S. Savocchia

Laccases are one of many groups of inducible enzymes produced by the filamentous fungus, <i>Botrytis cinerea</i> during colonisation of host plant tissues. While the processes involved in laccase induction are not fully understood, Cupric ions (e.g. CuSO<sub>4</sub>) and gallic acid (GA) have been reported as laccase inducers. This study investigates laccases activities and the expression of three laccase genes (<i>BcLCC1, BcLCC2, BcLCC3</i>) in three <i>B. cinerea</i> isolates grown in laccase-inducing medium (LIM) supplemented with CuSO<sub>4</sub> and GA. Laccase activity in culture filtrates with CuSO<sub>4</sub> increased after 48 h of growth in LIM at 24°C. The induction of <i>BcLCC2</i> transcription was greatest at a concentration of 0.6 mM CuSO<sub>4</sub>, concentrations greater than 0.6 mM inhibited fungal growth. In contrast, no laccase induction was observed in the presence o...

From 2002 to 2004, vines from 11 vineyards in the Hunter Valley region and from 4 vineyards in Mudgee (New South Wales, Australia) were inspected for foliar and wood symptoms of Eutypa dieback and Botryosphaeria canker. Eutypa lata was not isolated, however species of Botryosphaeria were frequently isolated from dead and declining spurs, cordons and trunks. Two species conforming to the anamorphs of Diplodia and Fusicoccum were isolated. Cultures on PDA producing a yellow pigment, and hyaline aseptate conidia (14-23.5 x 8-13 μm in size) were identified as B. lutea. Cultures with dark brown, 1-septate, ornamented conidia (15-25 x 8-14 μm in size) at maturity were identified as B. obtusa. Pathogenicity tests were conducted on detached green shoots, detached one-year-old canes and glasshouse-grown grapevines. In all situations, disease symptoms were reproduced and Koch's postulates were fulfilled. The results demonstrate the potential of B. obtusa and B. lutea as primary pathogens ...

Background and Aims. Fumonisins are a group of mycotoxins produced by some isolates of black aspergilli. This study examines the dynamics of fumonisins during winemaking and storage and the role of fining agents in the removal of FB2, the most prevalent fumonisin produced by black aspergilli. Methods and Results. Chardonnay grapes were inoculated with a fumonisin-producing strain of Aspergillus welwitschiae and fumonisins were quantified at different stages of vinification. The stability of fumonisins was studied at 13 and 25°C using Chardonnay wine spiked with FB2. Activated charcoal, calcium bentonite, yeast hulls, and a nonallergenic polysaccharide of nonanimal origin (NO (OX)) were evaluated as fining agents for FB2 removal from wine. Fumonisins were quantified by LC-MS/MS. During vinification most of the fumonisins were removed with the solids, with only 3% of the fumonisins found in the grapes being transferred to the wine. Fumonisin FB2 was stable in white wine for at least 4...

Colletotrichum acutatum , the casual agent of ripe rot in tropical and sub-tropical grape growing regions of Australia, affects crop yield and wine quality. To elucidate the epidemiology of the fungus, its presence was studied on shoots, pea sized and mature berries, mummified bunches, spurs and canes during two consecutive growing seasons and one winter season. The presence of C. acutatum was analysed by both traditional and real-time PCR methods. A protocol was developed to achieve PCR amplification for fungal DNA extracted from 'difficult' wood samples. C. acutatum was detected on mature berries, mummified berries, the peduncles of mummified berries, winter spurs and canes but not on the remaining analysed tissues. Thus the fungus overwinters on Vitis vinifera plant tissues and the conidia on spurs and dormant wood are likely to be the most important source of primary inoculum for the next growing season.

... Utrecht, The Netherlands; ATCC, American Type Culture Collection, Manassas, Virginia, USA; IMI, CABI Bioscience (formerly, International Mycological Institute), Oxfordshire, United Kingdom; CMW, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria ...

