Planta

, Volume 231, Issue 6, pp 1505–1511

Ecological functions and differentially expressed transcripts of translucent bracts in an alpine ‘glasshouse’ plant Rheum nobile (Polygonaceae)

  • Dongyuan Zhang
  • Bingbing Liu
  • Changming Zhao
  • Xu Lu
  • Dongshi Wan
  • Fei Ma
  • Litong Chen
  • Jianquan Liu
Rapid Communication

DOI: 10.1007/s00425-010-1133-x

Cite this article as:
Zhang, D., Liu, B., Zhao, C. et al. Planta (2010) 231: 1505. doi:10.1007/s00425-010-1133-x

Abstract

The molecular basis of many physiological and/or phenotypic adaptations of alpine plants remains largely unknown. The upper leaves of what are termed “glasshouse plants” have been transformed into translucent bracts that cover their inflorescences. This change in appearance is believed to allow such plants to maintain normal sexual reproduction under very cold conditions. Thus, it is hypothesized that the foliar roles of these bracts have been altered as an adaptation to alpine environments. In the present study, a test of this hypothesis revealed distinct physiological and anatomical differences (especially related to photosynthesis) between the bracts and normal leaves in one ‘glasshouse’ species, Rheum nobile Hook. f. and Thomson. A cDNA-AFLP analysis, was conducted to identify candidate genes involving differential expression in bracts and normal leaves, detected 323 (5.4%) transcript-derived fragments (TDFs) that were differentially expressed (up- or down-regulated) among 6,000 TDFs recovered. In total, 110 differentially expressed TDFs were sequenced, of which 52 were homologous to genes reported from other plants. More than half of the candidate genes represented by the unidentified TDFs may be specific to the Rheum lineage or have arisen through adaptive processes in alpine plants. All putative genes involved in photosynthesis had been down-regulated, while those related to stress and defense response were up-regulated in the bracts. These differentially expressed genes are highly congruent with physiological and anatomical differences between the bracts and normal leaves, indicating that they are associated with functions that confer a physiological advantage in alpine conditions.

Keywords

Adaptation Alpine plants Bracts cDNA-AFLPs Ecological functions 

Abbreviations

cDNA-AFLPs

Complementary DNA-amplified fragment length polymorphisms

TDFs

Transcript-derived fragments

UV

Ultraviolet

Fo

Minimal fluorescence yield

Fm

Maximal fluorescence yield

Fs

Steady-state fluorescence yield

Fm

Maximum light-adapted fluorescence yield

Fv

Ratio of variable

RT-PCR

Reverse transcription-polymerase chain reaction

ESTs

Expressed sequence tags

NCBI

National Center for Biotechnology Information

BLAST

Nucleotide Basic Local Alignment and Search Tools

GO

Gene ontology

HSPs

Heat shock proteins

Supplementary material

425_2010_1133_MOESM1_ESM.doc (67 kb)
Supplemental text: functional categorization of differentially expressed transcripts (DOC 67 kb)
425_2010_1133_MOESM2_ESM.doc (328 kb)
Supplemental Fig. S1: Expressed transcripts of the bracts and the normal leaves determined by cDNA-AFLP (DOC 327 kb)
425_2010_1133_MOESM3_ESM.doc (50 kb)
Supplemental Fig. S2: Comparisons of EST Rhn3554, EST Rhn3561 and Arabidopsis At2g09990 gene sequences. Special primers for EST Rhn3554 and Rhn3561 were designed and are indicated by the arrows (DOC 50 kb)
425_2010_1133_MOESM4_ESM.doc (36 kb)
Supplemental Table S1: Transcripts and primers used for RT-PCR analysis (DOC 36 kb)
425_2010_1133_MOESM5_ESM.doc (132 kb)
Supplemental Table S2: Selected list of the differentially expressed transcripts (transcript-derived fragments, TDFs) specific to bracts (B) or normal leaves (L) in R. nobile (DOC 131 kb)

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Dongyuan Zhang
    • 1
  • Bingbing Liu
    • 1
  • Changming Zhao
    • 1
  • Xu Lu
    • 1
  • Dongshi Wan
    • 1
  • Fei Ma
    • 1
  • Litong Chen
    • 1
  • Jianquan Liu
    • 1
  1. 1.Division of Molecular Ecology, Key Laboratory of Arid and Grassland Ecology, School of Life SciencesLanzhou UniversityLanzhouChina

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