AtC3H14, a direct target of MYB46, suppress cell elongation and involved in the secondary wall formation.

Recently, AtC3H14, a CCCH-type zinc finger protein, was identified as one of the direct targets of MYB46, which is known as a master regulator of secondary wall biosynthesis. AtC3H14 and their homologs (i.e., AtC3H15 and PtrC3H14-1 from Arabidopsis and poplar, respectively) are predominantly expressed in the secondary wall forming tissues. Transgenic Arabidopsis plants overexpressing AtC3H14 (i.e., 35S::AtC3H14 plants) produced dwarfing phenotypes. 35S::AtC3H14 plants developed phloem fibers earlier than wild-type and this phenotype was more pronounced in the roots. Interestingly, ectopic secondary wall thickenings were found in both stems and roots. These phenotypic consequences are successively reproduced from the 35S::AtC3H15 and 35S::PtrC3H14-1 plants. Whole transcriptome GeneChip analysis identified that the cell wall and extracellular-related genes are extremely over-represented in the stem tissues of 35S::AtC3H14 plants. These results suggest that AtC3H14 may act as a negative regulator of cell elongation with modification of cell wall reassembly and be involved in the secondary wall formation in Arabidopsis.

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Kim WC, Kim JY, Ko JH, Kang H, Kim J, Han KH