Retrograde signals reprogram plant chromatin allowing full expression of nuclear encoded photosynthesis genes

Retrograde signalling networks originating in the organelles dictate nuclear gene expression and are essential for control and regulation of cellular energy metabolism. We asked whether such plastid retrograde signals control gene expression by altering the chromatin state. An Arabidopsis thaliana single cell culture provided the required temporal resolution to map four histone marks during a process dependent on plastid signals, the establishment of photosynthetic function in response to light. Sequential and distinct epigenetic reprogramming events were revealed during the greening process, where an epigenetic activation through the histone acetylation H3K27ac was shown to be dependent on the plastid signal.