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Gene expression analysis in cadmium-stressed roots of a low cadmium-accumulating solanaceous plant, Solanum torvum.

Yamaguchi H, Fukuoka H, Arao T, Ohyama A, Nunome T, Miyatake K, Negoro S - J. Exp. Bot. (2009)

Bottom Line: In addition to induction of heavy metal chaperone proteins, antioxidative and sulphur-assimilating enzymes were induced, confirming that oxidative stress developed even using a mild Cd concentration.Rapid repression of dehydration-related transcription factors and aquaporin isoforms suggests that dehydration stress is a potential constituent of Cd-induced biochemical impediments.These transcriptional changes were also confirmed by real-time reverse transcription-PCR.

View Article: PubMed Central - PubMed

Affiliation: Molecular Genetics and Physiology Research Team, National Institute of Vegetable and Tea Science, 360 Kusawa, Ano-cho, Tsu, Mie, Japan. hyamagu@affrc.go.jp

ABSTRACT
Solanum torvum Sw. cv. Torubamubiga (TB) is a low cadmium (Cd)-accumulating plant. To elucidate the molecular mechanisms of the Cd acclimation process in TB roots, transcriptional regulation was analysed in response to mild Cd treatment: 0.1 muM CdCl(2) in hydroponic solution. A unigene set consisting of 6296 unigene sequences was constructed from 18 816 TB cDNAs. The distribution of functional categories was similar to tomato, while 330 unigenes were suggested to be TB specific. For expression profiling, the SuperSAGE method was adapted for use with Illumina sequencing technology. Expression tag libraries were constructed from Cd-treated (for 3 h, 1 d, and 3 d) and untreated roots, and 34 269 species of independent tags were collected. Moreover, 6237 tags were ascribed to the TB or eggplant (aubergine) unigene sequences. Time-course changes were examined, and 2049 up- and 2022 down-regulated tags were identified. Although no tags annotated to metal transporter genes were significantly regulated, a tag annotated to AtFRD3, a xylem-loading citrate transporter, was down-regulated. In addition to induction of heavy metal chaperone proteins, antioxidative and sulphur-assimilating enzymes were induced, confirming that oxidative stress developed even using a mild Cd concentration. Rapid repression of dehydration-related transcription factors and aquaporin isoforms suggests that dehydration stress is a potential constituent of Cd-induced biochemical impediments. These transcriptional changes were also confirmed by real-time reverse transcription-PCR. Further additions of TB unigene sequences and functional analysis of the regulated tags will reveal the molecular basis of the Cd acclimation process, including the low Cd-accumulating characteristics of TB.

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Related in: MedlinePlus

Time-course changes of the expression of the 23 TB unigenes in the roots during Cd treatment. TB plants were hydroponically grown and CdCl2 was added to the culture solutions at a final concentration of 0.1 μM. The roots were harvested 3 h (Cd3h), 1 d (Cd1d), or 3 d (Cd3d) after the start of treatment, together with untreated roots (Cd0). The relative amount of transcripts of individual TB unigenes in the roots was determined by real-time RT-PCR. Expression levels of the unigenes in Cd-treated roots relative to those in untreated roots were calculated using a unigene TVR18P14C (a ubiquitin gene) as a standard control. Bars indicate standard errors (n=4).
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fig7: Time-course changes of the expression of the 23 TB unigenes in the roots during Cd treatment. TB plants were hydroponically grown and CdCl2 was added to the culture solutions at a final concentration of 0.1 μM. The roots were harvested 3 h (Cd3h), 1 d (Cd1d), or 3 d (Cd3d) after the start of treatment, together with untreated roots (Cd0). The relative amount of transcripts of individual TB unigenes in the roots was determined by real-time RT-PCR. Expression levels of the unigenes in Cd-treated roots relative to those in untreated roots were calculated using a unigene TVR18P14C (a ubiquitin gene) as a standard control. Bars indicate standard errors (n=4).

Mentions: A list of the differentially regulated genes expected to be involved in heavy metal metabolism or other responses induced by Cd stress is shown in Table 5. The transcriptional regulation of these genes was also confirmed by real-time RT-PCR (Fig. 7).


