QuantificationofCyclicDinucleotidesbyReversedPhaseLCMS／MS

Cyclic dinucleotides such as bis-(3′,5′)-cyclic dimeric adenosine monophosphate (c-di-AMP) and bis-(3′,5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) represent important second messengers in bacteria. Although their synthesis has not been described in plants so far, they may be involved in the regulation of bacterial phytopathogen–plant interactions as well as rhizobium plant symbiosis. Here, we describe a sensitive and specific quantification method for c-di-AMP and c-di-GMP by HPLC-coupled tandem mass spectrometry. Additional linear dinucleotide metabolites and mononucleotides, as well as cyclic mononucleotides, can be simultaneously determined by this method.