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Vascular gene expression: a hypothesis.

Martínez-Navarro AC, Galván-Gordillo SV, Xoconostle-Cázares B, Ruiz-Medrano R - Front Plant Sci (2013)

Bottom Line: Both lycophyte and bryophyte display motifs similar to those found in Arabidopsis with a significantly low E-value, while the chlorophytes showed either a different conserved motif or no conserved motif at all.These results suggest that these same genes are expressed coordinately in non-vascular plants; this coordinate expression may have been one of the prerequisites for the development of conducting tissues in plants.The presence of CmPP16, APL, FT, and YDA in chlorophytes suggests the recruitment of ancient regulatory networks for the development of the vascular tissue during evolution while OPS is a novel protein specific to vascular plants.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology and Bioengineering, CINVESTAV-IPN Mexico DF, Mexico.

ABSTRACT
The phloem is the conduit through which photoassimilates are distributed from autotrophic to heterotrophic tissues and is involved in the distribution of signaling molecules that coordinate plant growth and responses to the environment. Phloem function depends on the coordinate expression of a large array of genes. We have previously identified conserved motifs in upstream regions of the Arabidopsis genes, encoding the homologs of pumpkin phloem sap mRNAs, displaying expression in vascular tissues. This tissue-specific expression in Arabidopsis is predicted by the overrepresentation of GA/CT-rich motifs in gene promoters. In this work we have searched for common motifs in upstream regions of the homologous genes from plants considered to possess a "primitive" vascular tissue (a lycophyte), as well as from others that lack a true vascular tissue (a bryophyte), and finally from chlorophytes. Both lycophyte and bryophyte display motifs similar to those found in Arabidopsis with a significantly low E-value, while the chlorophytes showed either a different conserved motif or no conserved motif at all. These results suggest that these same genes are expressed coordinately in non-vascular plants; this coordinate expression may have been one of the prerequisites for the development of conducting tissues in plants. We have also analyzed the phylogeny of conserved proteins that may be involved in phloem function and development. The presence of CmPP16, APL, FT, and YDA in chlorophytes suggests the recruitment of ancient regulatory networks for the development of the vascular tissue during evolution while OPS is a novel protein specific to vascular plants.

No MeSH data available.


Related in: MedlinePlus

Phylogeny of SETPHs in plants. Presence of SETPHs are shown in each taxa. Minus signs refer to absence of orthologs in chlorophytes. YDA, CmPP16, FT and APL are present in chlorophytes and thus can be considered as ancient genes while OPS likely appeared first in Selaginella and is thus considered an innovation.
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Figure 5: Phylogeny of SETPHs in plants. Presence of SETPHs are shown in each taxa. Minus signs refer to absence of orthologs in chlorophytes. YDA, CmPP16, FT and APL are present in chlorophytes and thus can be considered as ancient genes while OPS likely appeared first in Selaginella and is thus considered an innovation.

Mentions: The predicted phylogeny of some key proteins involved in phloem function and differentiation was also analyzed. The results suggest that most dicot and some monocot genes expressed in vascular tissue share GA/CT motifs, as found in Arabidopsis (Ruiz-Medrano et al., 2011). Interestingly, no such motifs were found in chlorophytes, and at least in one of those analyzed, no common motif could be discerned in this gene promoter set. 51 SETPHs were found in chlorophytes but not in all analyzed algal species, suggesting an ancient function of these genes not related with vascular expression (Figure 5, Table 2) Finally, the dendrograms suggest that phloem evolution occurred by the recruitment of preexisting genes involved in certain regulatory networks, as well as the appearance of novel genes altogether.


Vascular gene expression: a hypothesis.

Martínez-Navarro AC, Galván-Gordillo SV, Xoconostle-Cázares B, Ruiz-Medrano R - Front Plant Sci (2013)

Phylogeny of SETPHs in plants. Presence of SETPHs are shown in each taxa. Minus signs refer to absence of orthologs in chlorophytes. YDA, CmPP16, FT and APL are present in chlorophytes and thus can be considered as ancient genes while OPS likely appeared first in Selaginella and is thus considered an innovation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3713349&req=5

Figure 5: Phylogeny of SETPHs in plants. Presence of SETPHs are shown in each taxa. Minus signs refer to absence of orthologs in chlorophytes. YDA, CmPP16, FT and APL are present in chlorophytes and thus can be considered as ancient genes while OPS likely appeared first in Selaginella and is thus considered an innovation.
Mentions: The predicted phylogeny of some key proteins involved in phloem function and differentiation was also analyzed. The results suggest that most dicot and some monocot genes expressed in vascular tissue share GA/CT motifs, as found in Arabidopsis (Ruiz-Medrano et al., 2011). Interestingly, no such motifs were found in chlorophytes, and at least in one of those analyzed, no common motif could be discerned in this gene promoter set. 51 SETPHs were found in chlorophytes but not in all analyzed algal species, suggesting an ancient function of these genes not related with vascular expression (Figure 5, Table 2) Finally, the dendrograms suggest that phloem evolution occurred by the recruitment of preexisting genes involved in certain regulatory networks, as well as the appearance of novel genes altogether.

Bottom Line: Both lycophyte and bryophyte display motifs similar to those found in Arabidopsis with a significantly low E-value, while the chlorophytes showed either a different conserved motif or no conserved motif at all.These results suggest that these same genes are expressed coordinately in non-vascular plants; this coordinate expression may have been one of the prerequisites for the development of conducting tissues in plants.The presence of CmPP16, APL, FT, and YDA in chlorophytes suggests the recruitment of ancient regulatory networks for the development of the vascular tissue during evolution while OPS is a novel protein specific to vascular plants.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology and Bioengineering, CINVESTAV-IPN Mexico DF, Mexico.

ABSTRACT
The phloem is the conduit through which photoassimilates are distributed from autotrophic to heterotrophic tissues and is involved in the distribution of signaling molecules that coordinate plant growth and responses to the environment. Phloem function depends on the coordinate expression of a large array of genes. We have previously identified conserved motifs in upstream regions of the Arabidopsis genes, encoding the homologs of pumpkin phloem sap mRNAs, displaying expression in vascular tissues. This tissue-specific expression in Arabidopsis is predicted by the overrepresentation of GA/CT-rich motifs in gene promoters. In this work we have searched for common motifs in upstream regions of the homologous genes from plants considered to possess a "primitive" vascular tissue (a lycophyte), as well as from others that lack a true vascular tissue (a bryophyte), and finally from chlorophytes. Both lycophyte and bryophyte display motifs similar to those found in Arabidopsis with a significantly low E-value, while the chlorophytes showed either a different conserved motif or no conserved motif at all. These results suggest that these same genes are expressed coordinately in non-vascular plants; this coordinate expression may have been one of the prerequisites for the development of conducting tissues in plants. We have also analyzed the phylogeny of conserved proteins that may be involved in phloem function and development. The presence of CmPP16, APL, FT, and YDA in chlorophytes suggests the recruitment of ancient regulatory networks for the development of the vascular tissue during evolution while OPS is a novel protein specific to vascular plants.

No MeSH data available.


Related in: MedlinePlus