Changes in Chloroplast Ultrastructure in Pssu-ipt Tobacco During Plant Ontogeny

Synková, Helena; Pechová, R.; Valcke, Roland

doi:10.1023/a:1025829017298

Cited by 9 publications

(2 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Analysis of the cytokinin content in these plants compared to the relative gene expression of the transgene clearly shows that overexpression of IPT or CKX has an effect on levels of the different cytokinin metabolites. This is in agreement with previous studies using P ssu-ipt or 35S:CKX1 transgenic tobacco plants (Synková et al 1999 , 2003 , 2006 ; Werner et al 2001 , 2008 ; Polanská et al 2007 ). These studies also show that an alteration of the endogenous cytokinin content has a tremendous effect on morphological level (root/shoot formation, chloroplast ultrastructure) but also functionally (effect on photosynthesis, sink-source relationship).…”

Section: Discussionsupporting

confidence: 93%

See 1 more Smart Citation

Selection of plastid- and nuclear-encoded reference genes to study the effect of altered endogenous cytokinin content on photosynthesis genes in Nicotiana tabacum

et al. 2009

View full text Add to dashboard Cite

Selection and use of appropriate reference genes as internal controls in real-time reverse transcription PCR (RT-PCR) assays is highly important for accurate quantification of gene expression levels. Since some photosynthetic genes are encoded in the nuclear genome and others in the chloroplast genome, we evaluated both nuclear-and plastid-encoded candidate reference genes. Six plastid-encoded candidate reference genes were derived from Arabidopsis microarray data and three plastid-and five nuclear-encoded reference genes were derived from literature. Cytokinins influence photosynthetic gene expression, so we evaluated the expression stability of the candidate reference genes in transgenic Nicotiana tabacum plants with elevated or diminished cytokinin content. We found that the most reliable strategy makes use of plastidencoded genes for normalizing plastid photosynthetic genes and nuclear-encoded reference genes for normalizing nuclear photosynthetic genes. Compared to the use of nuclear reference genes only, this approach assimilates any effects on transcriptional activity of chloroplasts or number of chloroplast. The best expression stabilities in Nicotiana tabacum were observed for the plastid-encoded references genes Nt-RPS3, Nt-NDHI and Nt-IN1 and for the nuclear-encoded genes Nt-ACT9, Nt-aTUB and Nt-SSU. These genes may be suitable for normalization of photosynthetic genes under other experimental conditions in Nicotiana tabacum, and orthologues of these genes may be suitable candidates for normalizing photosynthetic gene expression in other species.

show abstract

Section: Discussionsupporting

confidence: 93%

“…Our hypothesis is that cytokinins might affect the regulation of gene expression, since it was shown that cytokinins can influence chlorophyll biosynthesis (Reski 1994 ) and the electron transport chain (Synková et al . 2003 ).…”

Section: Discussionmentioning

confidence: 99%

Selection of plastid- and nuclear-encoded reference genes to study the effect of altered endogenous cytokinin content on photosynthesis genes in Nicotiana tabacum

et al. 2009

View full text Add to dashboard Cite

show abstract

Three-dimensional reconstruction of anomalous chloroplasts in transgenic ipt tobacco

Synková

Schnablová

Polanská

et al. 2005

Planta

View full text Add to dashboard Cite

Anomalies in the ultrastructure of chloroplasts, from transgenic ipt tobacco, overproducing endogenous cytokinins (CKs) were studied. Detailed analyses of CKs and their metabolites showed that Pssu-ipt tobacco contained enhanced contents of CKs both in leaves and in isolated chloroplasts. The role of CKs in the formation of anomalous structures is suggested. Pssu-ipt chloroplasts frequently formed the distinct peripheral reticulum with a system of caverns that often involved mitochondria and/or peroxisomes. Large crystalloids, which were found in chloroplasts of Pssu-ipt, occupied up to 16% of chloroplast volume. We suggested that the crystalloids were formed by LHC II aggregates. This was supported by analysis of the fluorescence emission spectra at 77 degrees K, chlorophyll a/b ratio, immunogold staining of the structures, and crystallographic unit size analysis.

show abstract

Isolation and characterization of paracrystalline structures from transgenic Pssu-ipt tobacco

Synková¹,

Schnablová²,

Hušák³

et al. 2005

Photosynt.

View full text Add to dashboard Cite

Distinct crystalloids were found in chloroplasts of transgenic Pssu-ipt tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) overproducing endogenous cytokinins. They were present both in rooted (T) and grafted (TC) transgenic plants contrary to control tobacco (C). The fractions enriched by crystalloids were isolated from chloroplasts using a continuous or a discontinuous Percoll gradient. Chlorophyll (Chl) fluorescence emission spectra at 77 K indicated the presence of aggregates of light-harvesting complex proteins (LHC2) that was not connected to reaction centres of photosystem 2 both in isolated chloroplasts and in the fraction of 80 % Percoll gradient from both types of transgenic tobacco. Further analyses, i.e. pigment contents, polypeptide composition by SDS-PAGE, and immunoblotting support our hypothesis that crystalloids inside chloroplasts of transgenic tobacco are formed by LHC2 aggregates. Treatment with two distinct detergents, chosen with respect to their effects (i.e. β-dodecyl maltoside or Triton X-100), resulted in different degree of disintegration of Chl a/b proteins in transgenic plants compared to the control. Electron microscopic observations and immunogold labelling with specific LHC2 antibodies carried on the resin embedded leaf sections or free suspensions of chloroplasts showed that gold particles were bound preferentially on the outer surface of crystalloids. Threedimensional reconstruction of chloroplasts and crystalloids proved that paracrystalline structures varied moderately in their size and took up a significant portion of total chloroplast volume.

show abstract

Changes in Chloroplast Ultrastructure in Pssu-ipt Tobacco During Plant Ontogeny

Cited by 9 publications

References 31 publications

Selection of plastid- and nuclear-encoded reference genes to study the effect of altered endogenous cytokinin content on photosynthesis genes in Nicotiana tabacum

Selection of plastid- and nuclear-encoded reference genes to study the effect of altered endogenous cytokinin content on photosynthesis genes in Nicotiana tabacum

Three-dimensional reconstruction of anomalous chloroplasts in transgenic ipt tobacco

Isolation and characterization of paracrystalline structures from transgenic Pssu-ipt tobacco

Contact Info

Product

Resources

About