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Cyclic di-adenosine monophosphate (c-di-AMP) is a bacterial second messenger discovered in <i>Bacillus subtilis</i> and involved in potassium homeostasis, cell wall maintenance and/or DNA stress response. As the role of c-di-AMP has been mostly studied in Firmicutes, we sought to increase the understanding of its role in Actinobacteria, namely in <i>Corynebacterium glutamicum</i>. This organism is a well-known industrial production host and a model organism for pathogens, such as <i>C. diphtheriae</i> or <i>Mycobacterium tuberculosis</i>. Here, we identify and analyze the minimal set of two <i>C. glutamicum</i> enzymes, the diadenylate cyclase DisA and the phosphodiesterase PdeA, responsible for c-di-AMP metabolism. DisA synthesizes c-di-AMP from two molecules of ATP, whereas PdeA degrades c-di-AMP, as well as the linear degradation intermediate phosphoadenylyl-(3′→5′)-adenosine (pApA) to two molecules of AMP. Here, we show that a <i>ydaO/kimA</i>-type c-di-AMP-dependent riboswitch controls the expression of the strictly regulated cell wall peptidase gene <i>nlpC</i> in <i>C. glutamicum</i>. In contrast to previously described members of the <i>ydaO/kimA</i>-type riboswitches, our results suggest that the <i>C. glutamicum nlpC</i> riboswitch likely affects the translation instead of the transcription of its downstream gene. Although strongly regulated by different mechanisms, we show that the absence of <i>nlpC</i>, the first known regulatory target of c-di-AMP in <i>C. glutamicum</i>, is not detrimental for this organism under the tested conditions.