Overexpression of dehydroascorbate reductase, but not monodehydroascorbate reductase, confers tolerance to Aluminum stress in transgenic Tobacco

Lina Yin, Shiwen Wang, Amin Elsadig Eltayeb, Md Imtiaz Uddin, Yoko Yamamoto, Wataru Tsuji, Yuichi Takeuchi, Kiyoshi Tanaka

    Research output: Contribution to journalArticlepeer-review

    175 Citations (Scopus)

    Abstract

    Aluminum (Al) inhibits plant growth partly by causing oxidative damage that is promoted by reactive oxygen species and can be prevented by improving antioxidant capacity. Ascorbic acid (AsA), the most abundant antioxidant in plants, is regenerated by the action of monodehydroascorbate reductase (MDAR) and dehydroascorbate reductase (DHAR). We investigated the role of MDAR and DHAR in AsA regeneration during Al stress using transgenic tobacco (Nicotiana tabacum) plants overexpressing Arabidopsis cytosolic MDAR (MDAR-OX) or DHAR (DHAR-OX). DHAR-OX plants showed better root growth than wild-type (SR-1) plants after exposure to Al for 2 weeks, but MDAR-OX plants did not. There was no difference in Al distribution and accumulation in the root tips among SR-1, DHAR-OX, and MDAR-OX plants after Al treatment for 24 h. However, DHAR-OX plants showed lower hydrogen peroxide content, less lipid peroxidation and lower level of oxidative DNA damage than SR-1 plants, whereas MDAR-OX plants showed the same extent of damage as SR-1 plants. Compared with SR-1 plants, DHAR-OX plants consistently maintained a higher AsA level both with and without Al exposure, while MDAR-OX plants maintained a higher AsA level only without Al exposure. Also, DHAR-OX plants maintained higher APX activity under Al stress. The higher AsA level and APX activity in DHAR-OX plants contributed to their higher antioxidant capacity and higher tolerance to Al stress. These findings show that the overexpression of DHAR, but not of MDAR, confers Al tolerance, and that maintenance of a high AsA level is important to Al tolerance.

    Original languageEnglish
    Pages (from-to)609-621
    Number of pages13
    JournalPlanta
    Volume231
    Issue number3
    DOIs
    Publication statusPublished - Jan 2010

    Keywords

    • Al tolerance
    • Aluminum
    • Ascorbic acid
    • Dehydroascorbate reductase
    • Monodehydroascorbate reductase
    • Reactive oxygen species

    ASJC Scopus subject areas

    • Genetics
    • Plant Science

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