High level of endogenous cytokinins in transgenic potato plantlets limits photosynthesis

Čatský, J.; Pospíšilová, Jana; Macháčková, Ivana; Synková, Helena; Wilhelmová, N.; Šesták, Z.

doi:10.1007/bf02925938

Cited by 13 publications

(2 citation statements)

References 19 publications

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“…Four of the six genes found to be induced by cytokinin in at least two publications belong to the LHCB2 family, encoding components of the light harvesting complexes. This is in accordance with the influence of cytokinin on the relative amount of light harvesting complexes (Šiffel et al, 1992; Catský et al, 1993) and on the accumulation of light harvesting complex mRNAs and proteins (Marziani Longo et al, 1990). …”

Section: Genome-wide Analysis Of the Cytokinin-regulated Transcriptomesupporting

confidence: 80%

Gene Regulation by Cytokinin in Arabidopsis

Brenner¹,

Ramireddy²,

Heyl³

et al. 2012

Front. Plant Sci.

144

133

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The plant hormone cytokinin realizes at least part of its signaling output through the regulation of gene expression. A great part of the early transcriptional regulation is mediated by type-B response regulators, which are transcription factors of the MYB family. Other transcription factors, such as the cytokinin response factors of the AP2/ERF family, have also been shown to be involved in this process. Additional transcription factors mediate distinct parts of the cytokinin response through tissue- and cell-specific downstream transcriptional cascades. In Arabidopsis, only a single cytokinin response element, to which type-B response regulators bind, has been clearly proven so far, which has 5′-GAT(T/C)-3′ as a core sequence. This motif has served to construct a synthetic cytokinin-sensitive two-component system response element, which is useful for monitoring the cellular cytokinin status. Insight into the extent of transcriptional regulation has been gained by genome-wide gene expression analyses following cytokinin treatment and from plants having an altered cytokinin content or signaling. This review presents a meta analysis of such microarray data resulting in a core list of cytokinin response genes. Genes encoding type-A response regulators displayed the most stable response to cytokinin, but a number of cytokinin metabolism genes (CKX4, CKX5, CYP735A2, UGT76C2) also belong to them, indicating homeostatic mechanisms operating at the transcriptional level. The cytokinin core response genes are also the target of other hormones as well as biotic and abiotic stresses, documenting crosstalk of the cytokinin system with other hormonal and environmental signaling pathways. The multiple links of cytokinin to diverse functions, ranging from control of meristem activity, hormonal crosstalk, nutrient acquisition, and various stress responses, are also corroborated by a compilation of genes that have been repeatedly found by independent gene expression profiling studies. Such functions are, at least in part, supported by genetic studies.

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Section: Genome-wide Analysis Of the Cytokinin-regulated Transcriptomesupporting

confidence: 80%

Gene Regulation by Cytokinin in Arabidopsis

Brenner¹,

Ramireddy²,

Heyl³

et al. 2012

Front. Plant Sci.

144

133

View full text Add to dashboard Cite

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“…The other transformant types had three (tobacco) to seven (potato) times smaller leaf area even if no increase of CK contents was detected. Other studies on transgenic plants bearing the ipt gene in various expression constructs generally confirmed the basic traits of such plants (Ondřej et al 1990, Šiffel et al 1992, Čatský et al 1993a,b, Pospíšilová et al 1997/98, Synková et al 1999, Jordi et al 2000, Synková and Valcke 2001, Lexa et al 2002. Leaf fresh masses of the NOT and MOD were very similar compared to the respective controls.…”

Section: Discussionmentioning

confidence: 65%

Extent of ipt gene expression and resulting amount of cytokinins affect activities of carboxylation enzymes in transgenic plants

Květoň¹

2006

Biol. plant.

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Three types of transgenic plants of Solanum tuberosum cvs. Kamýk and Oreb, and Nicotiana tabacum cvs. Maryland Mammoth and Trapezond were selected according to intensity of introduced ipt gene expression and resulting amount of synthesised cytokinins (CKs). In comparison with controls, original transgenic regenerants grown in vitro showed a massive increase of CK contents, in tobacco by 379 % and in potato by 159 % (MAS). Potato grown in soil from tubers of transgenic plants demonstrated a moderate increase (44 %) of CK contents (MOD). Transgenic tobacco grown from seeds in vitro did not show any significant change in CK contents (NOT). Initial (RuBPC i and RuBPO i ) and total (RuBPC t ) activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), and the activity of phosphoenolpyruvate carboxylase (PEPC) were not significantly affected by the transformation in the NOT plants. In the MOD plants, the RuBPCO activities were stimulated by up to 34 % whereas the PEPC activity was decreased by 17 %. On the other hand, all the measured enzyme activities were 32 -91 % lower in the MAS. Leaf area, fresh and dry masses, and chlorophyll and soluble protein contents also went down with increasing CK amounts in the transformants. Dependence of RuBPC i /RuBPO i and RuBPC t /PEPC ratios on the relative CK amounts in transgenic plants revealed that the individual enzyme activities were not affected uniformly. Endogenous CK contents in the MAS thus apparently exceeded an optimum needed for positive effects on many physiological traits and became a stress factor for such plants. plants with massive rise in CK contents; MOD -transgenic plants with moderate rise in CK contents; NOT -transgenic plants without rise in CK contents; PEPC -phosphoenolpyruvate carboxylase; RuBPC i,t , RuBPO i -carboxylating, resp. oxygenating operation of ribulose-1,5-bisphosphate carboxylase/oxygenase, subscripts: i -initial, t -total; RuBPCO -ribulose-1,5-bisphosphate carboxylase/oxygenase; SD -standard deviation; SE -standard error of the mean; Z -zeatin; ZR -zeatin riboside. Acknowledgements: I am grateful to Drs. P. Kostřica and M. Ondřej for providing experimental material (tubers, seeds, or in vitro regenerants), Drs. Ivana Macháčková and M. Strnad for performing cytokinin analyses, and Ing. Marie Zajícová for assisting with RuBPO activity assays. I also appreciate Ing. Marie Šimková for drawing the figures.

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Manipulation of Growth and Photosynthetic Processes by Plant Growth Regulators

Arteca

1996

Plant Growth Substances

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High level of endogenous cytokinins in transgenic potato plantlets limits photosynthesis

Cited by 13 publications

References 19 publications

Gene Regulation by Cytokinin in Arabidopsis

Gene Regulation by Cytokinin in Arabidopsis

Extent of ipt gene expression and resulting amount of cytokinins affect activities of carboxylation enzymes in transgenic plants

Manipulation of Growth and Photosynthetic Processes by Plant Growth Regulators

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