T-DNA genes to study plant development: precocious tuberisation and enhanced cytokinins in A. tumefaciens transformed potato

Ooms, G.; Lenton, John R.

doi:10.1007/bf00020638

Cited by 47 publications

(23 citation statements)

References 36 publications

(44 reference statements)

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“…We exploited the IPT gene from Agrobacterium to enhance endogenous CK levels. As reported before (Ooms and Lenton, 1985;Macháčková et al, 1997), our transgenic potato plants hardly formed roots and exhibited a stunted, bushy phenotype with small leaflets. Hence, only one weakly IPT-expressing line formed enough tubers of similar size as the wild type to be suitable for further experiments.…”

Section: Ck Is Essential For Bud Breaksupporting

confidence: 83%

“…Bud break was followed by a phase of growth arrest before further sprout growth could be detected, probably due to a hormonal and/or metabolic imbalance. Furthermore, transgenic potato plants transformed with T-DNA from Agrobacterium to increase CK biosynthesis displayed a variety of phenotypic changes, including premature sprouting (Ooms and Lenton, 1985). We exploited the IPT gene from Agrobacterium to enhance endogenous CK levels.…”

Section: Ck Is Essential For Bud Breakmentioning

confidence: 99%

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Reactivation of Meristem Activity and Sprout Growth in Potato Tubers Require Both Cytokinin and Gibberellin

et al. 2010

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Reactivation of dormant meristems is of central importance for plant fitness and survival. Due to their large meristem size, potato (Solanum tuberosum) tubers serve as a model system to study the underlying molecular processes. The phytohormones cytokinins (CK) and gibberellins (GA) play important roles in releasing potato tuber dormancy and promoting sprouting, but their mode of action in these processes is still obscure. Here, we established an in vitro assay using excised tuber buds to study the dormancy-releasing capacity of GA and CK and show that application of gibberellic acid (GA 3 ) is sufficient to induce sprouting. In contrast, treatment with 6-benzylaminopurine induced bud break but did not support further sprout growth unless GA 3 was administered additionally. Transgenic potato plants expressing Arabidopsis (Arabidopsis thaliana) GA 20-oxidase or GA 2-oxidase to modify endogenous GA levels showed the expected phenotypical changes as well as slight effects on tuber sprouting. The isopentenyltransferase (IPT) from Agrobacterium tumefaciens and the Arabidopsis cytokinin oxidase/dehydrogenase1 (CKX) were exploited to modify the amounts of CK in transgenic potato plants. IPT expression promoted earlier sprouting in vitro. Strikingly, CKX-expressing tubers exhibited a prolonged dormancy period and did not respond to GA 3 . This supports an essential role of CK in terminating tuber dormancy and indicates that GA is not sufficient to break dormancy in the absence of CK. GA 3 -treated wild-type and CKX-expressing tuber buds were subjected to a transcriptome analysis that revealed transcriptional changes in several functional groups, including cell wall metabolism, cell cycle, and auxin and ethylene signaling, denoting events associated with the reactivation of dormant meristems.

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Section: Ck Is Essential For Bud Breaksupporting

confidence: 83%

Section: Ck Is Essential For Bud Breakmentioning

confidence: 99%

Reactivation of Meristem Activity and Sprout Growth in Potato Tubers Require Both Cytokinin and Gibberellin

et al. 2010

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“…Taking such percentages it can be calculated from experiments and assumptions described by Goldberg et al (l l) for polysomal RNA in tobacco leaves that Tcyt was expressed on average at five to ten transcript 4 molecules per cell for Mb 1501B shoots and only on average at one to two Tcyt RNA molecules per cell for grafted plants and tubers. Note that this approximate fivefold reduction in the abundance of transcript 4 in transformed shoots following grafting is correlated with an average twenty-fold reduction in cytokinin level (26).…”

Section: Discussionmentioning

confidence: 93%

“…The plant tissues analysed were grown as described in the accompanying paper (26). For RNA analyses from shoot culture material only shoots without the callus tissue at their base was used.…”

Section: Plant Rna Isolationmentioning

confidence: 99%

Expression of shoot-inducing Ti TL-DNA in differentiated tissues of potato (Solanum tuberosum cv Maris Bard)

et al. 1985

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In potato line Mb1501B one or possibly two normal size Ti TL-DNA copies per tetraploid genome were detected by Southern blot analysis, but no TR-DNA. The TL-DNA probably contained the entire transposon Tn1831 inserted at the T-DNA auxin gene for transcript 2. Northern blot analyses of the steady-state RNA in different Mb1501B tissues isolated from (i) shoots cultured in vitro (ii) grafted plants and (iii) tubers, showed that that TL-DNA transcripts 3, 4, 6a and 7 were expressed most abundantly in the cultured shoots. They formed approximately 0.0023 to 0.0007% of the total poly(A) RNA. Transcripts 1, 5 and 6b were not detected in any of the tissues analysed. This indicated even lower levels of expression (below approximately 0.0001% of the total poly(A) RNA or, making certain assumptions, an abundance of less than one T-DNA derived RNA molecule per cell). As expected, transcript 2 was not detected in any of the Mb1501B tissues. The abundance of the transcripts was reduced in grafted plants and tubers compared with cultured shoots with the greatest decrease (5×) for transcripts 4, 6a and 7. Transcript 4, the one most responsible for the changed growth and development of Mb 1501 B, formed approximately 0.0003% of the poly(A) RNA from both grafted plants and tubers.

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“…Delayed leaf senescence has also been observed following the exogenous application of cytokinin (Richmond and Lang, 1957). Other reported effects of endogenous cytokinin overproduction include the production of the defense-related genes for extensin, chitinase, and PR1 (Memelink et al, 1987), and increased tuber formation from potato plants (Ooms and Lenton, 1985).…”

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confidence: 97%

Controlled Cytokinin Production in Transgenic Tobacco Using a Copper-Inducible Promoter

et al. 1998

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The cytokinin group of plant hormones regulates aspects of plant growth and development, including the release of lateral buds from apical dominance and the delay of senescence. In this work the native promoter of a cytokinin synthase gene (ipt) was removed and replaced with a Cu-controllable promoter. Tobacco (Nicotiana tabacum L. cv tabacum) transformed with this Cu-inducible ipt gene (Cu-ipt) was morphologically identical to controls under noninductive conditions in almost all lines produced. However, three lines grew in an altered state, which is indicative of cytokinin overproduction and was confirmed by a full cytokinin analysis of one of these lines. The in vitro treatment of morphologically normal Cu-ipt transformants with Cu 2؉ resulted in delayed leaf senescence and an increase in cytokinin concentration in the one line analyzed. In vivo, inductive conditions resulted in a significant release of lateral buds from apical dominance. The morphological changes seen during these experiments may reflect the spatial aspect of control exerted by this gene expression system, namely expression from the root tissue only. These results confirmed that endogenous cytokinin concentrations in tobacco transformants can be temporally and spatially controlled by the induction of ipt gene expression through the Cu-controllable gene-expression system.

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T-DNA genes to study plant development: precocious tuberisation and enhanced cytokinins in A. tumefaciens transformed potato

Cited by 47 publications

References 36 publications

Reactivation of Meristem Activity and Sprout Growth in Potato Tubers Require Both Cytokinin and Gibberellin

Reactivation of Meristem Activity and Sprout Growth in Potato Tubers Require Both Cytokinin and Gibberellin

Expression of shoot-inducing Ti TL-DNA in differentiated tissues of potato (Solanum tuberosum cv Maris Bard)

Controlled Cytokinin Production in Transgenic Tobacco Using a Copper-Inducible Promoter

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