Study of Cyanogenic biosynthesis of bitter and sweet Almond (Prunus dulcis)‎

Cyanogenesis in Prunus species produces‎‏ ‏cyanogenic glycosides such as‏ ‏monoglycoside ‎Prunasin and digelicosede amygdalin. Despite the mechanism of almond bitterness inheritance ‎has been known, biosynthesis cycle of cyanogenic compounds among different genotypes is still ‎unclear. Total soluble proteins of fruits was extracted from collected sweet and bitter almond ‎genotypes and was studied using western immune blotting assay with Mandelonytril glycosidase ‎and related polyclonal antibody, and products of this enzyme was studied by HPLC. Results ‎showed that all of bitter and sweet genotypes had the ability of enzyme synthesis in the fruit and ‎it is produced since mid stage of fruit development. Only bitter genotypes kept synthesis the ‎enzyme and it was suppressed for sweet ones. The HPLC analysis of metabolites synthesized by ‎the enzyme showed that the amount of cyanogenic content of bitter genotypes was much more ‎than the sweet ones and merely in bitter genotype seeds prunasin content was reduced while ‎amygdalin content was gradually increased. This means bitter genotypes could accumulate ‎amygdalin in their seeds. ‎