An engineered sorbitol cycle alters sugar composition, not growth, in transformed tobacco

Michihito Deguchi, Alan B. Bennett, Shohei Yamaki, Kunio Yamada, Koki Kanahama, Yoshinori Kanayama

    Research output: Contribution to journalArticlepeer-review

    17 Citations (Scopus)


    Many efforts have been made to engineer stress tolerance by accumulating polyols. Transformants that accumulate polyols often show growth inhibition, because polyols are synthesized as a dead-end product in plants that do not naturally accumulate polyols. Here, we show a novel strategy in which a sorbitol cycle was engineered by introducing apple cDNA encoding NAD-dependent sorbitol dehydrogenase (SDH) in addition to sorbitol-6-phosphate dehydrogenase (S6PDH). Tobacco plants transformed only with S6PDH showed growth inhibition, and very few transformants were obtained. In contrast, many transgenic plants with both S6PDH and SDH were easily obtained, and their growth was normal despite their accumulation of sorbitol. Interestingly, the engineered sorbitol cycle enhanced the accumulation of sucrose instead of fructose that was expected to be increased. Sucrose, rather than fructose, was also increased in the immature fruit of tomato plants transformed with an antisense fructokinase gene in which the phosphorylation of fructose was inhibited. A common phenomenon was observed in the metabolic engineering of two different pathways, showing the presence of homeostatic regulation of fructose levels.

    Original languageEnglish
    Pages (from-to)1980-1988
    Number of pages9
    JournalPlant, Cell and Environment
    Issue number10
    Publication statusPublished - 2006 Oct 1


    • Polyol
    • Sorbitol dehydrogenase
    • Sorbitol-6-phosphate dehydrogenase
    • Sucrose

    ASJC Scopus subject areas

    • Physiology
    • Plant Science


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