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Gibberellin signaling in the endodermis controls Arabidopsis root meristem size

(2009) Current Biology. 19(14). p.1194-1199
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Abstract
Plant growth is driven by cell proliferation and elongation [1]. The hormone gibberellin (GA) regulates Arabidopsis root growth [2-5] by controlling cell elongation [6], but it is currently unknown whether GA also controls root cell proliferation. Here we show that GA biosynthetic mutants are unable to increase their cell production rate and meristem size after germination. GA signals the degradation of the DELLA growth repressor proteins [7-12] GAI and RGA, promoting root cell production. Targeting the expression of gai (a non-GA-degradable mutant form of GAI) in the root meristem disrupts cell proliferation. Moreover, expressing gai in dividing endodermal cells was sufficient to block root meristem enlargement. We report a novel function for GA regulating cell proliferation where this signal acts by removing DELLA in a subset of, rather than all, meristem cells. We suggest that the GA-regulated rate of expansion of dividing endodermal cells dictates the equivalent rate in other root tissues. Cells must double in size prior to dividing but cannot do so independently, because they are physically restrained by adjacent tissues with which they share cell walls. Our study highlights the importance of probing regulatory mechanisms linking molecular- and cellular-scale processes with tissue and organ growth responses.
Keywords
GAI, GROWTH, RGA, BIOSYNTHESIS, RECOGNITION, DEGRADATION, ARABIDOPSIS THALIANA, CELL-DIFFERENTIATION, RECEPTOR GID1, DELLA PROTEIN

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Chicago
Ubeda-Tomás, Susana, Fernán Federici, Ilda Casimiro, Gerrit Beemster, Rishikesh Bhalerao, Ranjan Swarup, Peter Doerner, Jim Haseloff, and Malcolm Bennett. 2009. “Gibberellin Signaling in the Endodermis Controls Arabidopsis Root Meristem Size.” Current Biology 19 (14): 1194–1199.
APA
Ubeda-Tomás, S., Federici, F., Casimiro, I., Beemster, G., Bhalerao, R., Swarup, R., Doerner, P., et al. (2009). Gibberellin signaling in the endodermis controls Arabidopsis root meristem size. Current Biology, 19(14), 1194–1199.
Vancouver
1.
Ubeda-Tomás S, Federici F, Casimiro I, Beemster G, Bhalerao R, Swarup R, et al. Gibberellin signaling in the endodermis controls Arabidopsis root meristem size. Current Biology. 2009;19(14):1194–9.
MLA
Ubeda-Tomás, Susana, Fernán Federici, Ilda Casimiro, et al. “Gibberellin Signaling in the Endodermis Controls Arabidopsis Root Meristem Size.” Current Biology 19.14 (2009): 1194–1199. Print.
@article{749066,
  abstract     = {Plant growth is driven by cell proliferation and elongation [1]. The hormone gibberellin (GA) regulates Arabidopsis root growth [2-5] by controlling cell elongation [6], but it is currently unknown whether GA also controls root cell proliferation. Here we show that GA biosynthetic mutants are unable to increase their cell production rate and meristem size after germination. GA signals the degradation of the DELLA growth repressor proteins [7-12] GAI and RGA, promoting root cell production. Targeting the expression of gai (a non-GA-degradable mutant form of GAI) in the root meristem disrupts cell proliferation. Moreover, expressing gai in dividing endodermal cells was sufficient to block root meristem enlargement. We report a novel function for GA regulating cell proliferation where this signal acts by removing DELLA in a subset of, rather than all, meristem cells. We suggest that the GA-regulated rate of expansion of dividing endodermal cells dictates the equivalent rate in other root tissues. Cells must double in size prior to dividing but cannot do so independently, because they are physically restrained by adjacent tissues with which they share cell walls. Our study highlights the importance of probing regulatory mechanisms linking molecular- and cellular-scale processes with tissue and organ growth responses.},
  author       = {Ubeda-Tom{\'a}s, Susana and Federici, Fern{\'a}n and Casimiro, Ilda and Beemster, Gerrit and Bhalerao, Rishikesh and Swarup, Ranjan and Doerner, Peter and Haseloff, Jim and Bennett, Malcolm},
  issn         = {0960-9822},
  journal      = {Current Biology},
  keyword      = {GAI,GROWTH,RGA,BIOSYNTHESIS,RECOGNITION,DEGRADATION,ARABIDOPSIS THALIANA,CELL-DIFFERENTIATION,RECEPTOR GID1,DELLA PROTEIN},
  language     = {eng},
  number       = {14},
  pages        = {1194--1199},
  title        = {Gibberellin signaling in the endodermis controls Arabidopsis root meristem size},
  url          = {http://dx.doi.org/10.1016/j.cub.2009.06.023},
  volume       = {19},
  year         = {2009},
}

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