Abstract
Heme production lies at the branchpoint of the tetrapyrrole biosynthetic pathway where protoporphyrin IX is catalyzed by ferrochelatases. Arabidopsis contains two ferrochelatase genes, FC1 and FC2, the latter has characteristic C-terminal LHC motif. In this study, we characterized Arabidopsis T-DNA insertion mutants of fc1 and fc2. fc2 in which T-DNA is inserted between exons 6 and 7 showed a reduced expression of FC2 and have a pale green to yellowish phenotype. Growth is also highly impaired in this mutant lagging in both size and root length. fc1, on the other hand, had an insert in the promoter region and also showing a reduced expression level amidst having the wild-type phenotype in both color and size. Surprisingly, heme levels in both mutants were almost unchanged when evaluated by fresh weight level suggesting that the level of endogenous heme is highly maintained even in the absence of one of the ferrochelatase isoforms.
