Increase in sorbitol biosynthesis in stressed Japanese pear leaves

M. Deguchi, M. Watanabe, Y. Kanayama

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    8 Citations (Scopus)


    To clarify the mechanism of stress response in leaf tissue of Japanese pear, sugar content, conversion from glucose to sorbitol, and S6PDH mRNA expression were investigated in leaf discs incubated under salt or low temperature stress. Sorbitol contents increased in the leaf discs under both stresses. The recovery of 14C in sorbitol also increased in the leaf discs incubated with 14C-glucose under both stresses. Glucose, fructose, and sucrose content also increased in the leaf discs although the recoveries of 14C in those sugars in the leaf discs did not change. The result suggests that Japanese pear leaves respond to salt and low temperature stress and dominantly synthesize sorbitol. Next, the PCR fragment of putative S6PDH cDNA was cloned by RT-PCR from Japanese pear leaves because sorbitol-6-phosphate dehydrogenase (S6PDH) could be a key enzyme in sorbitol biosynthesis as described in apple. The nucleotide sequence was identical to 98% S6PDH cDNA from apple seedlings. Northern blot analysis suggested that S6PDH mRNA expression was source-specific and was induced by salt and low temperature stress. Collectively, sorbitol accumulation is induced by salt and low temperature stress, and the accumulation is probably due to an increase in sorbitol biosynthesis that is related to the expression of S6PDH gene.

    Original languageEnglish
    Title of host publicationInternational Symposium on Asian Pears, Commemorating the 100th Anniversary of Nijisseiki Pear
    PublisherInternational Society for Horticultural Science
    Number of pages7
    ISBN (Print)9789066057661
    Publication statusPublished - 2002 Jan 1

    Publication series

    NameActa Horticulturae
    ISSN (Print)0567-7572


    • Cold hardiness
    • Sorbitol-6-phosphate dehydrogenase
    • Sugar
    • Sugar alcohol

    ASJC Scopus subject areas

    • Horticulture


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