Studies of Cytokinin Action and Metabolism Using Tobacco Plants Expressing either the ipt or the GUS Gene Controlled by a Chalcone Synthase Promoter. I. Developmental Features of the Transgenic Plants

1997 ◽  
Vol 24 (5) ◽  
pp. 661 ◽  
Author(s):  
Jian Wang ◽  
D. S. Letham ◽  
Edwina Cornish ◽  
K. R. Stevenson
Keyword(s):  
Plant Development ◽  
Chalcone Synthase ◽  
Leaf Shape ◽  
Primary Root ◽  
Diffusion Resistance ◽  
Endogenous Cytokinin ◽  
Ipt Gene ◽  
Node Number ◽  
Transformed Plants ◽  
Developmental Features

A chimaeric cytokinin biosynthetic gene was constructed by placing the coding region of the bacterial ipt gene under the control of a chalcone synthase (chs) promoter (PCHS) from Antirrhinum majus. The PCHS-ipt gene was transferred to tobacco (Nicotiana tabacum L.). To provide control plants for studies of the effect of expression of this gene on plant development, a PCHS β-glucuronidase gene fusion was also introduced into tobacco. Expression of the PCHS-ipt gene caused release of axillary buds, inhibition of root development, retardation of leaf senescence, elevation of chlorophyll levels, delay in onset of flowering and retardation of flower development. These effects, which were quantified in PCHS- ipt plants, have previously been associated with expression of ipt genes controlled by heat shock or other promoters. Additional effects of ipt gene expression characterised in PCHS-ipt plants included growth of leafy shoots from the primary root, change in leaf shape with the production of broader and larger leaves, induction of expansion of excised leaf discs and development of leaves with an enlarged midrib and enlarged veins. A particularly striking effect of the expression of the PCHS-ipt gene was development of thicker stems due mainly to increase of pith tissue caused by an enhancement of both cell division and cell enlargement. Node number per primary stem was also increased. Endogenous cytokinin and applied auxin interacted antagonistically to affect both root and stem development in plants cultured in vitro. The leaves of PCHS -ipt transformed plants exhibited increased transpiration rates and reduced diffusion resistance associated with increased number of stomata and modified stomatal dimensions. The above changes, which were associated with elevated endogenous cytokinin levels, are discussed in relation to previous studies with ipt gene transformed plants and to some aspects of normal plant development.

Studies of Cytokinin Action and Metabolism Using Tobacco Plants Expressing either the ipt or the GUS Gene Controlled by a Chalcone Synthase Promoter. IIipt and GUS Gene Expression, Cytokinin Levels and Metabolism

1997 ◽  
Vol 24 (5) ◽  
pp. 673 ◽  
Author(s):  
Jian Wang ◽  
D. S. Letham ◽  
Edwina Cornish ◽  
K. Wei ◽  
C. H. Hocart ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chalcone Synthase ◽  
Hormonal Control ◽  
Mature Leaf ◽  
Cytokinin Oxidase ◽  
Endogenous Cytokinin ◽  
Gus Gene ◽  
Ipt Gene ◽  
Cytokinin Level ◽  
Gus Gene Expression

The expression of GUS and ipt genes under control of a chalcone synthase (chs) promoter (PCHS) has been determined in tobacco (Nicotiana tabacum L.) plants and related to the development of plants expressing the chimaeric PCHS -ipt gene. GUS gene expression, which served as a model for the expression of the ipt gene, was highest in the internal phloem tissue of stems, in mature leaf laminae and in the upper part of corollas when fully open. Expression of the PCHS -ipt gene was assessed by quantifying the cytokinins produced, by determining incorporation of [3H]adenine into cytokinins and by quantifying ipt mRNA. Results from these studies were in general agreement with those based on expression of the PCHS -GUS gene. The chs promoter controlled expression of the ipt gene with some degree of tissue and temporal specificity. Expression of the ipt gene markedly elevated the cytokinin level in mature leaf laminae and the upper stems of flowering plants. The former was associated with retardation of leaf senescence and increased rates of transpiration due to changes in number, size and aperture of stomata, while the latter was associated with development of lateral shoots. In shoot tip cultures, 2-fold elevations in endogenous cytokinin level caused clear changes in development and this is discussed in relation to current concepts concerning the hormonal control of plant development. Using the transgenic tobacco tissues, it was shown that cis-zeatin is a substrate for cytokinin oxidase, that cis-zeatin is not converted to trans-zeatin in these tissues and that the endogenous cytokinin level influences the level of cytokinin oxidase activity in tissue and the rate of degradation of exogenous zeatin riboside to adenosine.

