Iron deficiency influences NtcA-dependent regulation of fatty acid desaturation and heterocyte envelop formation in Anabaena sp. PCC 7120.

Abstract

In Anabaena sp. PCC 7120, iron is an essential trace element and its availability determines proper functioning of several kinds of metabolisms. Iron deficiency leads to several unavoidable consequences including membrane damage. In the present study, we dealt with the impact of iron deficiency on NtcA (global nitrogen regulator)-dependent regulation of two important processes, i.e. fatty acid desaturation and heterocyte envelop formation in cyanobacterium Anabaena sp. PCC 7120. In Anabaena sp. PCC 7120, NtcA regulates fatty acid desaturation by regulating enzyme fatty acid desaturases. The NtcA-based regulation of fatty acid desaturation may be direct or indirect. Furthermore, the expression of genes involved in the heterocyte envelope polysaccharide (HEP) layer formation (hepABCK) and heterocyte-specific glycolipids (HGLs) synthesis (devH, hglEA , prpJ and devB) were also under the control of NtcA and reduced under iron deficiency background. The enhanced expression of furA and early downregulation of ntcA under iron deficiency is responsible for reduction in fatty acid desaturation as well as decrease in the expression of genes involved in HEP layer formation and HGL synthesis. Overall results confirmed that iron deficiency influences the NtcA-based regulation of fatty acid desaturation and heterocyte envelop formation in Anabaena sp. PCC 7120.