Induced deactivation of genes encoding chlorophyll biosynthesis enzymes disentangles tetrapyrrole-mediated retrograde signaling.

摘要: ABSTRACT In photosynthetic organisms, tetrapyrrole-mediated retrograde signals are proposed to contribute a balanced nuclear gene expression (NGE) in response metabolic activity chloroplasts. We followed an experimental short-term approach that allowed the assessment of modified NGE during first hours specifically enzymatic steps Mg branch tetrapyrrole biosynthesis, when pleiotropic effects other can be avoided. 24-h-induced silencing CHLH , CHLM and CHL27 encoding subunit chelatase, protoporphyrin methyltransferase monomethylester cyclase, respectively, deactivated rapidly led reduced corresponding enzymes altered porphyrin levels. But was not substantially altered. When these three genes were continuously inactivated for up 4 d, changes transcript levels determined. more than 24h results necrotic leaf lesions modulated oxidative stress-responsive photosynthesis-associated (PhANGs). The prolonged deactivation slightly elevated PhANGs tetrapyrrole-associated genes. These time-resolved studies indicate complex scenario contribution biosynthesis on mediated by 1 O 2 -induced signaling feedback-regulated ALA synthesis.