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CCR1, an enzyme required for lignin biosynthesis in Arabidopsis, mediates cell proliferation exit for leaf development
Author(s) -
Xue Jingshi,
Luo Dexian,
Xu Deyang,
Zeng Minhuan,
Cui Xiaofeng,
Li Laigeng,
Huang Hai
Publication year - 2015
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12902
Subject(s) - arabidopsis , cell growth , mutant , ferulic acid , lignin , microbiology and biotechnology , biochemistry , chemistry , caffeic acid , biology , antioxidant , botany , gene
Summary After initiation, leaves first undergo rapid cell proliferation. During subsequent development, leaf cells gradually exit the proliferation phase and enter the expansion stage, following a basipetally ordered pattern starting at the leaf tip. The molecular mechanism directing this pattern of leaf development is as yet poorly understood. By genetic screening and characterization of Arabidopsis mutants defective in exit from cell proliferation, we show that the product of the CINNAMOYL CoA REDUCTASE ( CCR 1 ) gene, which is required for lignin biosynthesis, participates in the process of cell proliferation exit in leaves. CCR 1 is expressed basipetally in the leaf, and ccr1 mutants exhibited multiple abnormalities, including increased cell proliferation. The ccr1 phenotypes are not due to the reduced lignin content, but instead are due to the dramatically increased level of ferulic acid (FeA), an intermediate in lignin biosynthesis. FeA is known to have antioxidant activity, and the levels of reactive oxygen species ( ROS ) in ccr1 were markedly reduced. We also characterized another double mutant in CAFFEIC ACID O ‐ METHYLTRANSFERASE ( comt ) and CAFFEOYL CoA 3 ‐ O ‐ METHYLTRANSFERASE ( ccoaomt ), in which the FeA level was dramatically reduced. Cell proliferation in comt ccoaomt leaves was decreased, accompanied by elevated ROS levels, and the mutant phenotypes were partially rescued by treatment with FeA or another antioxidant ( N ‐acetyl‐ l ‐cysteine). Taken together, our results suggest that CCR 1, FeA and ROS coordinate cell proliferation exit in normal leaf development.