Plant-pathogen interactions
Science programme: Plant-pathogen interactions
New Zealand’s mild, humid climate is highly conducive for the occurrence of both pre- and post-harvest diseases of fruit crops. Diseases are a problem for all of our main horticultural clients, but for the pipfruit and winegrape industries in particular fungal diseases are a significant cost. At the same time consumer acceptance of the weapon most used against fungi, chemical fungicides, is decreasing significantly. In addition, fungi have become resistant to many of the main classes of fungicides that we use.
Clearly new approaches to controlling diseases are required. Our team is focusing on two approaches:
- Better understanding and utilisation of the genetic basis of disease resistance. One of HortResearch’s sustainable, competitive advantages is its germplasm collections. Within these collections reside a considerable genetic resource for pathogen resistance.
- Discovering new methods for controlling diseases. New control methods, particularly those that are natural products, have an advantage in the market place.
The genetic basis for disease resistance
Plants possess genes that confer resistance to specific pathogens. If particular cultivars lack some of these genes they are susceptible to a particular disease. Apple is a good example where our commercial cultivars tend to lack genetic resistance to the most common fungal diseases such as powdery mildew and black spot. However, there is genetic resistance in non-commercial cultivars including our Kazakhstan germplasm collection. A major goal of the apple breeding programme is to incorporate specific disease resistance into new apple cultivars. Our team is contributing by identifying and cloning genes specific for powdery mildew and black spot.
New methods for controlling diseases
We are currently looking to commercialize two new products with activity against plant pathogens. The first is a milk-based product that is active against a number of fungal diseases particularly mildews. This compound is particularly effective and patent applications have been filed.
The second product is a compound that is specifically active against the bacterium that causes fire-blight on apple. This is an important disease not just because of its effect on apple orchards but because it is a disease with market access issues. We are currently evaluating this compound in blossom trials.
Contact Matt Templeton
Selected publications:
Wurms, K. V. (2005). "Susceptibility to Botrytis cinerea and curing-induced responses of lytic enzymes and phenolics in fruit of two kiwifruit (Actinidia) cultivars. "
New Zealand Journal of Crop and Horticultural Science 33(1): 25-34.
Mitchell, R. and K. Teh (2005). "Antibacterial iminopyrrolidines from Burkholderia plantarii, a bacterial pathogen of rice." Organic & Biomolecular Chemistry on web: 1-2.
MacDiarmid, R. (2005). "RNA silencing in virus infections." Annual Review Phytopathology 59.
Bus, V. G. M., E. H. A. Rikkerink, et al. (2005). "The Vh2 and Vh4 scab resistance genes in two differential hosts derived from Russian apple R12740-7A map to the same linkage group of apple." Molecular Breeding 15: 103-116.
Bus, V. G. M., F. N. D. Laurens, et al. (2005). "The Vh8 locus of a new gene-for-gene interaction between Venturia inaequalis and the wild apple malus sieversii is closely linked to the Vh2 locus in Malus pumila R12740-7A." New Phytologist 166(3): 1035-1049.
Templeton, M. D., L. A. Reinhardt, et al. (2005). "Kinetic Analysis of the L-Ornithine Transcarbamoylase from Pseudomonas savastanoi pv. phaseolicola that is Resistant to the Transition State-Analogue (R)-Nd-(N'-Sulfodiaminophosphinyl)-L-Ornithine." Biochemistry 44(11): 4408-4415.
Schmidt, K., S. Chand , et al. (2005). "Fungal Inoculum Properties and Its Effect on Growth and Enzyme Activity of Trametes versicolor in Soil." Biotechnology Progress 21: 377-385.
|
