Limits...
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.

Show MeSH

Related in: MedlinePlus

The contents of phenolic compounds and condensed tannins in silver birch (Betula pendula) stems and leaves.Stems (A) and leaves (B) of clones A, E5382, E5396, and R, and Pt4CL1a lines A1, A5 and E5282/3 and nptII line E5396/4. Values are mg/DW g mean ± SE. Different letters above the columns denote significant (P<0.05) difference between the clones. Stars above the columns of transgenic lines denote significant (P<0.05) difference between transgenic line to non-transgenic clone.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4263613&req=5

pone-0114434-g003: The contents of phenolic compounds and condensed tannins in silver birch (Betula pendula) stems and leaves.Stems (A) and leaves (B) of clones A, E5382, E5396, and R, and Pt4CL1a lines A1, A5 and E5282/3 and nptII line E5396/4. Values are mg/DW g mean ± SE. Different letters above the columns denote significant (P<0.05) difference between the clones. Stars above the columns of transgenic lines denote significant (P<0.05) difference between transgenic line to non-transgenic clone.

Mentions: The cinnamic acid derivative content of clone A stems was prominent (Fig. 3A, S9 Table in S5 File). Two cinnamic acid derivatives were detected as trace amounts in clone A, but instead the concentration of p-OH-cinnamic acid glucoside was at highest level, resulting in significantly (P<0.05) higher total content of cinnamic acids. In stems of clone E5396, the content of p-OH-cinnamic acid glucoside was significantly (P<0.05) higher than in clones E5382 and R, and also a significant difference was found between clones E5382 and E5396 in the content of total cinnamic acid derivatives. Of individual flavonoids the concentration of a myricetin derivative was significantly (P<0.05) lower in clone A than clone R, however, the total flavonoid concentrations were similar in all studied clones (Fig. 3A). The total phenolic glycoside content was greatest in clone E5396 caused by the high platyfylloside content, however, the differences were significant only between clones E5396 and E5382. The salidroside content of stems was significantly lower in clone A than in the clones E5382 and R (S9 Table in S5 File).


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)

The contents of phenolic compounds and condensed tannins in silver birch (Betula pendula) stems and leaves.Stems (A) and leaves (B) of clones A, E5382, E5396, and R, and Pt4CL1a lines A1, A5 and E5282/3 and nptII line E5396/4. Values are mg/DW g mean ± SE. Different letters above the columns denote significant (P<0.05) difference between the clones. Stars above the columns of transgenic lines denote significant (P<0.05) difference between transgenic line to non-transgenic clone.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114434-g003: The contents of phenolic compounds and condensed tannins in silver birch (Betula pendula) stems and leaves.Stems (A) and leaves (B) of clones A, E5382, E5396, and R, and Pt4CL1a lines A1, A5 and E5282/3 and nptII line E5396/4. Values are mg/DW g mean ± SE. Different letters above the columns denote significant (P<0.05) difference between the clones. Stars above the columns of transgenic lines denote significant (P<0.05) difference between transgenic line to non-transgenic clone.
Mentions: The cinnamic acid derivative content of clone A stems was prominent (Fig. 3A, S9 Table in S5 File). Two cinnamic acid derivatives were detected as trace amounts in clone A, but instead the concentration of p-OH-cinnamic acid glucoside was at highest level, resulting in significantly (P<0.05) higher total content of cinnamic acids. In stems of clone E5396, the content of p-OH-cinnamic acid glucoside was significantly (P<0.05) higher than in clones E5382 and R, and also a significant difference was found between clones E5382 and E5396 in the content of total cinnamic acid derivatives. Of individual flavonoids the concentration of a myricetin derivative was significantly (P<0.05) lower in clone A than clone R, however, the total flavonoid concentrations were similar in all studied clones (Fig. 3A). The total phenolic glycoside content was greatest in clone E5396 caused by the high platyfylloside content, however, the differences were significant only between clones E5396 and E5382. The salidroside content of stems was significantly lower in clone A than in the clones E5382 and R (S9 Table in S5 File).

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