Research & Innovation team profile

14 November, 2007

A key focus for Corbans Viticulture is the ongoing development of Research and Innovation. The research team is lead by Dr Anna Graham (BSc, MSc, PhD ). Together with the skills of Jason Shiller, Bevan Weir and associated NZ research bodies, Corbans Viticulture is developing new methods to provide the vine industry with improved plant material.

Findings have been presented at Bragato 2006, an International workshop on Grapevine trunk diseases at the UC Davis, California in 2006, at the Bragato nursery field trip in 2007 and at the Australasian Plant Pathology Symposium 2007. Further research will be presented by Bevan at the New Zealand Microbiological Society Conference, in Wellington later this month.

JASON SHILLER (B.SC)

Jason Shiller completed his Bachelor of Science (2004) and Post graduate diploma (2006) from the University of Auckland. In between these qualifications he worked as a technician in an analytical laboratory in Brisbane, Australia.

At present he is completing his Master’s degree research project at the University of Auckland, which has been funded by the Corbans Viticulture and Technology New Zealand. The main drive of his research is to develop a PCR test for the detection of fungal pathogens which cause young vine decline in grapevines. These pathogens include Eutypa lata (Eutypa dieback), Phaeomoniella chlamydospora (Petri disease), Phomopsis viticola (deadarm disease) and the group of Cylindrocarpon fungi responsible for black foot disease.

The symptoms of young vine decline are not apparent in vines during their first year in the nursery. The PCR test Jason has developed will allow for fast and cost effective identification of the fungi causing young vine decline. This could be used to randomly screen young vines in nurseries for fungal diseases prior to sale. This method can also be used to monitor the effectiveness of new sustainable methods for disease control such as hot water treatment and use of biological amendments as well as fungicides. So far Jason has developed two multiplex PCR tests that can diagnose several diseases at once. This has not been done before for the diseases previously mentioned. He is in the process of optimizing the test specifically for grapevine wood. It will provide a useful tool for nurseries, diagnostic labs and researchers alike.

BEVAN WEIR (BTech (Hons), PhD)

Bevan has a BTech degree in Biotechnology at the University of Auckland, and graduated with a PhD in 2006. His doctoral thesis examined the nitrogen-fixing soil bacteria known as “rhizobia” in native New Zealand legumes such as Kowhai and Kakabeak and compared findings with rhizobia in invasive legume weeds such as gorse and broom. Rhizobia have a symbiotic relationship with legumes; they fix nitrogen gas from the atmosphere to a form usable by plants, the plants in return make a root nodule “home” for the bacteria to live in and feed them nutrients. This symbiosis is exploited in agriculture to reduce nitrogen fertiliser use—for example clover in pasture—however this also allows invasive legume weeds such as gorse, broom, and wattles, to expand rapidly into marginal land. Bevan’s used PCR techniques to identify the rhizobia associated with the invasive legumes, and also the native legumes. The two groups had very different rhizobia, the species nodulating the invasive legumes were probably introduced from Europe.

Bevan is now using his knowledge and experience in PCR technology to study fungal populations in grapevines. A range of fungi also grow inside the grapevine, often several in each vine. Some species such as the Mycorrhizae are symbiotic, others as harmless endophytes and a few pathogenic species can cause vine decline diseases. Bevan is using a sophisticated DNA profiling technique called t-RLFP to develop a database of fungi (both pathogenic and harmless) living in grapevine wood. This t- RFLP technique can then be used to detect and identify all of the fungi living inside the wood with a single PCR test. Commercially available PCR diagnostic tests only identify one fungal species per test, and generally focus only on the harmful species. This test will allow us to see the bigger picture of whole fungal populations inside a vine.

His method will help answer ecological questions in the management of grapevines, for example how fungal populations change after using specific disease control treatments such as hot water treatment or fungicides. Changes in fungal populations, with different nursery and vineyard management systems or with climate change. The technique can also detect a range of species of pathogenic fungi present in grapevine wood, including those that cause young vine decline.