The Regulation of Enzyme Synthesis in the Embryogenesis and Germination of Cotton

Walbrot,; Harris, Barry E.; Ls, Dure

doi:10.1016/b978-0-12-612979-3.50014-5

Cited by 7 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2). Because recent work (19) indicates that Act D may not inhibit all mRNA synthesis, the reasons for Act D insensitivity can not be deduced with certainty. Regardless of mechanism, the transition to insensitivity occurs at the same time as that reported for carboxypeptidase C (9).…”

Section: Discussionmentioning

confidence: 98%

“…In recent years, Dure and co-workers (7)(8)(9)(10)19) and Hammett and Katterman (5) have demonstrated the existence of preformed mRNA in cotton seeds and immature embryos. Ihle and Dure (7)(8)(9)(10), using sensitivity to Act D2 as the criterion for enzyme synthesis on this preformed mRNA, concluded that it coded in part for two "germination" enzymes, isocitrate lyase and carboxypeptidase C. The synthesis of this mRNA was reported to occur during seed maturation, with its subsequent translation prevented by endogenous ABA.…”

mentioning

confidence: 99%

“…First, Smith et al (17), using somewhat different methods of seed germination, were able to block production of isocitrate lyase activity with Act D. Second, Act D was shown to inhibit mRNA synthesis only 65% in this system (19). Thus, the effectiveness of the inhibitor on Cotton seeds are unusual in that nitrate induces considerable transitory nitrate reductase activity during germination (14,15).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Control of Enzyme Activities in Cotton Cotyledons during Maturation and Germination

Radin

Trelease

1976

Plant Physiol.

View full text Add to dashboard Cite

Actinomycin D at 10 jsg/nd strongy inhibited the increase in isocitrate lyase activity during germination of seeds and 40-day-old embryos of cotton (Gossypium hirsutum L.) when the germination period was preceded by 3 hours of soaking in the inhibitor solution. No inhibition was observed without the presoaking. Induction of nitrate reductase activity by nitrate was never inhibited by actinomycin D under the same conditions, and was frequently stimulated about 50%. Thus, the method of applying actinomycin D to the seeds and ovules could affect interpretation of its action. Abscisic acid at 5 ag/ml blocked production of isocitrate lyase activity in both pregermination treatments, but did not inhibit induction of nitrate reductase activity. Induction of nitrate reductase activity became insenitive to the two inhibitors during ovule maturation, at about 32 days after anthesis. The results indicate that isocitrate lyase, a germination enzyme, is not synthesized on preformed mRNA. In this respect, the appearance of activity in cotton resembles that in other specdes of fatty seeds. In contrast, induction of nitrate reductase activity, which is unnecessary for germination, apparently is not regulated at the level of transcription except in young ovules.In recent years, Dure and co-workers (7-10, 19) and Hammett and Katterman (5) have demonstrated the existence of preformed mRNA in cotton seeds and immature embryos. Ihle and Dure (7-10), using sensitivity to Act D2 as the criterion for enzyme synthesis on this preformed mRNA, concluded that it coded in part for two "germination" enzymes, isocitrate lyase and carboxypeptidase C. The synthesis of this mRNA was reported to occur during seed maturation, with its subsequent translation prevented by endogenous ABA. Such temporal separation of transcription and translation was considered to be an important regulatory mechanism for enzymes intimately associated with the germination process (2). We have reinvestigated the sensitivity of isocitrate lyase synthesis in cotton to Act D, with the intent, of reconciling the conflicting reports in the literature (9, 17). In addition, we have characterized the effects of Act D and ABA on nitrate reductase induction in germinating seeds and immature embryos, and compared its regulation by these compounds to the regulation of isocitrate lyase synthesis. MATERIALS AND METHODSChemicals. Act D, dithiothreitol, and ABA were purchased from Sigma Chemical Co.3 No differences in response to ABA were noted whether the source was cis, trans, or mixed isomers.Sources of Seeds and Ovules. We have found some variation in behavior among seedlots. For these experiments, seeds of cotton (Gossypium hirsutum L. cv. Deltapine 16), hand harvested in 1973, were acid delinted before use. Ovules of known ages were obtained from greenhouse-grown plants on which flowers were tagged at anthesis. The embryo fresh weights corresponded closely to those reported by Ihle and Dure (9).Genrination Methods. The major difference between the experiments of Ihle an...

show abstract

Section: Discussionmentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Control of Enzyme Activities in Cotton Cotyledons during Maturation and Germination

Radin

Trelease

1976

Plant Physiol.

View full text Add to dashboard Cite

show abstract

Control of enzyme activities in cotton cotyledons during maturation and germination

Choinski

Trelease

Doman

1981

Planta

View full text Add to dashboard Cite

Cotton (Gossypium hirsutum L.) embryos excised from bolls 38-43 d after anthesis and cultured in vitro for 4 d on a nutrient agar medium containing 3.8 μM abscisic acid (ABA) developed enzyme activity and accumulated insoluble protein, neutral lipid, and dry weight similar to embryos maturing on the plant. Inclusion of ABA in the medium prevented precosious germination and allowed continued increases in catalase, malate dehydrogenase, citrate synthase, aspartate aminotransferase, and β-oxidation enzyme activities as well as de-novo synthesis of malate synthase. Isocitrate lyase activity was not detectable in ABA-cultured embryos nor normally-developed embryos. Omission of sucrose from the medium resulted in near-doubling of the development of malate synthase activity, with minimal effects on the other enzyme activities. Addition of Actinomycin D, cordycepin, or cycloheximide to ABA-containing cultures did not overcome the observed inhibition of germination, but severely reduced both the appearance of new malate synthase activity and further production of other related enzyme activities. Thus, development of these enzyme activities in the presence of ABA appears dependent on transcription and translation, while inhibition of germination by ABA at this stage of development is not sensitive to the RNA- and protein-synthesis inhibitors. The results indicate that ABA does not prevent vivipary by suppressing translation of m-RNAs coding for isocitrate lyase and its companion enzymes, as previously proposed.

show abstract

Disappearance of stored polyadenylic acid and mRNA during early germination of radish (Raphanus sativus L.) embryo axes

Delseny

Aspart

Guitton

1977

Planta

View full text Add to dashboard Cite

Polyadenylic acid [poly (A)] is detected, characterized and quantitated in dry radish embryo axis RNA using a (3)H poly (U) probe. The amount of poly (A) gradually decreases after the onset of soaking, and, after a few hours, recovers to the initial level. This variation is shown to result from the addition of two opposed phenomena: the decay of stored poly (A) and the accumulation of newly synthesized poly (A). Stored poly (A), as well as the "in vivo" protein synthesis coded for by preformed mRNA, decreases during early germination with a half-life of two hours. As a whole, these results demonstrate that at least a fraction of the stored mRNA is translated as soon as the seed is soaked and that its role is rapidly taken over by newly-made mRNA.

show abstract

The Regulation of Enzyme Synthesis in the Embryogenesis and Germination of Cotton

Cited by 7 publications

References 21 publications

Control of Enzyme Activities in Cotton Cotyledons during Maturation and Germination

Control of Enzyme Activities in Cotton Cotyledons during Maturation and Germination

Control of enzyme activities in cotton cotyledons during maturation and germination

Disappearance of stored polyadenylic acid and mRNA during early germination of radish (Raphanus sativus L.) embryo axes

Contact Info

Product

Resources

About