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Induction of PtoCDKB and PtoCYCB transcription by temperature during cambium reactivation in Populus tomentosa Carr.

Li WF, Ding Q, Chen JJ, Cui KM, He XQ - J. Exp. Bot. (2009)

Bottom Line: Climatic data analysis showed a correlation between daily air temperature and PtoCDKB and PtoCYCB expression patterns.The results suggest that, in deciduous hardwood P. tomentosa growing in a temperate zone, the temperature in early spring is a vital environmental factor for cambium reactivation.The increasing temperature in early spring may induce CDKB and CYCB homologue transcription in the cambium region, which is necessary for cambium cell division.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, PR China.

ABSTRACT
Cell cycle progression requires interaction between cyclin-dependent kinase B (CDKB) and cyclin B (CYCB). The seasonal expression patterns of the CDKB and CYCB homologues from Populus tomentosa Carr. were investigated, and effects of temperature and exogenous indole-3-acetic acid (IAA) on their expression were further studied in water culture experiments. Based on the differential responses of dormant cambium cells to exogenous IAA, four stages of cambium dormancy were confirmed for P. tomentosa: quiescence 1 (Q1), rest, quiescence 2-1 (Q2-1), and quiescence 2-2 (Q2-2). PtoCDKB and PtoCYCB transcripts were strongly expressed in the active phases, weakly in Q1, and almost undetectable from rest until late Q2-2. Climatic data analysis showed a correlation between daily air temperature and PtoCDKB and PtoCYCB expression patterns. Water culture experiments with temperature treatment further showed that a low temperature (4 degrees C) kept PtoCDKB and PtoCYCB transcripts at undetectable levels, while a warm temperature (25 degrees C) induced their expression in the cambium region. Meanwhile, water culture experiments with exogenous IAA treatment showed that induction of PtoCDKB and PtoCYCB transcription was independent of exogenous IAA. The results suggest that, in deciduous hardwood P. tomentosa growing in a temperate zone, the temperature in early spring is a vital environmental factor for cambium reactivation. The increasing temperature in early spring may induce CDKB and CYCB homologue transcription in the cambium region, which is necessary for cambium cell division.

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Statistical analysis of the effect of exogenous IAA on cambium reactivation of 1- or 2-year-old dormant cuttings of P. tomentosa in water culture. Cell layers of IAA-treated cuttings from late September to the end of October and from late December to the middle of March increased (P <0.05), while from early November to late December they showed no change (P >0.05. Cell layers of lanolin-treated cuttings from late September to late January showed no change (P >0.05), but they increased from early February to the middle of March (P <0.05). Cell layers = cambium cell layers+recently formed xylem cell layers+recently formed phloem cell layers. The P-value was generated between an IAA-treated cutting and an intact control cutting or beteeeen a lanolin-treated cutting and an intact control cutting at each time point.
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fig2: Statistical analysis of the effect of exogenous IAA on cambium reactivation of 1- or 2-year-old dormant cuttings of P. tomentosa in water culture. Cell layers of IAA-treated cuttings from late September to the end of October and from late December to the middle of March increased (P <0.05), while from early November to late December they showed no change (P >0.05. Cell layers of lanolin-treated cuttings from late September to late January showed no change (P >0.05), but they increased from early February to the middle of March (P <0.05). Cell layers = cambium cell layers+recently formed xylem cell layers+recently formed phloem cell layers. The P-value was generated between an IAA-treated cutting and an intact control cutting or beteeeen a lanolin-treated cutting and an intact control cutting at each time point.

Mentions: The stage of cambium dormancy in P. tomentosa grown in natural conditions was determined based upon the differential responses of cambium cells to exogenous IAA according to the character of rest and quiescence described by Little and Bonga (1974). Anatomical examination and statistical analysis were conducted to assess the response of cambium cells to exogenous IAA according to the methods of Cui et al. (1992) and Mwange et al. (2003). After 3 weeks of water culture with exogenous IAA treatment, in the cambium of lanolin-treated bud-free cuttings sampled from late September to late January of the following year, no change in cell layers was found (Figs 1C, F, I, and 2; P >0.05), compared with their intact control. Interestingly, in the cuttings receiving the same treatment harvested from early February to the middle of March, cell layers increased compared with their intact control (Figs 1L and 2; P <0.05).