Growth Stages of Peanut (Arachis hypogaea L.)1

1982 ◽  
Vol 9 (1) ◽  
pp. 35-40 ◽  
Author(s):  
K. J. Boote
Keyword(s):  
Arachis Hypogaea ◽  
Plant Development ◽  
Growth Stage ◽  
Cultural Practices ◽  
Cotyledonary Node ◽  
Main Stem ◽  
Growth Stages ◽  
Node Number ◽  
Arachis Hypogaea L ◽  
Harvest Maturity

Abstract Uniform growth stage descriptions were developed for peanut based on visually observable vegetative (V) and reproductive (R) events. The V stage was determined by counting the number of developed nodes on the main stem, beginning with the cotyledonary node as zero. The last node counted must have its tetrafoliolate leaf sufficiently expanded so the leaflets are unfolded and flat in appearance. The R stages proposed are R1 (beginning bloom), R2 (beginning peg), R3 (beginning pod), R4 (full pod), R5 (beginning seed), R6 (full seed), R7 (beginning maturity), R8 (harvest maturity), and R9 (over mature pod). The V and R stages can be measured separately and concurrently and apply to populations or single plants. For populations, a given stage is reached when 50% of the plants sampled have achieved the specified node number or have one or more flowers, pegs, pods, or seeds exhibiting the specified trait. The stages apply to both Spanish and Virginia type cultivars. The proposed standard descriptions of peanut plant development should aid in peanut research planning and communication and should assist extension recommendation of timing of cultural practices.

Promotion of shoot development and tuberisation in potato by expression of a chimaeric cytokinin synthesis gene at normal and elevated CO2 levels

2010 ◽  
Vol 37 (1) ◽  
pp. 43 ◽  
Author(s):  
Guo-Qing Tao ◽  
D. Stuart Letham ◽  
Jean W. H. Yong ◽  
Kerong Zhang ◽  
Peter C. L. John ◽  
...  
Keyword(s):  
Gene Expression ◽  
Solanum Tuberosum L ◽  
Shoot Development ◽  
Main Stem ◽  
Stem Length ◽  
Tuber Weight ◽  
Ipt Gene ◽  
Cytokinin Biosynthesis ◽  
Node Number ◽  
Apical Bud

The bacterial cytokinin biosynthesis gene ipt under control of a chalcone synthase promoter (PCHS) was introduced into potato (Solanum tuberosum L.). Two transgenic lines were selected for detailed study, because in these, root development was reduced only moderately, thus, enabling the plants to be grown in pots. Expression of the PCHS-ipt gene elevated the level of zeatin cytokinins markedly in the apical bud, subapical stems and leaves. The transgenic (IPT) plants exhibited a lower and denser leaf canopy relative to wild-type (WT) plants owing to reduction in main stem length, increase in node number per stem and promotion of lateral shoot development. Main stem diameter was increased markedly due to promotion of cell division associated with activation of cyclin-dependent kinase in the subapical stem. Expression of the PCHS-ipt gene induced aerial stolons, promoted growth of underground stolons and increased tuber number but reduced tuber weight and nitrogen content. The gene expression also increased pinnae and pinnule number per leaf, increased thickness of pinnae and promoted transpiration, photosynthesis and stomatal conductance – effects monitored by gas exchange and 18O and 13C analysis. The elevation of [CO2] to 900 μmol mol–1 promoted growth of both WT and IPT plants, ameliorated the negative effect of high cytokinin on tuber weight and interacted additively with ipt gene expression to promote stem growth.

scholarly journals CHARACTERATION OF AIR MOVEMENT PATTERNS AND VELOCITY EFFECIS ON PLANT DEVELOPMENT IN A GROWTH CHAMBER

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1151a-1151
Author(s):  
R.L. Korthals” ◽  
S.L. Knight ◽  
L.L. Christianson
Keyword(s):  
Plant Development ◽  
Horizontal Velocity ◽  
Growth Chamber ◽  
Hot Wire ◽  
Plant Growth And Development ◽  
Air Velocity ◽  
Experimental Conditions ◽  
Node Number ◽  
Air Movement ◽  
Practical Implications

Chrysanthemum, wheat, and soybean were grown in a growth chamber to study the effects of airflow direction, velocity, and turbulence on vegetative growth. These three plant species were chosen to examine how plants with different leaf architectures and morphology are influenced by varying air velocity and pattern. A hot wire anemometer accurate to ±0.025 m s-1 and capable of responding to 50 khz turbulent velocity fluctuations was used to characterize the environment in a growth chamber under three different experimental conditions: <0.50 m s-1 horizontal velocity, >1.00 m s-1 horizontal velocity, and <0.50 m s-1 vertical velocity. Plants were grown under the three different treatments for five weeks with plant height, width, stem diameter, and node number, and fresh and dry weights of leaves, stem, and roots determined at three internals throughout each experiment. Tire variation in plant development resulting from the different treatments has practical implications for using ventilation to aid in controlling plant growth and development.

