Overexpressed phytochrome C has similar photosensory specificity to phytochrome B but a distinctive capacity to enhance primary leaf expansion

Qin, Min; Kuhn, Robert M.; Moran, Sharon; Quail, Peter H.

doi:10.1046/j.1365-313x.1997.12051163.x

Cited by 53 publications

(34 citation statements)

References 50 publications

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“…Similar findings were observed in other BR biosynthetic mutants, including de-etiolated 2 (det2) and dwarf4 (dwf4) -both of which show shortened leaves (Altmann, 1998;Fujioka et al, 1997;Li and Chory, 1997;Azpiroz et al, 1998;Choe et al, 1998). Other factors that affect cell expansion, including auxins and light, have also been found to regulate leaf morphology (Timpte et al, 1992;Qin et al, 1997;Franklin et al, 2003;Kozuka et al, 2005) The different leaf morphologies observed in the various Arabidopsis ecotypes are likely to be determined by multiple factors. A genetic screen of leaf-shape mutants from 5770 M1 EMSmutagenized Arabidopsis plants generated 94 complementation groups that showed altered leaf morphology (Berna et al, 1999).…”

Section: Longifolia1 and Longifolia2 Two Homologous Genes Regulate supporting

confidence: 69%

LONGIFOLIA1andLONGIFOLIA2, two homologous genes,regulate longitudinal cell elongation inArabidopsis

Lee

Kim

Kim³

et al. 2006

Development

145

121

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Plants have diversified their leaf morphologies to adapt to diverse ecological niches. The molecular components responsible for regulating leaf morphology, however, have not been fully elucidated. By screening Arabidopsis activation-tagging lines, we identified a dominant mutant, which we designated longifolia1-1D (lng1-1D). lng1-1D plants were characterized by long petioles, narrow but extremely long leaf blades with serrated margins, elongated floral organs, and elongated siliques. The elongated leaves of the mutant were due to increased polar cell elongation rather than increased cell proliferation. Molecular characterization revealed that this phenotype was caused by overexpression of the novel gene LNG1, which was found to have a homolog, LNG2, in Arabidopsis. To further examine the role of the LNG genes, we characterized lng1 and lng2 loss-of-function mutant lines. In contrast to the elongated leaves of lng1-1D plants, the lng1 and lng2 mutants showed slightly decreased leaf length. Furthermore, the lng1-3 lng2-1 double mutant showed further decreased leaf length associated with less longitudinal polar cell elongation. The leaf widths in lng1-3 lng2-1 mutant plants were similar to those in wild type, implying that the role of LNG1 and LNG2 on polar cell elongation is similar to that of ROTUNDIFOLIA3 (ROT3). However, analysis of a lng1-3 lng2-1 rot3-1 triple mutant and of a lng1-1D rot3-1 double mutant indicated that LNG1 and LNG2 promote longitudinal cell elongation independently of ROT3. Taken together, these findings indicate that LNG1 and LNG2 are new components that regulate leaf morphology by positively promoting longitudinal polar cell elongation independently of ROT3 in Arabidopsis.

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Section: Longifolia1 and Longifolia2 Two Homologous Genes Regulate supporting

confidence: 69%

LONGIFOLIA1andLONGIFOLIA2, two homologous genes,regulate longitudinal cell elongation inArabidopsis

Lee

Kim

Kim³

et al. 2006

Development

145

121

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“…Based on the available data from higher order mutants (Halliday et al, 1994;Reed et al, 1994;Devlin et al, 1996Devlin et al, , 1998Devlin et al, , 1999Shalitin et al, 2002), it was inferred that phyC likely contributed marginally to photomorphogenesis. Studies with Arabidopsis phyC overexpressors showed a marginal hypocotyl phenotype in Rc and a possible role for phyC in primary leaf expansion (Qin et al, 1997). Very recently, Franklin and collaborators reported that a phyA phyB phyD phyE quadruple mutant still retains some weak responses to Rc, specifically in cotyledon development (Franklin et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…Visually, it was observed that this increase in petiole elongation correlated with a decrease in leaf area ( Figure 4C). A role for phyC in primary leaf expansion was proposed by Qin et al (1997) based on the observation that primary leaves in transgenic Arabidopsis plants overexpressing phyC were larger than those of the corresponding wild type.…”

