Local expression of expansin induces the entire process of leaf development and modifies leaf shape

Pien, Stéphane; Wyrzykowska, Joanna; McQueen‐Mason, Simon J.; Smart, Cheryl C.; Fleming, Andrew J.

doi:10.1073/pnas.191380498

Cited by 317 publications

(258 citation statements)

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“…In general, it seems likely that both processes of cell production and expansion are sensitive to the supply of CO 2 , but their influence on leaf size and shape varies depending on species and other environmental conditions. Pien et al (2001) have suggested a link between carbon supply, cell wall loosening, and leaf cell expansion in the alteration of leaf shape, and such a mechanism could be operating here. Cell expansion was clearly altered at one time by elevated [CO 2 ] for young leaves, but there was no evidence that this effect persisted and was responsible for altered leaf shape.…”

Section: Discussionmentioning

confidence: 84%

Spatial and Temporal Effects of Free-Air CO2Enrichment (POPFACE) on Leaf Growth, Cell Expansion, and Cell Production in a Closed Canopy of Poplar

et al. 2003

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Leaf expansion in the fast-growing tree, Populus ϫ euramericana was stimulated by elevated [CO 2 ] in a closed-canopy forest plantation, exposed using a free air CO 2 enrichment technique enabling long-term experimentation in field conditions. The effects of elevated [CO 2 ] over time were characterized and related to the leaf plastochron index (LPI), and showed that leaf expansion was stimulated at very early (LPI, 0-3) and late (LPI, 6-8) stages in development. Early and late effects of elevated [CO 2 ] were largely the result of increased cell expansion and increased cell production, respectively. Spatial effects of elevated [CO 2 ] were also marked and increased final leaf size resulted from an effect on leaf area, but not leaf length, demonstrating changed leaf shape in response to [CO 2 ]. Leaves exhibited a basipetal gradient of leaf development, investigated by defining seven interveinal areas, with growth ceasing first at the leaf tip. Interestingly, and in contrast to other reports, no spatial differences in epidermal cell size were apparent across the lamina, whereas a clear basipetal gradient in cell production rate was found. These data suggest that the rate and timing of cell production was more important in determining leaf shape, given the constant cell size across the leaf lamina. The effect of elevated [CO 2 ] imposed on this developmental gradient suggested that leaf cell production continued longer in elevated [CO 2 ] and that basal increases in cell production rate were also more important than altered cell expansion for increased final leaf size and altered leaf shape in elevated [CO 2 ].Given the importance of forests for global bioproductivity, the consequences of increased atmospheric [CO 2 ] for the global carbon cycle are potentially extremely large (Malhi et al., 1999). Despite this, there are still relatively few large-scale, long-term experiments from which predictions about likely forest responses can be made. Few studies have been completed where trees are allowed to develop to canopy closure and where a "stable" response to [CO 2 ] is likely. Determining the response of leaf area development to elevated [CO 2 ] is important. It is still unknown whether forests of the future will maintain a higher leaf area index (LAI), as implied from smalltree studies (Ceulemans et al., 1997) or whether the long-term (decades) responses will be reduced allocation to foliage and lower LAI, as suggested by some modeling approaches (Medlyn and Dewar, 1996) or involve acclimation to limited nitrogen (Oren et al., 2001).Leaf growth is often stimulated in short-term response to elevated [CO 2 ] (Taylor et al., 1994;Pritchard et al., 1999), and both leaf cell expansion and cell production are sensitive to [CO 2 ] (Taylor et al., 1994). It is likely that these processes respond to additional carbohydrate from photosynthesis and, as such, altered atmospheric [CO 2 ] provides a critical insight into how carbon regulates plant development and growth (Masle, 2000). The importance of leaf develo...

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Section: Discussionmentioning

confidence: 84%

Spatial and Temporal Effects of Free-Air CO2Enrichment (POPFACE) on Leaf Growth, Cell Expansion, and Cell Production in a Closed Canopy of Poplar

et al. 2003

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“…Local exogenous applications of expansins to the SAM could induce a primordia-like structure [18]. Later modification of the technique involved local and inducible expression of an endogenous expansin in the SAM, which led to the initiation and development of normal leaves [19]. The difference in leaf morphology between these two experiments was attributed to limited penetration and thus restricted accumulation of the expansin in the L1 in the former, while expansin was expressed in all layers in the latter [19].…”

Section: The Epidermis As a Barrier -A Biophysical Viewmentioning

confidence: 99%

“…Later modification of the technique involved local and inducible expression of an endogenous expansin in the SAM, which led to the initiation and development of normal leaves [19]. The difference in leaf morphology between these two experiments was attributed to limited penetration and thus restricted accumulation of the expansin in the L1 in the former, while expansin was expressed in all layers in the latter [19]. In a different experiment, spatio-temporal examination of the L1 in the SAM by means of laserbased ablation techniques revealed that it was essential for organ formation [20], since leaf primordia were not formed at the ablated site.…”

Section: The Epidermis As a Barrier -A Biophysical Viewmentioning

confidence: 99%

Growth coordination and the shoot epidermis

Savaldi-Goldstein

Chory

2008

Current Opinion in Plant Biology

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SummaryCell-cell communication is essential for growth and development of multicellular organisms. In higher plants, the shoot organs are derived from three clonally distinct cell layers present in the meristem. The role of the outermost L1 cell-layer and its derived epidermis in coordinating growth of the inner cell-layers has long been debated. This question has been revisited recently using molecular tools to manipulate cell cycle progression or cell expansion, specifically in the epidermis. These studies conclude that cells in the epidermis both promote and restrict growth of the entire shoot by sending growth signals-either physical or chemical-to the inner layers.

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“…Inducible systems include those regulated by tetracycline, steroids, insecticides, ethanol and copper [52]. Precise control of transcription is achievable using inducible promoters in combination with microinduction, where the chemical inducer is embedded in a paste and applied under the microscope [53]. Microinduction has been used in combination with a tetracycline-inducible promoter driving expression of expansin and phragmoplastin, enabling control of gene expression in small areas within the meristem [53,54].…”

Section: Inducible Promotersmentioning

confidence: 99%

“…Precise control of transcription is achievable using inducible promoters in combination with microinduction, where the chemical inducer is embedded in a paste and applied under the microscope [53]. Microinduction has been used in combination with a tetracycline-inducible promoter driving expression of expansin and phragmoplastin, enabling control of gene expression in small areas within the meristem [53,54]. Among the inducible systems, the alcohol-inducible switch -based on components of the alc regulon, including AlcR transcriptional activator and alcA promoter of Aspergillus nidulans [55] -has been considered as one of the most promising in a wide range of model and crop plants.…”

Section: Inducible Promotersmentioning

confidence: 99%