scholarly journals Root phenotypes of young wheat plants grown in controlled environments show inconsistent correlation with mature root traits in the field

2020 ◽  
Vol 71 (16) ◽  
pp. 4751-4762 ◽  
Author(s):  
Sarah M Rich ◽  
Jack Christopher ◽  
Richard Richards ◽  
Michelle Watt
Keyword(s):  
Plant Development ◽  
Field Experiments ◽  
Primary Root ◽  
Root Traits ◽  
Field Trials ◽  
Controlled Environment ◽  
Nodal Root ◽  
Controlled Environments ◽  
Root Types ◽  
Mature Root

Abstract Using a field to lab approach, mature deep-rooting traits in wheat were correlated to root phenotypes measured on young plants from controlled conditions. Mature deep-rooting root traits of 20 wheat genotypes at maturity were established via coring in three field trials across 2 years. Field traits were correlated to phenotypes expressed by the 20 genotypes after growth in four commonly used lab screens: (i) soil tubes for root emergence, elongation, length, and branching at four ages to 34 days after sowing (DAS); (ii) paper pouches 7 DAS and (iii) agar chambers for primary root (PR) number and angles at 8 DAS; and (iv) soil baskets for PR and nodal root (NR) number and angle at 42 DAS. Correlations between lab and field root traits (r2=0.45–0.73) were highly inconsistent, with many traits uncorrelated and no one lab phenotype correlating similarly across three field experiments. Phenotypes most positively associated with deep field roots were: longest PR and NR axiles from the soil tube screen at 20 DAS; and narrow PR angle and wide NR angle from soil baskets at 42 DAS. Paper and agar PR angles were positively and significantly correlated to each other, but only wide outer PRs in the paper screen correlated positively to shallower field root traits. NR phenotypes in soil baskets were not predicted by PR phenotypes in any screen, suggesting independent developmental controls and value in measuring both root types in lab screens. Strong temporal and edaphic effects on mature root traits, and a lack of understanding of root trait changes during plant development, are major challenges in creating controlled-environment root screens for mature root traits in the field.

scholarly journals The evolutionary-developmental analysis of plant microRNAs

2010 ◽  
Vol 365 (1539) ◽  
pp. 469-476 ◽  
Author(s):  
Sophie Jasinski ◽  
Aurélie C. M. Vialette-Guiraud ◽  
Charles P. Scutt
Keyword(s):  
Plant Development ◽  
Sequence Data ◽  
Leaf Shape ◽  
Gene Identification ◽  
Test Case ◽  
Last Common Ancestor ◽  
Mirna Genes ◽  
Step Procedure ◽  
Evo Devo ◽  
Developmental Analysis

MicroRNAs (miRNAs) control many important aspects of plant development, suggesting these molecules may also have played key roles in the evolution of developmental processes in plants. However, evolutionary-developmental (evo-devo) studies of miRNAs have been held back by technical difficulties in gene identification. To help solve this problem, we have developed a two-step procedure for the efficient identification of miRNA genes in any plant species. As a test case, we have studied the evolution of the MIR164 family in the angiosperms. We have identified novel MIR164 genes in three species occupying key phylogenetic positions and used these, together with published sequence data, to partially reconstruct the evolution of the MIR164 family since the last common ancestor of the extant flowering plants. We use our evolutionary reconstruction to discuss potential roles for MIR164 genes in the evolution of leaf shape and carpel closure in the angiosperms. The techniques we describe may be applied to any miRNA family and should thus enable plant evo-devo to begin to investigate the contributions miRNAs have made to the evolution of plant development.

scholarly journals ABROBACTERIUM-MEDIATED INTRODUCTION OF CHALCONE SYNTHASE GENE INTO CHRYSANTHEMUM AND PERFORMANCE OF COLOR-MODIFIED TRANSGENIC PLANTS.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 659f-659 ◽  
Author(s):  
E. Firoozabady ◽  
C. Lemieux ◽  
J. Nicholas ◽  
A. Otten ◽  
M. Akerboom ◽  
...  
Keyword(s):  
Chalcone Synthase ◽  
Color Change ◽  
Transformation Method ◽  
35S Promoter ◽  
Flower Number ◽  
Pigment Analysis ◽  
Transformed Plants ◽  
Chalcone Synthase Gene ◽  
Sense Orientation ◽  
And Performance

We developed an Agrobacterium-mediated leaf disk transformation method for chrysanthemum. We introduced a chimeric chalcone synthase (CHS) gene isolated from chrysanthemum into cv. Moneymaker (pink type) to produce white-flowered plants. The CHS coding sequence was in antisense or sense orientation relative to the CaMV 35S promoter. 3.6% (3/83) antisense-transformed plants and 1.5% (2/133) sense-transformed plants produced completely white flowers. Pigment analysis revealed that this was due to a block at CHS. To study stability of color change of the white Moneymaker plants. Moneymaker, a Moneymaker regenerant, an antisense white (2706),and a sense white (31435) were compared. There was no difference between Moneymaker and the regenerant. Both 2706 and 31435 were vegetatively propagated with good stability; all plants produced white or very pale pink flowers. 2706 flowered 7 days late and 31435 10-12 days late. Flower number was similar for all four lines tested.