Section: Phyc Mutants Exhibit Elongated Petioles and Larger Primary Lmentioning

confidence: 99%

Isolation and Characterization of phyC Mutants in Arabidopsis Reveals Complex Crosstalk between Phytochrome Signaling Pathways

et al. 2003

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Studies with mutants in four members of the five-membered Arabidopsis phytochrome (phy) family (phyA, phyB, phyD, and phyE) have revealed differential photosensory and/or physiological functions among them, but identification of a phyC mutant has proven elusive. We now report the isolation of multiple phyC mutant alleles using reverse-genetics strategies. Molecular analysis shows that these mutants have undetectable levels of phyC protein, suggesting that they are null for the photoreceptor. phyC mutant seedlings were indistinguishable from wild-type seedlings under constant far-red light (FRc), and phyC deficiency had no effect in the phyA mutant background under FRc, suggesting that phyC does not participate in the control of seedling deetiolation under FRc. However, when grown under constant red light (Rc), phyC seedlings exhibited a partial loss of sensitivity, observable as longer hypocotyls and smaller cotyledons than those seen in the wild type. Although less severe, this phenotype resembles the effect of phyB mutations on photoresponsiveness, indicating that both photoreceptors function in regulating seedling deetiolation in response to Rc. On the other hand, phyB phyC double mutants did not show any apparent decrease in sensitivity to Rc compared with phyB seedlings, indicating that the phyC mutation in the phyB-deficient background does not have an additive effect. These results suggest that phyB is necessary for phyC function. This functional dependence correlates with constitutively lower levels of phyC observed in the phyB mutant compared with the wild type, a decrease that seems to be regulated post-transcriptionally. phyC mutants flowered early when grown in short-day photoperiods, indicating that phyC plays a role in the perception of daylength. phyB phyC double mutant plants flowered similarly to phyB plants, indicating that in the phyB background, phyC deficiency does not further accelerate flowering. Under long-day photoperiods, phyA phyC double mutant plants flowered later than phyA plants, suggesting that phyC is able to promote flowering in the absence of phyA. Together, these results suggest that phyC is involved in photomorphogenesis throughout the life cycle of the plant, with a photosensory specificity similar to that of phyB/D/E and with a complex pattern of differential crosstalk with phyA and phyB in the photoregulation of multiple developmental processes.

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“…In contrast, high light intensity inhibits the elongation of the leaf petiole and promotes the expansion of the leaf blade. The shadeavoidance syndrome is under the control of signals in response to the red light perceived by phytochromes (phy A to E) in Arabidopsis (e.g., Devlin et al, 1996;Qin et al, 1997;Devlin et al, 1999;Franklin et al, 2003a;Franklin et al, 2003b). The differences between the sizes of the leaf petioles of plants grown under low light and high light conditions are attributable to the length of each cell in the petiole, while the differences between the sizes of the leaf blades under low light and high light conditions represent the sum of the number and sizes of cells in the leaf lamina .…”

Section: Environmental Adaptation and Adjustment: Photomorphogenesis mentioning

confidence: 99%

Leaf shape: genetic controls and environmental factors

Tsukaya¹

2005

Int. J. Dev. Biol.

254

194

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In recent years, many genes have been identified that are involved in the developmental processes of leaf morphogenesis. Here, I review the mechanisms of leaf shape control in a model plant, Arabidopsis thaliana, focusing on genes that fulfill special roles in leaf development. The lateral, two-dimensional expansion of leaf blades is highly dependent on the determination of the dorsoventrality of the primordia, a defining characteristic of leaves. Having a determinate fate is also a characteristic feature of leaves and is controlled by many factors. Lateral expansion is not only controlled by general regulators of cell cycling, but also by the multi-level regulation of meristematic activities, e.g., specific control of cell proliferation in the leaf-length direction, in leaf margins and in parenchymatous cells. In collaboration with the polarized control of leaf cell elongation, these redundant and specialized regulating systems for cell cycling in leaf lamina may realize the elegantly smooth, flat structure of leaves. The unified, flat shape of leaves is also dependent on the fine integration of cell proliferation and cell enlargement. Interestingly, while a decrease in the number of cells in leaf primordia can trigger a cell volume increase, an increase in the number of cells does not trigger a cell volume decrease. This phenomenon is termed «compensation» and suggests the existence of some systems for integration between cell cycling and cell enlargement in leaf primordia via cell-cell communication. The environmental adjustment of leaf expansion to light conditions and gravity is also summarized.

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Overexpressed phytochrome C has similar photosensory specificity to phytochrome B but a distinctive capacity to enhance primary leaf expansion

Cited by 53 publications

References 50 publications

LONGIFOLIA1andLONGIFOLIA2, two homologous genes,regulate longitudinal cell elongation inArabidopsis

LONGIFOLIA1andLONGIFOLIA2, two homologous genes,regulate longitudinal cell elongation inArabidopsis

Isolation and Characterization of phyC Mutants in Arabidopsis Reveals Complex Crosstalk between Phytochrome Signaling Pathways

Leaf shape: genetic controls and environmental factors

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