Cyanogenic Glucosides and Derivatives in Almond and Sweet Cherry Flower Buds from Dormancy to Flowering

Abstract

Almond and sweet cherry are two economically important species of the Prunus genus. They both produce the cyanogenic glucosides prunasin and amygdalin. As part of a two-component defense system, prunasin and amygdalin release toxic hydrogen cyanide upon cell disruption. In this study, we investigated the potential role within prunasin and amygdalin and some of its derivatives in endodormancy release of these two Prunus species. The content of prunasin and of endogenous prunasin turnover products in the course of flower development was examined in five almond cultivars – differing from very early to extra-late in flowering time – and in one sweet early cherry cultivar. In all cultivars, prunasin began to accumulate in the flower buds shortly after dormancy release and the levels dropped again just before flowering time. In almond and sweet cherry, the turnover of prunasin coincided with increased levels of prunasin amide whereas prunasin anitrile pentoside and β-D-glucose-1-benzoate were abundant in almond and cherry flower buds at certain developmental stages. These findings indicate a role for the turnover of cyanogenic glucosides in controlling flower development in Prunus species.

Elucidation of the Amygdalin Pathway Reveals the Metabolic Basis of Bitter and Sweet Almonds (Prunus dulcis)

“…No evidence for the localization of a cyanogenic glucoside biosynthetic cluster around PdCYP79A68 was found, and the gene is expressed neither in the tegument nor in the cotyledons. Recently, a potential signaling role of prunasin and of endogenous prunasin turnover products in endodormancy release in almond and sweet cherry was reported (Del Cueto et al, 2017;Ionescu et al, 2017aIonescu et al, , 2017b. In sweet cherry cultivars, PaCYP79A68 displayed a high level of expression during dormancy release.…”

“…In sweet cherry cultivars, PaCYP79A68 displayed a high level of expression during dormancy release. This was echoed by an observed accumulation of prunasin in the flower buds shortly after dormancy release, and the levels dropped again just before flowering time (Del Cueto et al, 2017). In sweet cherry and other Prunus species, treatment with the agrochemical hydrogen cyanamide has been used routinely to induce the breaking of dormancy to advance flowering time (Ionescu et al, 2017a(Ionescu et al, , 2017b.…”

Counting the costs: nitrogen partitioning in Sorghum mutants

“…Kongsawadworakul et al 2009). In Prunus species, cyanogenic glucoside formation and turnover are involved in controlling floral bud break (Del Cueto et al 2017;Ionescu et al 2017aIonescu et al , 2017b.…”

Mechanisms in mutualisms: a chemically mediated thrips pollination strategy in common elder

“…Therefore, CNglcs in the floral tissue of S. nigra may play a role in protecting unopened flower buds and developing fruit from potential florivores. While we can postulate that defence of valuable tissues is the primary role of CNglcs, the multifunctionality of these compounds as a source for sugars and reduced nitrogen for the physiological changes that occur during the reproductive stages (Selmar et al 1988;Neilson et al 2013;Del Cueto et al 2017) has not been considered here. To ameliorate the costs of chemical defence, secondary metabolites that initially served defence purposes may acquire new functions in host-insect recognition or be recruited as storage compounds that are mobilized when needed to counteract imbalances in primary metabolism (Zagrobelny et al 2008).…”