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Transcriptional profiling of Medicago truncatula meristematic root cells.

Holmes P, Goffard N, Weiller GF, Rolfe BG, Imin N - BMC Plant Biol. (2008)

Bottom Line: With bioinformatics tools developed to functionally annotate the Medicago genome array we could identify significant changes in metabolism, signalling and the differentially expression of 55 transcription factors in meristematic and non-meristematic roots.This is the first comprehensive analysis of M. truncatula root meristem cells using this genome array.This data will facilitate the mapping of regulatory and metabolic networks involved in the open root meristem of M. truncatula and provides candidates for functional analysis.

View Article: PubMed Central - HTML - PubMed

Affiliation: ARC Centre of Excellence for Integrative Legume Research, Genomic Interactions Group, Research School of Biological Sciences, Australian National University, Canberra ACT 2601, Australia. peta.holmes@anu.edu.au

ABSTRACT

Background: The root apical meristem of crop and model legume Medicago truncatula is a significantly different stem cell system to that of the widely studied model plant species Arabidopsis thaliana. In this study we used the Affymetrix Medicago GeneChip(R) to compare the transcriptomes of meristem and non-meristematic root to identify root meristem specific candidate genes.

Results: Using mRNA from root meristem and non-meristem we were able to identify 324 and 363 transcripts differentially expressed from the two regions. With bioinformatics tools developed to functionally annotate the Medicago genome array we could identify significant changes in metabolism, signalling and the differentially expression of 55 transcription factors in meristematic and non-meristematic roots.

Conclusion: This is the first comprehensive analysis of M. truncatula root meristem cells using this genome array. This data will facilitate the mapping of regulatory and metabolic networks involved in the open root meristem of M. truncatula and provides candidates for functional analysis.

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The Medicago root meristem. A median longitudinal section of the Medicago root stained with toluidine blue clearly shows that basic-open meristem architecture of M. truncatula, the zone of initials is not clearly divided into tiers; VC = vascular cylinder, C = cortex, E = epidermis, and RC = root cap; scale bar = 50 μm.
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Figure 1: The Medicago root meristem. A median longitudinal section of the Medicago root stained with toluidine blue clearly shows that basic-open meristem architecture of M. truncatula, the zone of initials is not clearly divided into tiers; VC = vascular cylinder, C = cortex, E = epidermis, and RC = root cap; scale bar = 50 μm.

Mentions: The M. truncatula RAM shows a characteristic basic open root meristem organisation (Figure 1). In the region where cells are dividing, it isn't possible to distinguish the initials amongst the tightly packed mass of new and elongating cells in the root tip. Our meristem section, 3 millimetres from the root tip, is comprised large group of undifferentiated cells, surrounded by some differentiated tissues including border cells, root cap and elongating cells that will form the vascular bundle, pericycle, endodermis, cortex and epidermis. Our non-meristematic section, one centimetre adjacent to the meristem, only contains the characteristic root tissue layers; root hairs occur in this region, rhizobial infection and lateral root initiation occur in this zone. These sections were chosen to correspond with earlier proteomic work on the Medicago root meristem [21] and because there are no described markers for specific cell types in the Medicago root meristem that could be used to create transgenic plants for a cell-type analysis.


Transcriptional profiling of Medicago truncatula meristematic root cells.

Holmes P, Goffard N, Weiller GF, Rolfe BG, Imin N - BMC Plant Biol. (2008)

The Medicago root meristem. A median longitudinal section of the Medicago root stained with toluidine blue clearly shows that basic-open meristem architecture of M. truncatula, the zone of initials is not clearly divided into tiers; VC = vascular cylinder, C = cortex, E = epidermis, and RC = root cap; scale bar = 50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2277415&req=5

Figure 1: The Medicago root meristem. A median longitudinal section of the Medicago root stained with toluidine blue clearly shows that basic-open meristem architecture of M. truncatula, the zone of initials is not clearly divided into tiers; VC = vascular cylinder, C = cortex, E = epidermis, and RC = root cap; scale bar = 50 μm.
Mentions: The M. truncatula RAM shows a characteristic basic open root meristem organisation (Figure 1). In the region where cells are dividing, it isn't possible to distinguish the initials amongst the tightly packed mass of new and elongating cells in the root tip. Our meristem section, 3 millimetres from the root tip, is comprised large group of undifferentiated cells, surrounded by some differentiated tissues including border cells, root cap and elongating cells that will form the vascular bundle, pericycle, endodermis, cortex and epidermis. Our non-meristematic section, one centimetre adjacent to the meristem, only contains the characteristic root tissue layers; root hairs occur in this region, rhizobial infection and lateral root initiation occur in this zone. These sections were chosen to correspond with earlier proteomic work on the Medicago root meristem [21] and because there are no described markers for specific cell types in the Medicago root meristem that could be used to create transgenic plants for a cell-type analysis.

Bottom Line: With bioinformatics tools developed to functionally annotate the Medicago genome array we could identify significant changes in metabolism, signalling and the differentially expression of 55 transcription factors in meristematic and non-meristematic roots.This is the first comprehensive analysis of M. truncatula root meristem cells using this genome array.This data will facilitate the mapping of regulatory and metabolic networks involved in the open root meristem of M. truncatula and provides candidates for functional analysis.

View Article: PubMed Central - HTML - PubMed

Affiliation: ARC Centre of Excellence for Integrative Legume Research, Genomic Interactions Group, Research School of Biological Sciences, Australian National University, Canberra ACT 2601, Australia. peta.holmes@anu.edu.au

ABSTRACT

Background: The root apical meristem of crop and model legume Medicago truncatula is a significantly different stem cell system to that of the widely studied model plant species Arabidopsis thaliana. In this study we used the Affymetrix Medicago GeneChip(R) to compare the transcriptomes of meristem and non-meristematic root to identify root meristem specific candidate genes.

Results: Using mRNA from root meristem and non-meristem we were able to identify 324 and 363 transcripts differentially expressed from the two regions. With bioinformatics tools developed to functionally annotate the Medicago genome array we could identify significant changes in metabolism, signalling and the differentially expression of 55 transcription factors in meristematic and non-meristematic roots.

Conclusion: This is the first comprehensive analysis of M. truncatula root meristem cells using this genome array. This data will facilitate the mapping of regulatory and metabolic networks involved in the open root meristem of M. truncatula and provides candidates for functional analysis.

Show MeSH