Differential usage of photoreceptors for chalcone synthase gene expression during plant development

1992 ◽  
Vol 2 (6) ◽  
pp. 899-906 ◽  
Author(s):  
Hanns Frohnmeyer ◽  
Bruno Ehmann ◽  
Thomas Kretsch ◽  
Martin Rocholl ◽  
Klaus Harter ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Development ◽  
Chalcone Synthase ◽  
Chalcone Synthase Gene

scholarly journals Pontin/Reptin-associated complexes differentially impact plant development and viral pathology

2021 ◽  
Author(s):  
Snigdha Chatterjee ◽  
Min Xu ◽  
Elena M. Shemyakina ◽  
Jacob O Brunkard
Keyword(s):  
Chromatin Remodeling ◽  
Plant Development ◽  
Stress Responses ◽  
Leaf Shape ◽  
Potato Virus X ◽  
Null Alleles ◽  
Comparative Approach ◽  
Virus Induced Gene Silencing ◽  
Tor Kinase ◽  
Delayed Flowering

Pontin and Reptin are essential eukaryotic AAA+ ATPases that work together in several multiprotein complexes, contributing to chromatin remodeling and TARGET OF RAPAMCYIN (TOR) kinase complex assembly, among other functions. Null alleles of pontin or reptin are gametophyte lethal in plants, which has hindered studies of their crucial roles in plant biology. Here, we used virus-induced gene silencing (VIGS) to interrogate the functions of Pontin and Reptin in plant growth and physiology, focusing on Nicotiana benthamiana, a model species for the agriculturally significant Solanaceae family. Silencing either Pontin or Reptin caused pleiotropic developmental and physiological reprogramming, including aberrant leaf shape, reduced apical growth, delayed flowering, increased branching, chlorosis, and decreased spread of the RNA viruses Tobacco mosaic virus (TMV) and Potato virus X (PVX). To dissect these pleiotropic phenotypes, we took a comparative approach and silenced expression of key genes that encode subunits of each of the major Pontin/Reptin-associated chromatin remodeling or TOR complexes (INO80, SWR-C/PIE1, TIP60, TOR, and TELO2). We found that many of the pontin/reptin phenotypes could be attributed specifically to disruption of one of these complexes, with tip60 and tor knockdown plants each phenocopying a large subset of pontin/reptin phenotypes. We conclude that Pontin/Reptin complexes are crucial for proper plant development, physiology, and stress responses, highlighting the multifaceted roles these conserved enzymes have evolved in eukaryotic cells.

HEN1functions pleiotropically inArabidopsisdevelopment and acts in C function in the flower

Development ◽  
2002 ◽  
Vol 129 (5) ◽  
pp. 1085-1094 ◽  
Author(s):  
Xuemei Chen ◽  
Jun Liu ◽  
Yulan Cheng ◽  
Dongxuan Jia
Keyword(s):  
Plant Development ◽  
Leaf Shape ◽  
Reproductive Organ ◽  
Genetic Screen ◽  
Multiple Roles ◽  
Organ Identity ◽  
New Gene ◽  
Rosette Leaf ◽  
Novel Protein ◽  
Floral Homeotic

Four classes of floral homeotic MADS domain proteins specify the identities of the four organ types in an Arabidopsis flower. While the activities of the MADS domain proteins are essentially confined to the flower or to the inflorescence, several genes, such as APETALA2, HUA1 and HUA2, also act outside the flower in addition to their organ identity functions inside the flower. We identified a new gene, HUA ENHANCER 1 (HEN1) from a sensitized genetic screen in the hua1-1 hua2-1 background that is compromised in floral homeotic C function. We showed that HEN1, like the C function gene AGAMOUS, acts to specify reproductive organ identities and to repress A function. HEN1 also shares AG’s non-homeotic function in controlling floral determinacy. HEN1 may achieve these functions by regulating the expression of AG. hen1 single mutants exhibit pleiotropic phenotypes such as reduced organ size, altered rosette leaf shape and increased number of coflorescences, during most stages of development. Therefore, HEN1, like the A function gene AP2, plays multiple roles in plant development as well as acting in organ identity specification in the flower. HEN1 codes for a novel protein and is expressed throughout the plant.

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