Plant-specific Histone Deacetylases HDT½ Regulate GIBBERELLIN 2-OXIDASE 2 Expression to Control Arabidopsis Root Meristem Cell Number

Huchen Li, Jesus Torres-Garcia, David Latrasse, Moussa Benhamed, Stefan Schilderink, Wenkun Zhou, Olga Kulikova, Heribert Hirt, Ton Bisseling

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


Root growth is modulated by environmental factors and depends on cell production in the root meristem (RM). New cells in the meristem are generated by stem cells and transit-amplifying cells, which together determine RM cell number. Transcription factors and chromatin-remodelling factors have been implicated in regulating the switch from stem cells to transit-amplifying cells. Here we show that two Arabidopsis thaliana paralogs encoding plant-specific histone deacetylases, HDT1 and HDT2, regulate a second switch from transit-amplifying cells to expanding cells. Knockdown of HDT½ (hdt1,2i) results in an earlier switch and causes a reduced RM cell number. Our data show that HDT½ negatively regulate the acetylation level of the C19-GIBBERELLIN 2-OXIDASE 2 (GA2ox2) locus and repress the expression of GA2ox2 in the RM and elongation zone. Overexpression of GA2ox2 in the RM phenocopies the hdt1,2i phenotype. Conversely, knockout of GA2ox2 partially rescues the root growth defect of hdt1,2i. These results suggest that by repressing the expression of GA2ox2, HDT½ likely fine-tune gibberellin metabolism and they are crucial for regulating the switch from cell division to expansion to determine RM cell number. We propose that HDT½ function as part of a mechanism that modulates root growth in response to environmental factors.
Original languageEnglish (US)
Pages (from-to)2183-2196
Number of pages14
JournalThe Plant Cell
Issue number9
StatePublished - Aug 31 2017

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research was supported by European Research Council (ERC-2011-AdG-294790) and China Scholarship Council (CSC). We thank Ben Scheres from Plant Developmental Biology, Wageningen University and Research Center for his critical reading of this article, and for the provision of Arabidopsis transgenic GFP reporter lines.


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