Deconvoluting ACS1 retrograde signaling networks that regulate leaf development

Signals originating within plastids modulate organelle differentiation by transcriptionally regulating nuclear-encoded genes. These retrograde signals are also integral regulators of plant development, including leaf morphology. The clb5 mutant displays severe leaf morphology defects due to Apocarotenoid Signal 1 (ACS1) accumulation in the developmentally arrested plastid. Transcriptomic analysis of clb5 validates ACS1 as a true retrograde signal impacting expression of hundreds of nuclear genes, including suppression of most genes encoding plastid ribosomal proteins. Examination of Arabidopsis mutant leaves and cotyledons; three replicates of six genotypes or stages were analyzed by RNA-seq.