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Silencing of StKCS6 in potato periderm leads to reduced chain lengths of suberin and wax compounds and increased peridermal transpiration.

Serra O, Soler M, Hohn C, Franke R, Schreiber L, Prat S, Molinas M, Figueras M - J. Exp. Bot. (2008)

Bottom Line: All compounds with chain lengths of C(28) and higher were significantly reduced in silenced periderms, whereas compounds with chain lengths of C(26) and lower accumulated.As a result, peridermal transpiration of the silenced lines was about 1.5-times higher than that of the wild type.Our results convincingly show that StKCS6 is involved in both suberin and wax biosynthesis and that a reduction of the monomeric carbon chain lengths leads to increased rates of peridermal transpiration.

View Article: PubMed Central - PubMed

Affiliation: Laboratori del Suro, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Campus Montilivi s/n, E-17071 Girona, Spain.

ABSTRACT
Very long chain aliphatic compounds occur in the suberin polymer and associated wax. Up to now only few genes involved in suberin biosynthesis have been identified. This is a report on the isolation of a potato (Solanum tuberosum) 3-ketoacyl-CoA synthase (KCS) gene and the study of its molecular and physiological relevance by means of a reverse genetic approach. This gene, called StKCS6, was stably silenced by RNA interference (RNAi) in potato. Analysis of the chemical composition of silenced potato tuber periderms indicated that StKCS6 down-regulation has a significant and fairly specific effect on the chain length distribution of very long-chain fatty acids (VLCFAs) and derivatives, occurring in the suberin polymer and peridermal wax. All compounds with chain lengths of C(28) and higher were significantly reduced in silenced periderms, whereas compounds with chain lengths of C(26) and lower accumulated. Thus, StKCS6 is preferentially involved in the formation of suberin and wax lipidic monomers with chain lengths of C(28) and higher. As a result, peridermal transpiration of the silenced lines was about 1.5-times higher than that of the wild type. Our results convincingly show that StKCS6 is involved in both suberin and wax biosynthesis and that a reduction of the monomeric carbon chain lengths leads to increased rates of peridermal transpiration.

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Chemical composition of suberin and wax fractions of StKCS6-RNAi and wild-type periderms from 21-d-stored tubers. (A) Absolute amounts (μg cm−2) of suberin monomers released after trans-esterification of wax-free periderms. (B) Absolute amounts (μg cm−2) of wax compounds obtained by treating the enzymatically isolated periderms with a mixture of chloroform:methanol. StKCS6-RNAi periderms show a decrease in C28 and longer VLCFA and derivatives of all substance classes, both in suberin and wax. Data represent the mean ±sd of the periderms from StKCS6-RNAi (suberin n=8: line 5 n=3, line 9 n=2, line 34 n=3; wax n=7: line 5 n=3, line 9 n=2, line 34 n=2) and wild-type (suberin n = 5; wax n=7) tubers.
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fig3: Chemical composition of suberin and wax fractions of StKCS6-RNAi and wild-type periderms from 21-d-stored tubers. (A) Absolute amounts (μg cm−2) of suberin monomers released after trans-esterification of wax-free periderms. (B) Absolute amounts (μg cm−2) of wax compounds obtained by treating the enzymatically isolated periderms with a mixture of chloroform:methanol. StKCS6-RNAi periderms show a decrease in C28 and longer VLCFA and derivatives of all substance classes, both in suberin and wax. Data represent the mean ±sd of the periderms from StKCS6-RNAi (suberin n=8: line 5 n=3, line 9 n=2, line 34 n=3; wax n=7: line 5 n=3, line 9 n=2, line 34 n=2) and wild-type (suberin n = 5; wax n=7) tubers.

Mentions: Analysis of chemical composition of the aliphatic suberin and wax fractions from 21-d-stored tubers showed that StKCS6 down-regulation results in a significant reduction of the lipid chain lengths (Fig. 3). Both, aliphatic suberin monomers (Fig. 3A) and wax constituents (Fig. 3B) displayed a reduction in compounds with chain length C28 and higher and a concomitant accumulation of those with chain length C26 and lower. For C25 alkane, the large variation observed in wild-type tubers hampers appreciating the effect of StKCS6 silencing, but the accumulation of this compound in StKCS6-silenced periderm was clearly observed in freshly-harvested periderm (see Supplementary Fig. S2 at JXB online) and in 60-d-stored tubers (not shown). Plotting the chain length distribution of all added compounds of the same chain length (Fig. 4) also plainly shows the impact of StKCS6 down-regulation on the shortening of chain length in the suberin and wax lipid profiles. Similar effects of StKCS6 silencing on wax and suberin chemical composition were observed in periderms isolated from freshly-harvested tubers (see Supplementary Fig. S2 and Fig. S3 at JXB online).


