The Diverse Roles of Auxin in Regulating Leaf Development

Leaves, the primary plant organs that function in photosynthesis and respiration, have highly organized, flat structures that vary within and among species. In recent years, it has become evident that auxin plays central roles in leaf development, including leaf initiation, blade formation, and compound leaf patterning. In this review, we discuss how auxin maxima form to define leaf primordium formation. We summarize recent progress in understanding of how spatial auxin signaling promotes leaf blade formation. Finally, we discuss how spatial auxin transport and signaling regulate the patterning of compound leaves and leaf serration.

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The rotated-lamina syndrome. III. Cases in Begonia, Corylus, Magnolia, Pellionia, Prunus, and Tilia

Canadian Journal of Botany ◽

10.1139/b93-025 ◽

1993 ◽

Vol 71 (2) ◽

pp. 229-247 ◽

Cited By ~ 10

Author(s):

W. A. Charlton

Keyword(s):

Leaf Development ◽

Leaf Blade ◽

Leaf Primordia ◽

Leaf Primordium ◽

Normal Leaf ◽

Normal Orientation ◽

Lateral Shoots ◽

Asymmetric Growth ◽

Prunus Laurocerasus

The rotated-lamina syndrome occurs in all adult shoots of Tilia × europaea, and in lateral shoots of Corylus spp. and Prunus laurocerasus. Corylus and Prunus also have orthotropic radially symmetrical shoots that have normal leaf orientation. Development of the syndrome in leaf primordia in Tilia and Corylus is similar to that previously described in Ulmus, i.e., the leaf primordium is initially asymmetrical so that the leaf blade component of the primordium arises facing only obliquely towards the shoot apex, and further asymmetrical outgrowth of the leaf buttress brings the leaf blade region into the rotated position. Leaves of Begonia foliosa and the ventral leaves of (anisophyllous) Pellionia pulchra arise from initially symmetrical primordia, and lamina rotation occurs by asymmetric growth at the base of the leaf blade region. The process is similar to that in the woody examples but occurs at a proportionately later stage of leaf development. Development of the syndrome in Prunis laurocerasus and Magnolia × soulangeana differs considerably. Primordia are slightly asymmetrical but have normal dorsiventrality at first, but when the lamina arises the two edges of the leaf blade grow towards the same (upper) side of the bud, and this is responsible for most of the appearance of rotation. In general the upper stipule is initially larger than the lower and arises much earlier in Corylus and Tilia. Leaves that have normal orientation in Corylus and Prunus develop from quite symmetrical primordia, but those of Cotylus may show some asymmetry of stipule development. Shoots of all cases can be considered to show heteroblastic growth, and the early part of the heteroblastic sequence is prolonged in the orthotropic shoots with normally oriented leaves in Corylus and Prunus. The morphological and morphogenetic significance of the rotated-lamina syndrome is discussed. Key words: Begonia, Corylus, Magnolia, Pellionia, Prunus, Tilia, leaf, development, dorsiventrality, lamina rotation.

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Gravity sensing and signal conversion in plant gravitropism

Journal of Experimental Botany ◽

10.1093/jxb/erz158 ◽

2019 ◽

Vol 70 (14) ◽

pp. 3495-3506 ◽

Cited By ~ 16

Author(s):

Moritaka Nakamura ◽

Takeshi Nishimura ◽

Miyo Terao Morita

Keyword(s):

Recent Progress ◽

Auxin Transport ◽

High Density ◽

Regulatory Mechanisms ◽

Plant Organs ◽

Set Point ◽

Signal Conversion ◽

Growth Orientation ◽

Plant Organ ◽

Physical Signal

AbstractPlant organs control their growth orientation in response to gravity. Within gravity-sensing cells, the input (gravity sensing) and signal conversion (gravity signalling) progress sequentially. The cells contain a number of high-density, starch-accumulating amyloplasts, which sense gravity when they reposition themselves by sedimentation to the bottom of the cell when the plant organ is re-orientated. This triggers the next step of gravity signalling, when the physical signal generated by the sedimentation of the amyloplasts is converted into a biochemical signal, which redirects auxin transport towards the lower flank of the plant organ. This review focuses on recent advances in our knowledge of the regulatory mechanisms that underlie amyloplast sedimentation and the system by which this is perceived, and on recent progress in characterising the factors that play significant roles in gravity signalling by which the sedimentation is linked to the regulation of directional auxin transport. Finally, we discuss the contribution of gravity signalling factors to the mechanisms that control the gravitropic set-point angle.

