers. A set of 100 primers (Microsatellite Primer Set #9; Biotechnology laboratory, University of British Columbia, Canada), (ACC)5, R1 (consensus region from a plant intron splice junction) and M13 (core sequence of the M13 minisatellite region) primers were screened with a selection of isolates from all four species. Of these, five of the 100 primer set, (ACC)5, M13 and R1 were selected and resulted in 280 highly reproducible polymorphic bands across 127 Diplodia seriata, 23 Neofusicoccum parvum, 18 Botryosphaeria dothidea and three Lasiodiplodia theobromae isolates. Cluster analysis with the integrated locus matrix separated the isolates into four distinguishable groups according to species (cophenetic correlation = 0.97). Within D. seriata differentiation by region was evident. Furthermore, for this species there was variation in genotype between vineyards in several instances. Isolates of N. parvum showed greater homogeneity between vineyards and regions, while B. dothidea showed homogeneity between regions from which they were isolated (Lower and Upper Hunter Valley). The results obtained in this study were effective in determining the genetic variation within the Botryosphaeriaceae species examined and could be used to guide sampling in future surveys and population studies. Ocurrence of Phaeomoniella chlamydospora in Vitis vinifera and V. labrusca vineyards of the Serra Gaúcha region of the Rio Grande do Sul state in southern Brazil. M.A.K. ALMANÇA1,*, C. RUSIN1, G. GIOTTO1, G.T. MARTINELI1, M.R. DE OLIVEIRA1 , F.R. CAVALCANTI2 and F. HALLEEN3. 1 Rio Grande do Sul Education, Science and Technology Federal Institute, Osvaldo
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Phytopathologia Mediterranea
Aranha Avenue, 540, Zip Code 95700-000 Bento Gonçalves, Rio Grande do Sul, Brazil. 2 Embrapa Grape & Wine, Livramento Street, 515, Bento Gonçalves, Rio Grande do Sul, Brazil. 3 Plant Protection Division, ARC Infruitec-Nietvoorbji, Private Bag X5026, Stellenbosch, 7599, South Africa. *Email:
[email protected] Several factors affect the quantity and quality of grapevine production in Brazil. This includes the grapevine decline phenomenon and the various disease complexes associated with it. For example, in Brazil, there is very little knowledge about Esca and Petri disease and the distribution of the pathogens associated with it. The objective of this research was to study Phaeomoniella chlamydospora (Pchl) distribution in different cultivars and plant parts from vineyards in the Serra Gaúcha region of the Rio Grande do Sul state in southern Brazil. Grapevines with decline symptoms were collected in 21 vineyards and taken to the laboratory for destructive sampling and analysis. Vitis vinífera cultivars included Chardonnay (14 plants), Merlot (1) and Cabernet Sauvignon (7). Vitis labrusca cultivars included Isabel (1 plant), Bordô (10) and Niágara (4). Isolations were made from symptoms in spurs, arms, upper part of the trunk, graft union and basal end of the rootstock. Pchl incidences ranged from 2.5 to 27.4% in V. labrusca and 4.8 to 8.8% in V. vinifera. From the different plant parts Pchl incidences ranged from 7.3 to 13.1%. From the different internal symptoms, Pchl was most frequently isolated from black spotting (17.1 %) and soft and spongy rotted wood (15.4%), followed by brown-red wood (7.8%), black line (7%) and wedge shaped necrosis (6.3%).
Host Pathogen Interaction Induction of grapevine defence systems using the oomycete Pythium oligandrum against a pathogenic fungus involved in Esca. A. YACOUB1,2,3, J. GERBORE4, N. MAGNIN1,2, J. VALLANCE2,1, D. GRIZARD4, R. GUYONEAUD3 and P. REY2,1,*. 1INRA, UMR1065 Santé et Agroécologie du Vignoble (SAVE), ISVV, F-33140 Villenave d’Ornon, France. 2Université de Bordeaux, Bordeaux Sciences Agro, ISVV, UMR1065 SAVE, F-33140 Villenave d’Ornon, France. 3UMR CNRS 5254/IPREM-EEM, IBEAS, Université de Pau et des Pays de l’Adour, 64013Pau, France. 4 BIOVITIS, 15400 Saint Etienne de Chomeil, France. *Email:
[email protected] The oomycete, Pythium oligandrum, has been reported to control several diseases and is able to induce plant defense systems. In order to control grapevine diseases, we isolated P. oligandrum strains from the rhizosphere of vines cultivated in 12 vineyards of the Bordeaux region. Pythium spp. with echinulated-oospores were frequently isolated from the root system of the sampled vines, with P. oligandrum being the most frequently identified species (91% of strains, analyses based on ITS
