The Roles of Phytohormones in Development as Studied in Transgenic Plants

Klee, Harry J.; Romano, Charles P.

doi:10.1080/713608064

Cited by 20 publications

(14 citation statements)

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“…Chemical inhibitors of hormone biosynthesis (e.g., aminoethoxyvinylglycine or competitive inhibitors of hormone action such as 2,5-norbornadiene in the case of ethylene) take time to discover and may have nonspecific effects. Genetic dissection through the use of mutants or gene silencing in transgenic plants is the most promising method of removing a putative signal molecule [Klee and Romano, 1994]. A number of approaches have been helpful, including overexpression or antisense of genes encoding biosynthetic enzymes and expression of precursor-degrading genes [Klee and Romano, 1994].…”

Section: Excisionmentioning

confidence: 99%

“…Genetic dissection through the use of mutants or gene silencing in transgenic plants is the most promising method of removing a putative signal molecule [Klee and Romano, 1994]. A number of approaches have been helpful, including overexpression or antisense of genes encoding biosynthetic enzymes and expression of precursor-degrading genes [Klee and Romano, 1994]. Although these methods avoid the uncertainties involved in exogenous application, they require a considerable investment in elucidating biosynthetic pathways, gene cloning, transformation, and regeneration, and thus cannot normally be used as an initial method to screen prospective signal molecules.…”

Section: Excisionmentioning

confidence: 99%

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Putative regulatory molecules in plants: evaluating melatonin

Tassel

O’Neill

2001

Journal of Pineal Research

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Numerous classes of chemicals have been considered as regulators of various aspects of plant growth and development. In evaluating these putative regulatory molecules, plant biologists have encountered a number of challenges, including: the problem of quantifying substances present at trace levels in extremely complex mixtures; difficulty in obtaining and interpreting phenotypic responses to exogenous applications; and, until recently, the inability to selectively alter endogenous levels of these substances. Melatonin (N-acetyl 5-methoxytryptamine), a methoxylated indoleamine, is a potential regulatory molecule found in plants. Although no specific phenotype is currently associated with melatonin or its analogs in higher plants, it has important and unique biological activity in many other taxa, from algae to primates. In these organisms, melatonin functions as a night signal, coordinating responses to diurnal and photoperiodic environmental cues. We assess the process by which melatonin has been evaluated in plants so far and find that many of the methods for melatonin analysis, which have been adopted from animal studies, are inappropriate for use with plant materials. Thus, despite some interesting preliminary reports, research supporting the case for melatonin as a plant regulator is still in its infancy.

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Section: Excisionmentioning

confidence: 99%

Section: Excisionmentioning

confidence: 99%

Putative regulatory molecules in plants: evaluating melatonin

Tassel

O’Neill

2001

Journal of Pineal Research

View full text Add to dashboard Cite

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“…A similar enzyme activity has also been observed in extracts from plant sources (Blackwell and Horgan, 1994;Chen and Ertl, 1994), but because of its instability, the enzyme has only been partially purified (Chen and Ertl, 1994). The I f T gene from Agrobacterium has been cloned and expressed in transgenic plants (Klee and Romano, 1994). However, there are no reports of plant DNA sequences with similarity to the bacterial I f T genes (Binns, 1994).…”

Section: Cytokininsmentioning

confidence: 99%

“…The first enzyme, tryptophan monooxygenase, converts tryptophan to indole-3-acetamide, which in turn is converted to IAA by indole-3-acetamide hydrolase. The genes encoding these enzymes have been used to alter IAA levels in transgenic plants (Klee and Romano, 1994).…”

Section: Auxinmentioning

confidence: 99%

The Five "Classical" Plant Hormones.

1997

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“…A similar strategy to manipulate hormone levels in plants has led to invaluable insights into the interplay among multiple hormonedependent pathways in plant growth and development (Klee and Romano, 1994) as well as their role in disease susceptibility (Gaffney et al, 1993). By analogy, we constructed transgenic Arabidopsis lines in which a mammalian enzyme, BV reductase (BVR), is expressed under regulatory control of a strong constitutive plant promoter.…”

Section: Introductionmentioning

confidence: 99%

Regulation of photomorphogenesis by expression of mammalian biliverdin reductase in transgenic Arabidopsis plants.

et al. 1997

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The photoregulatory activity of the phytochrome photoreceptor requires the synthesis and covalent attachment of the linear tetrapyrrole prosthetic group phytochromobilin. Because the mammalian enzyme biliverdin lXcv reductase (BVR) is able to functionally inactivate phytochromobilin in vitro, this investigation was undertaken to determine whether BVR expression in transgenic plants would prevent the synthesis of functionally active phytochrome in vivo. Here, we show that plastid-targeted, constitutive expression of BVR in Arabidopsis yields plants that display aberrant photomorphogenesis throughout their life cycle. Photobiological and biochemical analyses of three transgenic BVR lines exhibiting a 25-fold range of BVR expression established that the BVR-dependent phenotypes are light dependent, pleiotropic, and consonant with the loss of multiple phytochrome activities. Chlorophyll accumulation in BVR-expressing transgenic plants was particularly sensitive to increased light fluence rates, which is consistent with an important role for phytochrome in light tolerance. Under blue light, transgenic BVR plants displayed elongated hypocotyls but retained phototropic behavior and the ability to fully deetiolate. Directed BVR expression may prove to be useful for probing the cellular and developmental basis of phytochrome-mediated responses and for selective control of individual aspects of light-mediated plant growth and development.

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The Roles of Phytohormones in Development as Studied in Transgenic Plants

Cited by 20 publications

References 0 publications

Putative regulatory molecules in plants: evaluating melatonin

Putative regulatory molecules in plants: evaluating melatonin

The Five "Classical" Plant Hormones.

Regulation of photomorphogenesis by expression of mammalian biliverdin reductase in transgenic Arabidopsis plants.

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