Expression of stearate and oleate desaturases in normal and high oleic acid sunflower, cloning of genomic fragments and variability in different Helianthus.
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Steady state levels of transcript, detected with heterologous probes to either the DELTA9 desaturase [stearoyl-CoA desaturase] or the DELTA12 desaturase [phosphatidylcholine desaturase], were determined in immature seeds and vegetative tissues of sunflower at different stages. The transcripts of the DELTA9 and the DELTA12 genes were mainly detected in immature embryos between 12 and 20 days after pollination, and weakly in the other tissues examined. The accumulation of DELTA9 gene transcript preceded that of the DELTA12 gene, and coincided with the onset of detectable enzyme activities. The levels of mRNA accumulation in CANP3, a line with normal levels of oleic acid, and a high oleic acid line (HOC) were compared after standardization of signal intensities. The DELTA12 mRNA accumulation was significantly reduced in HOC compared to CANP3. In HOC varieties, DELTA12 enzyme activity is considerably reduced in seeds but maintained in leaves. It is suggested that the HOC mutation is correlated with areduction in the steady state level of a putative seed specific DELTA12 gene. It was also observed that the DELTA9 and DELTA12 mRNAs accumulated to higher levels in developing seeds maintained at 26C day/22C night than at 20C day/18C night. From a genomic library, 2 and 4 clones carrying sequences homologous to the DELTA9 and DELTA12 desaturases, respectively, were used for amplification with primers unique to each desaturase. This enabled the desaturases to be clearly identified. Moreover, the couple of primers unique to the DELTA9 desaturase were used to amplify fragments in 12 wild species covering most of the genus Helianthus. Sequence variability revealed a mixture of 2 DELTA9 sequences in all the species.
Incluye 37 referencias bibliográficas.
Steady state levels of transcript, detected with heterologous probes to either the DELTA9 desaturase [stearoyl-CoA desaturase] or the DELTA12 desaturase [phosphatidylcholine desaturase], were determined in immature seeds and vegetative tissues of sunflower at different stages. The transcripts of the DELTA9 and the DELTA12 genes were mainly detected in immature embryos between 12 and 20 days after pollination, and weakly in the other tissues examined. The accumulation of DELTA9 gene transcript preceded that of the DELTA12 gene, and coincided with the onset of detectable enzyme activities. The levels of mRNA accumulation in CANP3, a line with normal levels of oleic acid, and a high oleic acid line (HOC) were compared after standardization of signal intensities. The DELTA12 mRNA accumulation was significantly reduced in HOC compared to CANP3. In HOC varieties, DELTA12 enzyme activity is considerably reduced in seeds but maintained in leaves. It is suggested that the HOC mutation is correlated with areduction in the steady state level of a putative seed specific DELTA12 gene. It was also observed that the DELTA9 and DELTA12 mRNAs accumulated to higher levels in developing seeds maintained at 26C day/22C night than at 20C day/18C night. From a genomic library, 2 and 4 clones carrying sequences homologous to the DELTA9 and DELTA12 desaturases, respectively, were used for amplification with primers unique to each desaturase. This enabled the desaturases to be clearly identified. Moreover, the couple of primers unique to the DELTA9 desaturase were used to amplify fragments in 12 wild species covering most of the genus Helianthus. Sequence variability revealed a mixture of 2 DELTA9 sequences in all the species.
Incluye 37 referencias bibliográficas.
Steady state levels of transcript, detected with heterologous probes to either the DELTA9 desaturase [stearoyl-CoA desaturase] or the DELTA12 desaturase [phosphatidylcholine desaturase], were determined in immature seeds and vegetative tissues of sunflower at different stages. The transcripts of the DELTA9 and the DELTA12 genes were mainly detected in immature embryos between 12 and 20 days after pollination, and weakly in the other tissues examined. The accumulation of DELTA9 gene transcript preceded that of the DELTA12 gene, and coincided with the onset of detectable enzyme activities. The levels of mRNA accumulation in CANP3, a line with normal levels of oleic acid, and a high oleic acid line (HOC) were compared after standardization of signal intensities. The DELTA12 mRNA accumulation was significantly reduced in HOC compared to CANP3. In HOC varieties, DELTA12 enzyme activity is considerably reduced in seeds but maintained in leaves. It is suggested that the HOC mutation is correlated with areduction in the steady state level of a putative seed specific DELTA12 gene. It was also observed that the DELTA9 and DELTA12 mRNAs accumulated to higher levels in developing seeds maintained at 26C day/22C night than at 20C day/18C night. From a genomic library, 2 and 4 clones carrying sequences homologous to the DELTA9 and DELTA12 desaturases, respectively, were used for amplification with primers unique to each desaturase. This enabled the desaturases to be clearly identified. Moreover, the couple of primers unique to the DELTA9 desaturase were used to amplify fragments in 12 wild species covering most of the genus Helianthus. Sequence variability revealed a mixture of 2 DELTA9 sequences in all the species.
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Ácidos grasos., clonacición, Clones., Enzimas., Genes., Girasol