| Abstrakt: |
d‐amino acids are the d stereoisomers of the common l‐amino acids found in proteins. Over the past two decades, the occurrence of d‐amino acids in plants has been reported and circumstantial evidence for a role in various processes, including interaction with soil microorganisms or interference with cellular signalling, has been provided. However, examples are not numerous and d‐amino acids can also be detrimental, some of them inhibiting growth and development. Thus, the persistence of d‐amino acid metabolism in plants is rather surprising, and the evolutionary origins of d‐amino acid metabolism are currently unclear. Systemic analysis of sequences associated with d‐amino acid metabolism enzymes shows that they are not simply inherited from cyanobacterial metabolism. In fact, the history of plant d‐amino acid metabolism enzymes likely involves multiple steps, cellular compartments, gene transfers and losses. Regardless of evolutionary steps, enzymes of d‐amino acid metabolism, such as d‐amino acid transferases or racemases, have been retained by higher plants and have not simply been eliminated, so it is likely that they fulfil important metabolic roles such as serine, folate or plastid peptidoglycan metabolism. We suggest that d‐amino acid metabolism may have been critical to support metabolic functions required during the evolution of land plants. Summary statement: d‐amino acids are d enantiomers of natural, l‐amino acids. Their metabolism is still incompletely known and here, we review how it is linked to the origin of higher plants. [ABSTRACT FROM AUTHOR] |
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