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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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StKCS6 transcript profile in potato organs and tuber tissues and its down-regulation in StKCS6-silenced lines. (A) Relative StKCS6 transcript accumulation (log-transformed) in potato stem (S), leaf (L), root (R), tuber-parenchyma (T-PAR), and tuber periderm (T-PER) was determined by real-time RT-PCR analysis. Values were normalized using the housekeeping reference gene adenine phosphoribosyl transferase. The data represent the mean ±sd of three replicates. (B) RT-PCR analysis with PCR incremental cycle numbers of the StKCS6 gene, to verify silencing of the StKCS6 transcript. Samples correspond to potato tuber periderms of independent StKCS6-RNAi transgenic lines. PCR products were analysed at the cycle numbers indicated in the top. Equal amount of cDNA was used as template for each sample as showed by the PCR amplification of StACTIN. Note that lines 5, 9, and 34 showed the highest StKCS6 down-regulation whereas line 23 was partially silenced and line 37 was non-silenced, showing an accumulation of the StKCS6 transcript comparable to that of the wild type.
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fig1: StKCS6 transcript profile in potato organs and tuber tissues and its down-regulation in StKCS6-silenced lines. (A) Relative StKCS6 transcript accumulation (log-transformed) in potato stem (S), leaf (L), root (R), tuber-parenchyma (T-PAR), and tuber periderm (T-PER) was determined by real-time RT-PCR analysis. Values were normalized using the housekeeping reference gene adenine phosphoribosyl transferase. The data represent the mean ±sd of three replicates. (B) RT-PCR analysis with PCR incremental cycle numbers of the StKCS6 gene, to verify silencing of the StKCS6 transcript. Samples correspond to potato tuber periderms of independent StKCS6-RNAi transgenic lines. PCR products were analysed at the cycle numbers indicated in the top. Equal amount of cDNA was used as template for each sample as showed by the PCR amplification of StACTIN. Note that lines 5, 9, and 34 showed the highest StKCS6 down-regulation whereas line 23 was partially silenced and line 37 was non-silenced, showing an accumulation of the StKCS6 transcript comparable to that of the wild type.

Mentions: To examine the StKCS6 expression profile, StKCS6 transcript levels in different organs of potato were analysed by real-time PCR (Fig. 1A). StKCS6 expression was highest in the tuber periderm. Lower but still significant expression levels could be detected in the leaf, stem, and root, but not in the parenchyma of tubers.


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)

StKCS6 transcript profile in potato organs and tuber tissues and its down-regulation in StKCS6-silenced lines. (A) Relative StKCS6 transcript accumulation (log-transformed) in potato stem (S), leaf (L), root (R), tuber-parenchyma (T-PAR), and tuber periderm (T-PER) was determined by real-time RT-PCR analysis. Values were normalized using the housekeeping reference gene adenine phosphoribosyl transferase. The data represent the mean ±sd of three replicates. (B) RT-PCR analysis with PCR incremental cycle numbers of the StKCS6 gene, to verify silencing of the StKCS6 transcript. Samples correspond to potato tuber periderms of independent StKCS6-RNAi transgenic lines. PCR products were analysed at the cycle numbers indicated in the top. Equal amount of cDNA was used as template for each sample as showed by the PCR amplification of StACTIN. Note that lines 5, 9, and 34 showed the highest StKCS6 down-regulation whereas line 23 was partially silenced and line 37 was non-silenced, showing an accumulation of the StKCS6 transcript comparable to that of the wild type.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: StKCS6 transcript profile in potato organs and tuber tissues and its down-regulation in StKCS6-silenced lines. (A) Relative StKCS6 transcript accumulation (log-transformed) in potato stem (S), leaf (L), root (R), tuber-parenchyma (T-PAR), and tuber periderm (T-PER) was determined by real-time RT-PCR analysis. Values were normalized using the housekeeping reference gene adenine phosphoribosyl transferase. The data represent the mean ±sd of three replicates. (B) RT-PCR analysis with PCR incremental cycle numbers of the StKCS6 gene, to verify silencing of the StKCS6 transcript. Samples correspond to potato tuber periderms of independent StKCS6-RNAi transgenic lines. PCR products were analysed at the cycle numbers indicated in the top. Equal amount of cDNA was used as template for each sample as showed by the PCR amplification of StACTIN. Note that lines 5, 9, and 34 showed the highest StKCS6 down-regulation whereas line 23 was partially silenced and line 37 was non-silenced, showing an accumulation of the StKCS6 transcript comparable to that of the wild type.
Mentions: To examine the StKCS6 expression profile, StKCS6 transcript levels in different organs of potato were analysed by real-time PCR (Fig. 1A). StKCS6 expression was highest in the tuber periderm. Lower but still significant expression levels could be detected in the leaf, stem, and root, but not in the parenchyma of tubers.

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