Effect of indole-3-acetic acid on aluminum-induced efflux of malic acid from wheat (Triticum aestivum L.)

• Published in: Plant and soil 2011-09, Vol.346 (1/2), p.215-230, Article 215
• Main Authors: Yang, Ye, Wang, Qiao Lan, Geng, Ming Jian, Guo, Zai Hua, Zhao, Zhuqing
• Format: Article
• Language: English
• Subjects: Acetic acid; Acid soils; Acidic soils; Acids; Agronomy. Soil science and plant productions; Aluminum; Animal, plant and microbial ecology; Anions; Anthracene; Auxin; Biological and medical sciences; Biomedical and Life Sciences; Carboxylic acids; Ecology; Environmental stress; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Hydroponics; Insulin antibodies; Life Sciences; Malic acid; Organic acids; Oxidases; Plant Physiology; Plant resistance; Plant roots; Plant Sciences; Plants; Regular Article; Secretion; Seedlings; Soil acidity; Soil Science & Conservation; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Triticum aestivum; Wheat
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-011-0811-1

Indole-3-acetic acid (IAA) has been found to be involved in plant resistance to various types of environmental stress. Aluminum (Al) toxicity, as one of the most important environmental stress in acid soils, is coped by most plants through the efflux of organic acids via anion channel. This study aims to evaluate the effect of IAA on efflux of malic acid from wheat (Triticum aestivum L.) under Al stress. Hydroponic experiments were performed by wheat ET8 (Al-tolerant). The efflux of malic acid was investigated under different treatments. Results showed that Al treatments increased the accumulation of endogenous IAA, but decreased the activity of IAA oxidase in a dose-dependent manner. A good correlation between all the data of malic acid efflux rate and endogenous IAA content was obtained (R2= 0.9859**). IAA treatment alone had no effect on the efflux of malic acid. But compared to Al (50 μM) treatment, the efflux of malic acid increased significantly under the co-treatment of IAA (50 μM) and Al (50 μM). In split-root experiments, the root with half of it being treated with Al (CK/Al), the other part (CK) showed significantly higher malic acid efflux rate and endogenous IAA content in root apexes, compared with the root without such treatment (CK/CK). The Al-induced malic acid efflux decreased under the treatments of IAA transport inhibitor N-l-napthyl-phtalamic acid (NPA) (or 2,3,5-triiodobenzoic acid, TIBA). These above results suggested the possible involvement of IAA in the stimulation of malic acid efflux under Al stress. In addition, anion channel inhibitor treatment experiment showed that IAA (50 μM) relieved the inhibiting effect of 5 μM anthracene-9-carboxylic acid (A9C) (or niflumic acid, NIF) on malic acid efflux induced by Al (50 μM), compared to the cotreatment of Al (50 μM) and 5 μM anion channel inhibitor A9C (or NIF) it is thus speculated that the anion channel might have been activated when IAA was involved in malic acid efflux. This study showed that IAA was involved in aluminuminduced efflux of malic acid from wheat.