Black aspergilli are some of the most common mycotoxigenic fungi in vineyards worldwide. The aims of this research were to assess the occurrence of fumonisin-producing black aspergilli in Australian wine grapes and the effects of environmental factors on fumonisin production by A. niger and A. welwitschiae (syn. A. awamori). Thirty-eight Aspergillus isolates (black aspergilli) were collected from six wine grape varieties grown in Australian vineyards. LC-MS/MS analysis of culture extracts revealed that six isolates produced fumonisins FB2 and FB4. Molecular data revealed that all fumonisin-producing isolates were A. niger and A. welwitschiae. None of the reference isolates, A. carbonarius, A. tubingensis, A. japonicus, and A. foetidus, were positive for fumonisin production. The effects of temperature and water activity on the growth and production of fumonisins were studied using two A. niger and an isolate of A. welwitschiae on synthetic grape juice medium (SGJM) at 20 °C, 25 °C, 30 °C, and 35 °C, and 0.92 aw, 0.95 aw, and 0.98 aw levels. All isolates produced FB2 and FB4 at 0.95 aw and 0.98 aw and 20 °C, 25 °C, and 30 °C. The highest growth rate observed was 14.89 mm/day for A. welwitschiae at 0.98 aw and 35 °C, whereas the highest fumonisin production observed was 25.3 mg/kg at 0.98 aw and 20 °C for A. welwitschiae. None of the isolates produced fumonisins at 35 °C at any water activity levels. To our knowledge, this is the first report on the occurrence of fumonisin-positive isolates of Aspergillus from Australian wine grapes and the impact of the environmental factors on fumonisin production by A. welwitschiae.

... Plant Dis. 82: 452-464. Buchanan, T. 2000. The efficacy of a World-Wide Web mediatedformative assessment. J. Computer Assisted Learning 16: 193-200. Bureau of Meteorology 2004. www.bom.gov.au/climate/ Crisp, P., Scott, E. and Wicks, T. 2003. ...

The National Wine and Grape Industry Centre has employees in research, education, training and extension. This team approach has resulted in rapid uptake of new research. The research scientists in the team have studied the distribution, taxonomy, epidemiology and management of the grapevine trunk disease, Botryosphaeria canker. The results have been presented to the wine grape industry using adult education and extension principals as part of existing university courses and at training days for winegrape growers. The incidence and distribution of grapevine trunk disease fungi were surveyed for the major winegrape growing regions of New South Wales and South Australia. The most prevalent species isolated were those belonging to the Botryosphaeriaceae. Other fungi isolated included Eutypa lata, Phaeomoniella chlamydospora, Phaeoacremonium spp. and Phomopsis viticola. No fungicides are currently registered for the control of Botryosphaeria canker in Australian vineyards however, in vi...

ABSTRACT Background and AimsSpecies of Botryosphaeriaceae have been reported in association with various grapevine diseases, such as trunk diseases and fruit rots worldwide. Their distribution, however, has not been thoroughly studied at the genetic level. The aim of this study was to evaluate genetic variation within four species of Botryosphaeriaceae isolated from south-eastern Australian vineyards at several geographical scales.Methods and ResultsFungal isolates were taken using a hierarchical methodology. A range of polymerase chain reaction (PCR) primers, including a selected set of six inter-simple sequence repeat primers, the intron splice junction R1 primer and the M13 core sequence microsatellite primer, were selected after preliminary screening. A total of 171 isolates of the Botryosphaeriaceae was assessed, comprising 127 Diplodia seriata, 23 Neofusicoccum parvum, 18 Botryosphaeria dothidea and 3 Lasiodiplodia theobromae isolates from three closely located regions. From these, 280 highly reproducible polymorphic bands were detected across all isolates following PCR. Intra- and inter-specific differences were visualised as a dendrogram and a principle coordinates plot. Cluster analysis with the integrated locus matrix separated the isolates into four distinguishable groups according to species (cophenetic correlation = 0.97).Conclusions Our study indicates that genetic differentiation by region was evident within D. seriata, and 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.Significance of the StudyThe degree of variation in populations of Botryosphaeriaceae in vineyards indicated in this study can be helpful in the future for controlling the spread of the pathogen in Australian vineyards and can be used to guide sampling in future surveys and population studies of the genus. The unique banding patterns of each species detected in this study can be utilised in the future for designing species-specific primers, which would enable in-field real-time detection of Botryosphaeriaceae without destructive sampling.

... To complement this resistance breeding, the mechanisms * Corresponding author, e-mail:tricia.franks@adelaide.edu.au 1 ... 1A). Mature females (mean 36.8, standard deviation (sd) 20.0,range 6-98) and egg masses (Fig. 1B) were observed in roots of all Chardonnay plantlets. ...