Silencing of StKCS6 in potato periderm leads to reduced chain lengths of suberin and wax compounds and increased peridermal transpiration.

Serra O, Soler M, Hohn C, Franke R, Schreiber L, Prat S, Molinas M, Figueras M - J. Exp. Bot. (2008)

Chemical composition of suberin and wax fractions of StKCS6-RNAi and wild-type periderms from 21-d-stored tubers. (A) Absolute amounts (μg cm−2) of suberin monomers released after trans-esterification of wax-free periderms. (B) Absolute amounts (μg cm−2) of wax compounds obtained by treating the enzymatically isolated periderms with a mixture of chloroform:methanol. StKCS6-RNAi periderms show a decrease in C28 and longer VLCFA and derivatives of all substance classes, both in suberin and wax. Data represent the mean ±sd of the periderms from StKCS6-RNAi (suberin n=8: line 5 n=3, line 9 n=2, line 34 n=3; wax n=7: line 5 n=3, line 9 n=2, line 34 n=2) and wild-type (suberin n = 5; wax n=7) tubers.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2651458&req=5

fig3: Chemical composition of suberin and wax fractions of StKCS6-RNAi and wild-type periderms from 21-d-stored tubers. (A) Absolute amounts (μg cm−2) of suberin monomers released after trans-esterification of wax-free periderms. (B) Absolute amounts (μg cm−2) of wax compounds obtained by treating the enzymatically isolated periderms with a mixture of chloroform:methanol. StKCS6-RNAi periderms show a decrease in C28 and longer VLCFA and derivatives of all substance classes, both in suberin and wax. Data represent the mean ±sd of the periderms from StKCS6-RNAi (suberin n=8: line 5 n=3, line 9 n=2, line 34 n=3; wax n=7: line 5 n=3, line 9 n=2, line 34 n=2) and wild-type (suberin n = 5; wax n=7) tubers.
Mentions: Analysis of chemical composition of the aliphatic suberin and wax fractions from 21-d-stored tubers showed that StKCS6 down-regulation results in a significant reduction of the lipid chain lengths (Fig. 3). Both, aliphatic suberin monomers (Fig. 3A) and wax constituents (Fig. 3B) displayed a reduction in compounds with chain length C28 and higher and a concomitant accumulation of those with chain length C26 and lower. For C25 alkane, the large variation observed in wild-type tubers hampers appreciating the effect of StKCS6 silencing, but the accumulation of this compound in StKCS6-silenced periderm was clearly observed in freshly-harvested periderm (see Supplementary Fig. S2 at JXB online) and in 60-d-stored tubers (not shown). Plotting the chain length distribution of all added compounds of the same chain length (Fig. 4) also plainly shows the impact of StKCS6 down-regulation on the shortening of chain length in the suberin and wax lipid profiles. Similar effects of StKCS6 silencing on wax and suberin chemical composition were observed in periderms isolated from freshly-harvested tubers (see Supplementary Fig. S2 and Fig. S3 at JXB online).

Bottom Line: All compounds with chain lengths of C(28) and higher were significantly reduced in silenced periderms, whereas compounds with chain lengths of C(26) and lower accumulated.As a result, peridermal transpiration of the silenced lines was about 1.5-times higher than that of the wild type.Our results convincingly show that StKCS6 is involved in both suberin and wax biosynthesis and that a reduction of the monomeric carbon chain lengths leads to increased rates of peridermal transpiration.

View Article: PubMed Central - PubMed

Affiliation: Laboratori del Suro, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Campus Montilivi s/n, E-17071 Girona, Spain.

ABSTRACT
Very long chain aliphatic compounds occur in the suberin polymer and associated wax. Up to now only few genes involved in suberin biosynthesis have been identified. This is a report on the isolation of a potato (Solanum tuberosum) 3-ketoacyl-CoA synthase (KCS) gene and the study of its molecular and physiological relevance by means of a reverse genetic approach. This gene, called StKCS6, was stably silenced by RNA interference (RNAi) in potato. Analysis of the chemical composition of silenced potato tuber periderms indicated that StKCS6 down-regulation has a significant and fairly specific effect on the chain length distribution of very long-chain fatty acids (VLCFAs) and derivatives, occurring in the suberin polymer and peridermal wax. All compounds with chain lengths of C(28) and higher were significantly reduced in silenced periderms, whereas compounds with chain lengths of C(26) and lower accumulated. Thus, StKCS6 is preferentially involved in the formation of suberin and wax lipidic monomers with chain lengths of C(28) and higher. As a result, peridermal transpiration of the silenced lines was about 1.5-times higher than that of the wild type. Our results convincingly show that StKCS6 is involved in both suberin and wax biosynthesis and that a reduction of the monomeric carbon chain lengths leads to increased rates of peridermal transpiration.

Show MeSH