Lipoxygenases (LOXs) are a group of non-haem iron-containing dioxygenases that catalyse oxygenation of polyunsaturated fatty acids (PUFAs) and lipids, and initiate the formation of biologically active compounds known as oxylipins. Several plant oxylipins comprise important flavours and aromas in food and beverages. Analysis of the grape (Vitis vinifera L.) genome revealed that the grape LOX family consists of 18 individual members. Phylogenetic analysis places all except one of the identified grape LOXs into either a type II 13-LOX cluster or the type I 9-LOX cluster. Four LOX genes (VvLOXA, VvLOXO, VvLOXC, VvLOXD), representative of the major LOX groupings observed in the phylogenetic analyses, were selected for analysis of patterns of transcript abundance in berry tissues. VvLOXA and VvLOXO represent putative 13-LOXs, while VvLOXC represents a putative 9-LOX. VvLOXD represents a unique LOX that differs significantly from other characterised plant LOXs. All four LOXs exhibited a complex pattern of gene expression. Across all developmental stages, VvLOXA was the most abundant LOX and was expressed predominantly in berry skins. The expression pattern of VvLOXC and -D are more evenly distributed between seeds, pulp and skin, while VvLOXO is mostly expressed in the seed. Mechanical wounding and infection of berries with Botrytis cinerea Pers.: Fr resulted in rapid accumulation of VvLOXC and -O transcripts. VvLOXA expression decreased in diseased berries. Biochemical analysis of VvLOXA and -O recombinant proteins confirmed that these LOX genes encode functional 13-LOXs that exhibit different pH and temperature optima. Both enzymes showed activity with linoleic, linolenic and arachidonic acids.

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Purpose The nitrification inhibitor dicyandiamide (DCD) has been shown to be highly effective in reducing nitrate (NO 3 − ) leaching and nitrous oxide (N 2 O) emissions when used to treat grazed pasture soils. However, there have been few studies on the possible effects of long-term DCD use on other soil enzyme activities or the abundance of the general soil microbial communities. The objective of this study was to determine possible effects of long-term DCD use on key soil enzyme activities involved in the nitrogen (N) cycle and the abundance of bacteria and archaea in grazed pasture soils. Materials and methods Three field sites used for this study had been treated with DCD for 7 years in field plot experiments. The three pasture soils from three different regions across New Zealand were Pukemutu silt loam in Southland in the southern South Island, Horotiu silt loam in the Waikato in the central North Island and Templeton silt loam in Canterbury in the central South Island. Control and DCDtreated plots were sampled to analyse soil pH, microbial biomass C and N, protease and deaminase activity, and the abundance of bacteria and archaea. Results and discussion The three soils varied significantly in the microbial biomass C (858 to 542 μg C g does not affect other non-target microbial and enzyme activities. The DCD nitrification inhibitor technology, therefore, appears to be an effective mitigation technology for nitrate leaching and nitrous oxide emissions in grazed pasture soils with no adverse impacts on the abundance of bacteria and archaea and key enzyme activities.

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