CLONING AND CHARACTERIZATION OF APPLE LIPOXYGENASE (LOX) GENES PUTATIVELY INVOLVED IN THE FORMATION OF FRUIT FLAVOUR VOLATILES

Lipoxygenases (LOXs) belong to an enzyme class that is ubiquitous in eukaryotes and by oxygenation of unsaturated fatty acids provide precursors that play a decisive role in the volatile production and pathogen resistance in apple (Malus × domestica Borkh.). The first bioinformatic LOX gene mining in Malus sequence databanks and in the whole ‘Golden Delicious’ genome sequence resulted in the identification of about 40 different apple LOX sequences.
After a second round of screening for putative functional genes, a phylogenetic tree of the LOX gene family in Malus, including 29 sequences, was calculated.
Two sub-trees were found which differentiate the LOX sequences according their positional specificity of linoleic acid oxygenation.
In some cases, the position of putative LOX genes belonging to the same group was in agreement with the reported collinearity of apple chromosomes.
To obtain full-length apple LOX genes, more than 100 LOX sequences from seven different genes were amplified by PCR and sequenced.
To date, 26 complete nucleotide sequences were obtained and assigned to LOX genes identified bioinformatically.
A proposal for nomenclature of the apple LOX gene family members is presented.

XIII Eucarpia Symposium on Fruit Breeding and Genetics

J. Vogt, D. Schiller, W. Schwab, F. Dunemann

Malus, aroma, candidate gene, gene family, LOX taxonomy

https://doi.org/10.17660/ActaHortic.2013.976.50