β-Cyclocitral, a volatile oxidized derivative of β-carotene, is a grazer defence signal unique to the Cyanobacterium Microcystis. β-Cyclocitral, one of the predominant volatile terpenoid compounds, can upregulate the expression of defence genes to enhance excess light (EL) acclimation. β-Cyclocitral is a powerful repellent[1][2][3].
β-Cyclocitral is derived from the catalytic breakdown of β-carotene, and evidence indicates that it is produced by the activation of a specific carotene oxygenase by all species of the bloom-forming cyanobacterium Microcystis. β-cyclocitral affects grazer behavior[3].
[1]. Alexandra J Dickinson, et al. β-Cyclocitral Is a Conserved Root Growth Regulator. Proc Natl Acad Sci U S A. 2019 May 21;116(21):10563-10567.
[2]. Feifei Lv, et al. β-Cyclocitral Upregulates Salicylic Acid Signalling to Enhance Excess Light Acclimation in Arabidopsis. J Exp Bot. 2015 Aug;66(15):4719-32.
[3]. Friedrich JÜttner, et al. β-Cyclocitral, a Grazer Defence Signal Unique to the Cyanobacterium Microcystis. J Chem Ecol. 2010 Dec;36(12):1387-97.