A Unifying Xenobiotic Theory of Metabolic Diseases in Plants and Humans: The Role of Microbial Chiral Amino Acids

A novel evidence-based theory is offered that proposes microbial D-amino acids as evolutionarily-conserved interkingdom stress signals by lower life forms such as soil or gut microbiota serving as front-line ecological microsensors for plants and humans. These D-amino acids seem to act as metabolic switches that biochemically link xenobiotic stress to pathological disruptions in plant and human metabolisms and defense/immune systems. D-amino acids and peptides, by impairing chirally-sensitive hormones/phytohormones and mitochondrial and photosynthetic complexes, are able to disrupt the Krebs and photosynthetic cycles and switch cellular metabolism in higher life forms from orderly, oxidative and ATP-efficient, to microbial, reductive and ATP-deficient with low quantum yield. The hypothesis links the lower electron transfer efficiency in heterochiral peptides, where D-amino acids partially replace L-analogs, to photosynthetic/mitochondrial dysfunctions and diseases.