Resistance to arsenate toxicity in the blue-green alga Synechococcus leopoliensis

Phosphate-limited growth of the blue-green alga Synechococcus leopoliensis was unaffected by arsenate at up to 200 μM. Phosphate uptake, during growth and also under nongrowing conditions, was not measurably affected by arsenate even at 50 × the phosphate concentration. Arsenate uptake was very low and was not influenced by light or by external phosphate. It is concluded that phosphate transport in Synechococcus is highly phosphate specific. The ecological aspects of this specificity are briefly discussed.