Shoot Apical Meristem Form and Function

Ha, Chan Man; Jun, Ji Hyung; Fletcher, Jennifer

doi:10.1016/s0070-2153(10)91004-1

Cited by 103 publications

(96 citation statements)

References 204 publications

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“…The increased size of SAMs in er erl1 erl2 is linked with raised expression of WUSCHEL (WUS) and SHOOT MER-ISTEMLESS (STM; Fig. 4A), key regulators of meristem development (Ha et al, 2010). At the same time, we observed decreased expression of ASYMMETRIC LEAVES1 (AS1; Fig.…”

Section: Erfs Are Critical For the Initiation Of Leaf Primordia And Tmentioning

confidence: 72%

ERECTA Family Genes Regulate Auxin Transport in the Shoot Apical Meristem and Forming Leaf Primordia

et al. 2013

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Leaves are produced postembryonically at the flanks of the shoot apical meristem. Their initiation is induced by a positive feedback loop between auxin and its transporter PIN-FORMED1 (PIN1). The expression and polarity of PIN1 in the shoot apical meristem is thought to be regulated primarily by auxin concentration and flow. The formation of an auxin maximum in the L1 layer of the meristem is the first sign of leaf initiation and is promptly followed by auxin flow into the inner tissues, formation of the midvein, and appearance of the primordium bulge. The ERECTA family genes (ERfs) encode leucine-rich repeat receptor-like kinases, and in Arabidopsis (Arabidopsis thaliana), this gene family consists of ERECTA (ER), ERECTA-LIKE1 (ERL1), and ERL2. Here, we show that ERfs regulate auxin transport during leaf initiation. The shoot apical meristem of the er erl1 erl2 triple mutant produces leaf primordia at a significantly reduced rate and with altered phyllotaxy. This phenotype is likely due to deficiencies in auxin transport in the shoot apex, as judged by altered expression of PIN1, the auxin reporter DR5rev::GFP, and the auxininducible genes MONOPTEROS, INDOLE-3-ACETIC ACID INDUCIBLE1 (IAA1), and IAA19. In er erl1 erl2, auxin presumably accumulates in the L1 layer of the meristem, unable to flow into the vasculature of a hypocotyl. Our data demonstrate that ERfs are essential for PIN1 expression in the forming midvein of future leaf primordia and in the vasculature of emerging leaves.

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Section: Erfs Are Critical For the Initiation Of Leaf Primordia And Tmentioning

confidence: 72%

ERECTA Family Genes Regulate Auxin Transport in the Shoot Apical Meristem and Forming Leaf Primordia

et al. 2013

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“…FON1 and FON2 are orthologs of Arabidopsis CLAVATA1 (CLV1) and CLV3 (Clark et al, 1997;Fletcher et al, 1999;Ha et al, 2010). Both the FON and CLV genes negatively regulate stem cell proliferation, and plants having defects in these genes show a stronger increase in carpel number than in stamen number.…”

Section: Discussionmentioning

confidence: 99%

Polar patterning of the spikelet is disrupted in the <i>two opposite lemma</i> mutant in rice

2016

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Angiosperms produce diverse flowers and the pattern of floral symmetry is a major factor for flower diversification. Bilaterally symmetric flowers have evolved multiple times in different angiosperm lineages from radially symmetric ancestors. Whereas most monocots produce radially symmetric flowers, grasses such as rice (Oryza sativa) and maize (Zea mays) generate bilaterally symmetric flowers and spikelets. In this paper, we focused on the two opposite lemma (tol) mutant, which displays a pleiotropic phenotype in the spikelet. Close morphological examination revealed that a typical spikelet phenotype of the tol mutant was principally based on the mirror image duplication of the lemma-side half of the spikelet. Other spikelet phenotypes can be explained as the derivation from the spikelet with this duplication. A polar pattern of organ formation along the lemma-palea axis was disrupted by this duplication. Accordingly, tol mutation seems to change the spikelet from bilateral symmetry (monosymmetry) to disymmetry. Thus, the tol mutant provides good genetic material to investigate the regulation of spikelet symmetry in rice.

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“…PZ cells further differentiate into lateral organ primordia on the meristem flanks (Irish and Sussex, 1992;Leyser and Furner, 1992). Proper, continuous growth of the plant thus requires longterm function of the SAM, itself depending on a coordinated balance between cell proliferation and differentiation (Laux, 2003;Ha et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…In Arabidopsis thaliana, SAM homeostasis is governed by a feedback loop signalling network involving the CLAVATA (CLV) and WUSCHEL (WUS) factors (Ha et al, 2010). The WUS homeobox transcription factor is both necessary and sufficient for stem cell specification (Laux et al, 1996;Mayer et al, 1998;Schoof et al, 2000;Lenhard et al, 2002;Gallois et al, 2004;Leibfried et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The Myb-domain protein ULTRAPETALA1 INTERACTING FACTOR 1 controls floral meristem activities in Arabidopsis

et al. 2016

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Higher plants continuously and iteratively produce new above-ground organs in the form of leaves, stems and flowers. These organs arise from shoot apical meristems whose homeostasis depends on coordination between self-renewal of stem cells and their differentiation into organ founder cells. This coordination is stringently controlled by the central transcription factor WUSCHEL (WUS), which is both necessary and sufficient for stem cell specification in Arabidopsis thaliana. ULTRAPETALA1 (ULT1) was previously identified as a plant-specific, negative regulator of WUS expression. However, molecular mechanisms underlying this regulation remain unknown. ULT1 protein contains a SAND putative DNA-binding domain and a B-box, previously proposed as a protein interaction domain in eukaryotes. Here, we characterise a novel partner of ULT1, named ULT1 INTERACTING FACTOR 1 (UIF1), which contains a Myb domain and an EAR motif. UIF1 and ULT1 function in the same pathway for regulation of organ number in the flower. Moreover, UIF1 displays DNA-binding activity and specifically binds to WUS regulatory elements. We thus provide genetic and molecular evidence that UIF1 and ULT1 work together in floral meristem homeostasis, probably by direct repression of WUS expression.

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Shoot Apical Meristem Form and Function

Cited by 103 publications

References 204 publications

ERECTA Family Genes Regulate Auxin Transport in the Shoot Apical Meristem and Forming Leaf Primordia

ERECTA Family Genes Regulate Auxin Transport in the Shoot Apical Meristem and Forming Leaf Primordia

Polar patterning of the spikelet is disrupted in the <i>two opposite lemma</i> mutant in rice

The Myb-domain protein ULTRAPETALA1 INTERACTING FACTOR 1 controls floral meristem activities in Arabidopsis

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