Cell differentiation by 3',5'-cyclic AMP in a lower plant

Abstract

Cyclic AMP evokes or mediates a multitude of responses in animals and microorganisms. Whereas the occurrence and regulatory role of cyclic AMP in these organisms is well established, little is known about its role in plants. Cyclic AMP has been reported to mimic certain effects of gibberellins, indoleacetic acid (IAA) and phytochrome in higher plants but in no case has its endogenous presence been unequivocally demonstrated. We describe here a new response of cyclic AMP at the cellular level in the moss protonema; the results show that it is involved in the differentiation of chloronema cells. The intracellular level of cyclic AMP in these cells is four- to sevenfold higher as compared with that in caulonema cells. In a leaky chloronema-repressed mutant isolated by us, cyclic AMP is shown to enhance the differentiation of chloronema filaments.