Gene expression analysis in cadmium-stressed roots of a low cadmium-accumulating solanaceous plant, Solanum torvum.

Yamaguchi H, Fukuoka H, Arao T, Ohyama A, Nunome T, Miyatake K, Negoro S - J. Exp. Bot. (2009)

Time-course changes of the expression of the 23 TB unigenes in the roots during Cd treatment. TB plants were hydroponically grown and CdCl2 was added to the culture solutions at a final concentration of 0.1 μM. The roots were harvested 3 h (Cd3h), 1 d (Cd1d), or 3 d (Cd3d) after the start of treatment, together with untreated roots (Cd0). The relative amount of transcripts of individual TB unigenes in the roots was determined by real-time RT-PCR. Expression levels of the unigenes in Cd-treated roots relative to those in untreated roots were calculated using a unigene TVR18P14C (a ubiquitin gene) as a standard control. Bars indicate standard errors (n=4).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2803209&req=5

fig7: Time-course changes of the expression of the 23 TB unigenes in the roots during Cd treatment. TB plants were hydroponically grown and CdCl2 was added to the culture solutions at a final concentration of 0.1 μM. The roots were harvested 3 h (Cd3h), 1 d (Cd1d), or 3 d (Cd3d) after the start of treatment, together with untreated roots (Cd0). The relative amount of transcripts of individual TB unigenes in the roots was determined by real-time RT-PCR. Expression levels of the unigenes in Cd-treated roots relative to those in untreated roots were calculated using a unigene TVR18P14C (a ubiquitin gene) as a standard control. Bars indicate standard errors (n=4).
Mentions: A list of the differentially regulated genes expected to be involved in heavy metal metabolism or other responses induced by Cd stress is shown in Table 5. The transcriptional regulation of these genes was also confirmed by real-time RT-PCR (Fig. 7).

Bottom Line: In addition to induction of heavy metal chaperone proteins, antioxidative and sulphur-assimilating enzymes were induced, confirming that oxidative stress developed even using a mild Cd concentration.Rapid repression of dehydration-related transcription factors and aquaporin isoforms suggests that dehydration stress is a potential constituent of Cd-induced biochemical impediments.These transcriptional changes were also confirmed by real-time reverse transcription-PCR.

View Article: PubMed Central - PubMed

Affiliation: Molecular Genetics and Physiology Research Team, National Institute of Vegetable and Tea Science, 360 Kusawa, Ano-cho, Tsu, Mie, Japan. hyamagu@affrc.go.jp

ABSTRACT
Solanum torvum Sw. cv. Torubamubiga (TB) is a low cadmium (Cd)-accumulating plant. To elucidate the molecular mechanisms of the Cd acclimation process in TB roots, transcriptional regulation was analysed in response to mild Cd treatment: 0.1 muM CdCl(2) in hydroponic solution. A unigene set consisting of 6296 unigene sequences was constructed from 18 816 TB cDNAs. The distribution of functional categories was similar to tomato, while 330 unigenes were suggested to be TB specific. For expression profiling, the SuperSAGE method was adapted for use with Illumina sequencing technology. Expression tag libraries were constructed from Cd-treated (for 3 h, 1 d, and 3 d) and untreated roots, and 34 269 species of independent tags were collected. Moreover, 6237 tags were ascribed to the TB or eggplant (aubergine) unigene sequences. Time-course changes were examined, and 2049 up- and 2022 down-regulated tags were identified. Although no tags annotated to metal transporter genes were significantly regulated, a tag annotated to AtFRD3, a xylem-loading citrate transporter, was down-regulated. In addition to induction of heavy metal chaperone proteins, antioxidative and sulphur-assimilating enzymes were induced, confirming that oxidative stress developed even using a mild Cd concentration. Rapid repression of dehydration-related transcription factors and aquaporin isoforms suggests that dehydration stress is a potential constituent of Cd-induced biochemical impediments. These transcriptional changes were also confirmed by real-time reverse transcription-PCR. Further additions of TB unigene sequences and functional analysis of the regulated tags will reveal the molecular basis of the Cd acclimation process, including the low Cd-accumulating characteristics of TB.

Show MeSH
Related in: MedlinePlus