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Phototropin-mediated perception of light direction in Arabidopsis leaves regulates blade flattening

10.1101/2021.05.25.445665 ◽

2021 ◽

Author(s):

Christian Fankhauser ◽

Martina Legris ◽

Bogna Maria Szarzynska-Erden ◽

Martine Trevisan ◽

Laure Allenbach Petrolati

Keyword(s):

Blue Light ◽

Leaf Development ◽

Leaf Blade ◽

Light Response ◽

Auxin Signaling ◽

Kinase Substrate ◽

Key Aspects ◽

Light Capture ◽

Signaling Components

One conserved feature among angiosperms is the development of flat thin leaves. This developmental pattern optimizes light capture and gas exchange for photosynthesis. The blue light receptors phototropins are required for leaf flattening, with the null phot1phot2 mutant showing downwards curled leaves in Arabidopsis. However, key aspects of their function in leaf development remain unknown. Here, we performed a detailed spatiotemporal characterization of phototropin function in Arabidopsis leaves. We found that phototropins perceive light direction in the leaf blade, and similar to their role in hypocotyls they control the spatial pattern of auxin signaling possibly modulating auxin transport, to ultimately regulate cell expansion. Phototropin signaling components in the leaf partially differ from hypocotyls. Moreover, the light response on the upper (adaxial) and lower (abaxial) sides of the leaf blade suggest a partially distinct requirement of phototropin signaling components on each side. In particular, NON PHOTOTROPIC HYPOCOTYL 3 (NPH3) showed an adaxial-specific function. In addition, we show a prominent role of PHYTOCHROME KINASE SUBSTRATE 3 (PKS3) in leaf flattening. Among the auxin transporters tested, PINs and AUX/LAX influence the response most prominently. Overall, our results show that directional blue light perception by the phototropins is a key aspect of leaf development, integrating endogenous and exogenous signals.

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Membrane Sterol Composition in Arabidopsis thaliana Affects Root Elongation via Auxin Biosynthesis

International Journal of Molecular Sciences ◽

10.3390/ijms22010437 ◽

2021 ◽

Vol 22 (1) ◽

pp. 437

Author(s):

Meng Wang ◽

Panpan Li ◽

Yao Ma ◽

Xiang Nie ◽

Markus Grebe ◽

...

Keyword(s):

Root Elongation ◽

Auxin Transport ◽

Sterol Composition ◽

Polar Auxin Transport ◽

Sterol Biosynthesis ◽

Auxin Biosynthesis ◽

Root Tip ◽

Auxin Signaling ◽

Auxin Response ◽

Short Root

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (β-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.

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Maize LAZY1 Mediates Shoot Gravitropism and Inflorescence Development through Regulating Auxin Transport, Auxin Signaling, and Light Response

PLANT PHYSIOLOGY ◽

10.1104/pp.113.227314 ◽

2013 ◽

Vol 163 (3) ◽

pp. 1306-1322 ◽

Cited By ~ 55

Author(s):

Zhaobin Dong ◽

Chuan Jiang ◽

Xiaoyang Chen ◽

Tao Zhang ◽

Lian Ding ◽

...

Keyword(s):

Auxin Transport ◽

Light Response ◽

Auxin Signaling ◽

Inflorescence Development ◽

Shoot Gravitropism

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A crispa null mutant facilitates identification of a crispa-like pseudogene in pea

Functional Plant Biology ◽

10.1071/fp06090 ◽

2006 ◽

Vol 33 (8) ◽

pp. 757 ◽

Cited By ~ 3

Author(s):

Frank Sainsbury ◽

Alexander D. Tattersall ◽

Michael J. Ambrose ◽

Lynda Turner ◽

T. H. Noel Ellis ◽

...

