Auxin Inactivation and Its Relation to Leaf Drop Caused by the Fungus Omphalia Flavida

Steeves, Taylor A.

doi:10.1104/pp.29.1.11

Cited by 50 publications

(19 citation statements)

References 6 publications

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“…S4 and S7) (41,42,44). Of note, communication between events modulating auxin content in the blade with an effect on the petiole was observed more than 60 years ago (47).…”

Section: Discussionmentioning

confidence: 99%

Local auxin production underlies a spatially restricted neighbor-detection response inArabidopsis

Michaud

Fiorucci

Xenarios

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

153

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Competition for light triggers numerous developmental adaptations known as the "shade-avoidance syndrome" (SAS). Important molecular events underlying specific SAS responses have been identified. However, in natural environments light is often heterogeneous, and it is currently unknown how shading affecting part of a plant leads to local responses. To study this question, we analyzed upwards leaf movement (hyponasty), a rapid adaptation to neighbor proximity, in Arabidopsis. We show that manipulation of the light environment at the leaf tip triggers a hyponastic response that is restricted to the treated leaf. This response is mediated by auxin synthesized in the blade and transported to the petiole. Our results suggest that a strong auxin response in the vasculature of the treated leaf and auxin signaling in the epidermis mediate leaf elevation. Moreover, the analysis of an auxinsignaling mutant reveals signaling bifurcation in the control of petiole elongation versus hyponasty. Our work identifies a mechanism for a local shade response that may pertain to other plant adaptations to heterogeneous environments.neighbor detection | organ-specific response | hyponasty | auxin | PIF

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“…S4 and S7) (41,42,44). Of note, communication between events modulating auxin content in the blade with an effect on the petiole was observed more than 60 years ago (47).…”

Section: Discussionmentioning

confidence: 99%

Local auxin production underlies a spatially restricted neighbor-detection response inArabidopsis

Michaud

Fiorucci

Xenarios

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

153

View full text Add to dashboard Cite

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“…The suggestion has been made that the nucleic acid binds cations, while the protein moiety binds anions. LITERATURE CITED The plant growth hormone, indoleacetic acid (IAA), is known to be oxidatively inactivated by enzyme preparations from various plant sources (6,12,16,18,19). It has usually been assumed that the oxidation product is 3-indolealdehyde (16,19 ring; (c) The product apparently has a carbonyl group, since it forms an insoluble 2,4-dinitrophenylhydrazone (19).…”

Section: Discussionmentioning

confidence: 99%

On the Nature of the Enzymatically Catalyzed Oxidation Products of Indoleacetic Acid.

Manning

Galston²

1955

Plant Physiol.

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“…Auxin biosynthesis in seedlings occurs mostly in the cotyledons, and polar auxin transport to the hypocotyl subsequently induces elongation in low R/FR (12). Within a leaf, polar auxin transport also spatially relays signals (21) and is required for low R/FR-induced petiole elongation (18) and thus for shade avoidance (22,23).…”

mentioning

confidence: 99%

Neighbor detection at the leaf tip adaptively regulates upward leaf movement through spatial auxin dynamics

Pantazopoulou

Bongers

Küpers

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

140

221

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Vegetation stands have a heterogeneous distribution of light quality, including the red/far-red light ratio (R/FR) that informs plants about proximity of neighbors. Adequate responses to changes in R/FR are important for competitive success. How the detection and response to R/FR are spatially linked and how this spatial coordination between detection and response affects plant performance remains unresolved. We show in Arabidopsis thaliana and Brassica nigra that localized FR enrichment at the lamina tip induces upward leaf movement (hyponasty) from the petiole base. Using a combination of organ-level transcriptome analysis, molecular reporters, and physiology, we show that PIF-dependent spatial auxin dynamics are key to this remote response to localized FR enrichment. Using computational 3D modeling, we show that remote signaling of R/FR for hyponasty has an adaptive advantage over local signaling in the petiole, because it optimizes the timing of leaf movement in response to neighbors and prevents hyponasty caused by self-shading.leaf movement | auxin | phytochrome | functional-structural plant model | shade avoidance P lant canopies have pronounced gradients of light intensity between the top and bottom because leaves shade one another (1). As a consequence of the clustering of leaves, light intensities also vary horizontally. Because light drives photosynthesis, this variable light intensity creates selection pressure for plants to position their leaves for optimal light capture. Leaves do not absorb all wavelengths of the incoming light equally, and therefore light quality also differs vertically and horizontally in canopies (1-3) and even across the surface of individual leaves (4). Leaves preferentially absorb red (R) (λ = 600-700 nm) and blue (B) (λ = 400-500 nm) light for photosynthesis while reflecting most of the far-red (FR) (λ= 700-800 nm) light. This preference leads to a relative enrichment of FR light (low R/FR) in the local vicinity of leaves, a signal of neighbor proximity (5).Low R/FR is sensed by phytochrome photoreceptors, mainly phytochrome B (phyB), and induces upward leaf movement (hyponasty) through differential petiole growth and elongation of stems and petioles, thus bringing the leaves higher, toward the more illuminated parts of the canopy (6-8). Plants are modular organisms, and such shade-avoidance responses could thus be restricted to the specific modules that sense shade cues (9-11). Although spatial separation was shown recently for hypocotyl elongation in small Brassica rapa seedlings (12), only more established plants are large enough to experience light quality heterogeneity over the plant body. It is unknown whether responses to a low R/FR in relatively mature Arabidopsis plants act locally or integrate detection from different plant parts.A low R/FR inactivates phytochromes, leading to the accumulation of active PHYTOCHROME INTERACTING FACTOR (PIF) transcription factors, notably PIF4, PIF5, and PIF7, that trigger expression of growth-promoting genes (13), including auxin s...

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Auxin Inactivation and Its Relation to Leaf Drop Caused by the Fungus Omphalia Flavida

Cited by 50 publications

References 6 publications

Local auxin production underlies a spatially restricted neighbor-detection response inArabidopsis

Local auxin production underlies a spatially restricted neighbor-detection response inArabidopsis

On the Nature of the Enzymatically Catalyzed Oxidation Products of Indoleacetic Acid.

Neighbor detection at the leaf tip adaptively regulates upward leaf movement through spatial auxin dynamics

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