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Phenolic compounds and expression of 4CL genes in silver birch clones and Pt4CL1a lines.

Sutela S, Hahl T, Tiimonen H, Aronen T, Ylioja T, Laakso T, Saranpää P, Chiang V, Julkunen-Tiitto R, Häggman H - PLoS ONE (2014)

Bottom Line: However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones.The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified.However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Oulu, Oulu, Finland.

ABSTRACT
A small multigene family encodes 4-coumarate:CoA ligases (4CLs) catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1) to the lignin and soluble phenolic compound composition of silver birch (Betula pendula) Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S) and guaiacyl (G) lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1) were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.

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Phylogenetic analysis of silver birch (Betula pendula) 4CL and 4CL-like sequences.ML tree was constructed using the cds of silver birch putative 4CL (Bp4CL1, Bp4CL2, Bp4CL4) genes and 4CL-like (Bp4CL3) gene.
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pone-0114434-g001: Phylogenetic analysis of silver birch (Betula pendula) 4CL and 4CL-like sequences.ML tree was constructed using the cds of silver birch putative 4CL (Bp4CL1, Bp4CL2, Bp4CL4) genes and 4CL-like (Bp4CL3) gene.

Mentions: Four putative 4CL-like mRNA sequences, Bp4CL1-4, were obtained from clone A and submitted to the GenBank with accession numbers KM099195-8. The alignments of predicted amino acid sequences of Bp4CL1-4 are shown in S10-S13 Figures in S1 File. The 1629 bp long cds of Bp4CL1 was 99% similar to the 4CL sequences of B. platyphylla (AY792353) and B. luminifera (FJ410448). Furthermore, the predicted amino acid sequence of Bp4CL1 was identical with the translated 4CL sequence of B. platyphylla. At nucleotide level the 1725 bp long cds of Bp4CL2 showed highest similarity (81%) with the predicted 4CL mRNA of Malus x domestica (XM_008378682). At amino acid level the 4CL sequence of Theobroma cacao (XP_007029575) showed highest identity (84%) with predicted amino acid sequence of Bp4CL1. The cds of Bp4CL3, 1638 bp in length, showed 76% identity with 4CL-like sequence of Malus x domestica (XM_008386493) at nucleotide level and 79% similarity with the AMP dependent CoA ligase of Ricinus communis (XP_002523698) at amino acid level. The 1629 bp long cds of Bp4CL4 showed 79% similarity with Eriobotrya japonica 4CL sequence (KF767458) and 85% similarity at amino acid level with the Fragaria vesca subsp. vesca 4CL-like sequence (XP_004309949). The phylogenetic analysis was conducted for the classification of 4CLs using a partial set of 4CL-like ACS sequences presented by de Azevedo Souza et al.[23] supplemented with cds of M. esculenta, G. max, R. communis, R. idaeus, P. tremuloides, B. platyphylla and B. luminifera 4CLs (S5 Table in S3 File). The phylogenetic analysis suggested that Bp4CL1 and Bp4CL4 would belong to class I and Bp4CL2 to class II 4CLs (Fig. 1). The fourth 4CL sequence, Bp4CL3, would belong to the group of 4CL-like ACS.


Phenolic compounds and expression of 4CL genes in silver birch clones and Pt4CL1a lines.

Sutela S, Hahl T, Tiimonen H, Aronen T, Ylioja T, Laakso T, Saranpää P, Chiang V, Julkunen-Tiitto R, Häggman H - PLoS ONE (2014)

Phylogenetic analysis of silver birch (Betula pendula) 4CL and 4CL-like sequences.ML tree was constructed using the cds of silver birch putative 4CL (Bp4CL1, Bp4CL2, Bp4CL4) genes and 4CL-like (Bp4CL3) gene.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263613&req=5

pone-0114434-g001: Phylogenetic analysis of silver birch (Betula pendula) 4CL and 4CL-like sequences.ML tree was constructed using the cds of silver birch putative 4CL (Bp4CL1, Bp4CL2, Bp4CL4) genes and 4CL-like (Bp4CL3) gene.
Mentions: Four putative 4CL-like mRNA sequences, Bp4CL1-4, were obtained from clone A and submitted to the GenBank with accession numbers KM099195-8. The alignments of predicted amino acid sequences of Bp4CL1-4 are shown in S10-S13 Figures in S1 File. The 1629 bp long cds of Bp4CL1 was 99% similar to the 4CL sequences of B. platyphylla (AY792353) and B. luminifera (FJ410448). Furthermore, the predicted amino acid sequence of Bp4CL1 was identical with the translated 4CL sequence of B. platyphylla. At nucleotide level the 1725 bp long cds of Bp4CL2 showed highest similarity (81%) with the predicted 4CL mRNA of Malus x domestica (XM_008378682). At amino acid level the 4CL sequence of Theobroma cacao (XP_007029575) showed highest identity (84%) with predicted amino acid sequence of Bp4CL1. The cds of Bp4CL3, 1638 bp in length, showed 76% identity with 4CL-like sequence of Malus x domestica (XM_008386493) at nucleotide level and 79% similarity with the AMP dependent CoA ligase of Ricinus communis (XP_002523698) at amino acid level. The 1629 bp long cds of Bp4CL4 showed 79% similarity with Eriobotrya japonica 4CL sequence (KF767458) and 85% similarity at amino acid level with the Fragaria vesca subsp. vesca 4CL-like sequence (XP_004309949). The phylogenetic analysis was conducted for the classification of 4CLs using a partial set of 4CL-like ACS sequences presented by de Azevedo Souza et al.[23] supplemented with cds of M. esculenta, G. max, R. communis, R. idaeus, P. tremuloides, B. platyphylla and B. luminifera 4CLs (S5 Table in S3 File). The phylogenetic analysis suggested that Bp4CL1 and Bp4CL4 would belong to class I and Bp4CL2 to class II 4CLs (Fig. 1). The fourth 4CL sequence, Bp4CL3, would belong to the group of 4CL-like ACS.

Bottom Line: However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones.The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified.However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Oulu, Oulu, Finland.

ABSTRACT
A small multigene family encodes 4-coumarate:CoA ligases (4CLs) catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1) to the lignin and soluble phenolic compound composition of silver birch (Betula pendula) Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S) and guaiacyl (G) lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1) were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.

Show MeSH
Related in: MedlinePlus