Pyrroloquinoline quinone (PQQ): Role in Plant-Microbe Interactions

Abstract

Pyrroloquinoline quinone (PQQ) is synthesized by only some bacteria, but it has an impact on many organisms, including plant growth-promoting bacteria. This molecule can modify some microbial process such as gene expression, metabolism, among others, which have potential advantageous effects on plants. We describe the conditions and factors that influence the synthesis of PQQ, its functions as an enzymatic cofactor in many reactions, and how it promotes plant growth by phosphate solubilization in soils. We also describe its actions in the synthesis of antimicrobials and its influence on the biocontrol of fungi and bacteria that are pathogenic to plants. PQQ also has a role in the induction of systemic resistance in plants and the molecule may help in the metabolism of other bacteria, promoting a kind of bacterial mutualism. PQQ can also modify gene expression through signal transduction systems and combat stress induced by ultraviolet and gamma radiation, as well as serving as a powerful agent against oxidative stress and perhaps influencing bacterial motility.