Keyword(s):

Leaf Development ◽

Leaf Blade ◽

Deletion Mutant ◽

Sequence Data ◽

Null Mutation ◽

Legume Species ◽

Null Mutant ◽

Nucleotide Sequence Data ◽

Pisum Sativum L ◽

Redundant Gene

The genomes of several legume species contain two Phantastica-like genes. Previous studies on leaf development have found that Phantastica confers leaf blade adaxial identity in plant species with simple leaves and leaflet adaxial identity in pea (Pisum sativum L.), a legume with compound leaves. Previous characterisation of the phantastica mutant of pea, crispa, showed it had radialised leaflets, but stipules were not radialised. This suggested either that mutation of a second redundant gene was required for radialisation of stipules, or, that a null mutation was required. Previously characterised crispa mutants may not have exhibited radialised stipules because they were weak alleles. In this work we show that pea has a second Phantastica-like gene, which lies on a different chromosome to Crispa. The second gene was found to be a pseudogene in several genotypes of pea, therefore it would not have a role in conferring stipule adaxial identity. A new deletion mutant, crispa-4 was identified. The mutant has radialised stipules and leaflets, showing that Crispa confers adaxial identity on both these organs in pea. The nucleotide sequence data reported here are in the EMBL and GenBank Nucleotide Databases under the accession numbers DQ486060 (JI 2822), DQ486061 (JI 15), DQ486062 (JI 281) and DQ486063 (JI 399).

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The rotated-lamina syndrome. I. Ulmaceae

Canadian Journal of Botany ◽

10.1139/b93-023 ◽

1993 ◽

Vol 71 (2) ◽

pp. 211-221 ◽

Cited By ~ 12

Author(s):

W. A. Charlton

Keyword(s):

Leaf Blade ◽

Early Stage ◽

Leaf Primordia ◽

Leaf Primordium ◽

Foliage Leaf ◽

Normal Orientation ◽

Ulmus Glabra ◽

Young Leaves ◽

Final Orientation ◽

Zelkova Serrata

In a number of plants, mostly woody, the components of the buds are arranged so that the laminae of the young leaves all face towards the same (upper) side of the bud, rather than towards the bud apex; in axillary buds they usually face towards the parent axis. This situation has been known for many years. For convenience, the general case is here called the rotated-lamina syndrome. There have been very few developmental investigations of how the laminae attain their unusual orientation, and these have come to different conclusions about cases in the Ulmaceae. This paper reports a detailed investigation of the syndrome in Ulmus glabra and Zelkova serrata, with comparative observations on other Ulmaceae, including cases in Celtis that do not exhibit the syndrome. The syndrome arises by different means in Ulmus and Zelkova. In Ulmus the leaf primordium is asymmetrical from the outset, the leaf blade region is obliquely dorsiventral from an early stage, and further asymmetrical growth of the leaf buttress rotates the whole leaf blade region into its final orientation as it develops. Individual shoots show heteroblastic development in progressing from bud scale to foliage leaf initiation, in increasing accentuation of the rotated-lamina syndrome, and in an increasing degree of dorsiventrality. In Zelkova, as previously described, the leaf blade region appears first as a radially symmetrical upgrowth, and it acquires dorsiventral symmetry directly in the rotated position. In Celtis spp. the lamina arises in a quite normal orientation, but reorients as it emerges from the bud. The leaf primordia of all species studied show asymmetry in other aspects, particularly in respect of stipule development, and these seem to be general features of the organisation of dorsiventral shoots. Key words: Ulmus, Zelkova, Celtis, leaf, development, dorsiventrality, lamina rotation.

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Leaf development in eight related grasses

The Journal of Agricultural Science ◽

10.1017/s0021859600067757 ◽

1994 ◽

Vol 123 (1) ◽

pp. 41-46 ◽

Cited By ~ 3

Author(s):

Y. Gao ◽

D. Wilman

Keyword(s):

