Promiscuous Arylsulfatase Activity in Chlamydomonas reinhardtii

Sulfate is an essential macroelement for all living organisms. However, sulfate can be limited in agricultural settings. Microorganisms change their gene expression to acclimate to sulfate deficient conditions. Green microalga Chlamydomonas reinhardtii expresses and secretes extracellular arylsulfatase (ARS) under sulfate deficient conditions. Our results show that C. reinhardtii ARS can hydrolyze both sulfate monoester (5-bromo-4-chloro-3 indolyl sulfate; X-SO42-) and phosphate monoester (5-bromo-4-chloro-3 indolyl phosphate; X-PO43-) providing evidence that ARS enzyme has promiscuous activity. C. reinhardtii is found in soil and fresh water habitats in nature. This promiscuous activity can be beneficial in making both sulfate and phosphate bioavailable for uptake by soil organisms and plant roots.