Induction of PtoCDKB and PtoCYCB transcription by temperature during cambium reactivation in Populus tomentosa Carr.

Li WF, Ding Q, Chen JJ, Cui KM, He XQ - J. Exp. Bot. (2009)

Statistical analysis of the effect of exogenous IAA on cambium reactivation of 1- or 2-year-old dormant cuttings of P. tomentosa in water culture. Cell layers of IAA-treated cuttings from late September to the end of October and from late December to the middle of March increased (P <0.05), while from early November to late December they showed no change (P >0.05. Cell layers of lanolin-treated cuttings from late September to late January showed no change (P >0.05), but they increased from early February to the middle of March (P <0.05). Cell layers = cambium cell layers+recently formed xylem cell layers+recently formed phloem cell layers. The P-value was generated between an IAA-treated cutting and an intact control cutting or beteeeen a lanolin-treated cutting and an intact control cutting at each time point.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2692011&req=5

fig2: Statistical analysis of the effect of exogenous IAA on cambium reactivation of 1- or 2-year-old dormant cuttings of P. tomentosa in water culture. Cell layers of IAA-treated cuttings from late September to the end of October and from late December to the middle of March increased (P <0.05), while from early November to late December they showed no change (P >0.05. Cell layers of lanolin-treated cuttings from late September to late January showed no change (P >0.05), but they increased from early February to the middle of March (P <0.05). Cell layers = cambium cell layers+recently formed xylem cell layers+recently formed phloem cell layers. The P-value was generated between an IAA-treated cutting and an intact control cutting or beteeeen a lanolin-treated cutting and an intact control cutting at each time point.
Mentions: The stage of cambium dormancy in P. tomentosa grown in natural conditions was determined based upon the differential responses of cambium cells to exogenous IAA according to the character of rest and quiescence described by Little and Bonga (1974). Anatomical examination and statistical analysis were conducted to assess the response of cambium cells to exogenous IAA according to the methods of Cui et al. (1992) and Mwange et al. (2003). After 3 weeks of water culture with exogenous IAA treatment, in the cambium of lanolin-treated bud-free cuttings sampled from late September to late January of the following year, no change in cell layers was found (Figs 1C, F, I, and 2; P >0.05), compared with their intact control. Interestingly, in the cuttings receiving the same treatment harvested from early February to the middle of March, cell layers increased compared with their intact control (Figs 1L and 2; P <0.05).

Bottom Line: Climatic data analysis showed a correlation between daily air temperature and PtoCDKB and PtoCYCB expression patterns.The results suggest that, in deciduous hardwood P. tomentosa growing in a temperate zone, the temperature in early spring is a vital environmental factor for cambium reactivation.The increasing temperature in early spring may induce CDKB and CYCB homologue transcription in the cambium region, which is necessary for cambium cell division.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, PR China.

ABSTRACT
Cell cycle progression requires interaction between cyclin-dependent kinase B (CDKB) and cyclin B (CYCB). The seasonal expression patterns of the CDKB and CYCB homologues from Populus tomentosa Carr. were investigated, and effects of temperature and exogenous indole-3-acetic acid (IAA) on their expression were further studied in water culture experiments. Based on the differential responses of dormant cambium cells to exogenous IAA, four stages of cambium dormancy were confirmed for P. tomentosa: quiescence 1 (Q1), rest, quiescence 2-1 (Q2-1), and quiescence 2-2 (Q2-2). PtoCDKB and PtoCYCB transcripts were strongly expressed in the active phases, weakly in Q1, and almost undetectable from rest until late Q2-2. Climatic data analysis showed a correlation between daily air temperature and PtoCDKB and PtoCYCB expression patterns. Water culture experiments with temperature treatment further showed that a low temperature (4 degrees C) kept PtoCDKB and PtoCYCB transcripts at undetectable levels, while a warm temperature (25 degrees C) induced their expression in the cambium region. Meanwhile, water culture experiments with exogenous IAA treatment showed that induction of PtoCDKB and PtoCYCB transcription was independent of exogenous IAA. The results suggest that, in deciduous hardwood P. tomentosa growing in a temperate zone, the temperature in early spring is a vital environmental factor for cambium reactivation. The increasing temperature in early spring may induce CDKB and CYCB homologue transcription in the cambium region, which is necessary for cambium cell division.

Show MeSH
Related in: MedlinePlus