Perennial Ryegrass ◽

Tall Fescue ◽

Leaf Development ◽

Festuca Arundinacea ◽

Leaf Blade ◽

Leaf Sheath ◽

Leaf Expansion ◽

Italian Ryegrass ◽

Meadow Fescue ◽

Rate Of Increase

SummaryLeaf development was studied in eight related grasses, grown in field swards cut at 5-week intervals, during the year of sowing and the subsequent year (1989 and 1990). The rate of leaf expansion was in the order Westerwolds ryegrass > Italian ryegrass (Lolium multiflorum), Italian ryegrass × meadow fescue > hybrid ryegrass > perennial ryegrass × meadow fescue, meadow fescue (Festuca pratensis), tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne). The order of grasses was similar, but not identical, for rate of leaf appearance, rate of leaf extension, weight of leaf blade emerging per shoot per week and rate of increase in length of exposed leaf sheath, and the order was approximately the reverse for weight per unit area of emerging leaf blade. The area per leaf blade increased greatly between May and October of the year of sowing, particularly in Westerwolds, Italian and hybrid ryegrasses and Italian ryegrass × meadow fescue. Area per leaf blade in tall fescue increased greatly between May and July of the year of sowing and May–July of the subsequent year. Rate of leaf expansion in meadow fescue was much higher in May of the year after sowing than in the previous May.

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Morphogenesis of the compound leaf in three genotypes of the pea, Pisum sativum

Canadian Journal of Botany ◽

10.1139/b86-175 ◽

1986 ◽

Vol 64 (6) ◽

pp. 1268-1276 ◽

Cited By ~ 25

Author(s):

K. S. Gould ◽

Elizabeth G. Cutter ◽

J. P. W. Young

Keyword(s):

Pisum Sativum ◽

Leaf Development ◽

Culture System ◽

Algebraic Model ◽

Leaf Primordium ◽

Axillary Shoots ◽

Compound Leaf ◽

Pisum Sativum L ◽

Leaflet Anatomy

Leaf anatomy, ontogeny, and morphology were described and compared in a pea line (Pisum sativum L.) with conventional leaves and in isogenic lines carrying the mutations af (afila) or tl (tendril-less or acacia). The anatomy of stem, petiole, and rachis is not modified by these mutations. The tendrils, which in af replace leaflets, have normal tendril anatomy, and the terminal leaflets of the tl form have normal leaflet anatomy. The shoot apical dome has the same size and shape in the three genotypes, as does the leaf primordium up to the stage of initiation of the first laterals. The mature morphology of leaves varies with node of insertion. Some leaves, especially at nodes 3 and 4, have structures that are not typical of their genotype. An in vitro culture system is described for axillary shoots. Such shoots recapitulate most of the foliar features of seedling plants, but leaf morphology is on average more complex, and aberrant structures are more frequent. All these observations are discussed in relation to Young's algebraic model for compound leaf development.

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Influence of Light of Different Spectral Compositions on the Growth, Photosynthesis, and Expression of Light-Dependent Genes of Scots Pine Seedlings

Cells ◽

10.3390/cells10123284 ◽

2021 ◽

Vol 10 (12) ◽

pp. 3284

Author(s):

Pavel Pashkovskiy ◽

Vladimir D. Kreslavski ◽

Yury Ivanov ◽

Alexandra Ivanova ◽

Alexander Kartashov ◽

...

Keyword(s):

Red Light ◽

Spectral Composition ◽

Fluorescent Light ◽

Auxin Signaling ◽

Gene Encoding ◽

Chl A ◽

Expression Of Genes ◽

Dependent Change ◽

The Difference ◽

Photosynthesis And Respiration

Varying the spectral composition of light is one of the ways to accelerate the growth of conifers under artificial conditions for the development of technologies and to obtain sustainable seedlings required to preserve the existing areas of forests. We studied the influence of light of different quality on the growth, gas exchange, fluorescence indices of Chl a, and expression of key light-dependent genes of Pinus sylvestris L. seedlings. It was shown that in plants growing under red light (RL), the biomass of needles and root system increased by more than two and three times, respectively, compared with those of the white fluorescent light (WFL) control. At the same time, the rates of photosynthesis and respiration in RL and blue light (BL) plants were lower than those of blue red light (BRL) plants, and the difference between the rates of photosynthesis and respiration, which characterizes the carbon balance, was maximum under RL. RL influenced the number of xylem cells, activated the expression of genes involved in the transduction of cytokinin (Histidine-containing phosphotransfer 1, HPT1, Type-A Response Regulators, RR-A) and auxin (Auxin-induced protein 1, Aux/IAA) signals, and reduced the expression of the gene encoding the transcription factor phytochrome-interacting factor 3 (PIF3). It was suggested that RL-induced activation of key genes of cytokinin and auxin signaling might indicate a phytochrome-dependent change in cytokinins and auxins activity.

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