The cyanobacterium, <i>Nostoc punctiforme</i> can protect against programmed cell death and induce defence genes in <i>Arabidopsis thaliana</i>

Cyanobacteria can form nitrogen-fixing symbioses with a broad range of plant species. Unlike other plant-bacteria symbioses, little is understood about the immunological responses induced by cyanobionts (symbiotic cyanobacteria). Here, we demonstrated that model plant-symbiotic cyanobacteria, Nostoc punctiforme capable protecting against programmed cell death (PCD) when in Arabidopsis thaliana suspension cultures. We also profiled early transcriptomic changes were response to conditioned medium (CM) from N. Interestingly, reduction PCD was preceded induction genes associated defence and immunity, most striking which number WRKY-family transcription factors. Down-regulated included those involved regulation growth differentiation. This work first show cyanobiont affect provides useful transcriptome resource for studying symbiotic cyanobacteria.