The accumulation and transport of abscisic acid insoybean (Glycine max L.) under aluminum stress

Abstract

Abscisic acid (ABA) plays an important role in mediating some biotic and abiotic stresses. In the present study, to better understand the relationship of ABA production and Aluminum (Al)-resistance in plants, Al-resistance genotype (Jiyu70) of soybean was adopted to investigate the accumulation and transport of ABA in plants exposed to Al. Results showed that exogenous application of ABA and ABA synthesis inhibitor-fluridone respectively increased and reduced endogenous ABA content in root apices of soybean, and results in the corresponding reduction and aggravation of Al toxicity. Increasing of either Al concentration (0-50 μM) or treatment duration (0-12 h, 30 μM Al) cause a higher inhibition of root elongation and ABA accumulation in root apices of soybean. Al-induced enhancement of endogenous ABA production not only was in roots but also in leaves, whereas La 3+ (behaves similarly as Al 3+ at the level of cell surface) only increased ABA accumulation in roots. In split-root experiments, Al treatment in two parts of roots (Part A, + Al; Part B, + Al) both decreased root elongation and increased ABA accumulation in root apices of soybean. Whereas when only part A of roots was exposed to Al (Part A, + Al; Part B, -Al), endogenous ABA content in root apices increased in part A but inversely in part B, but root elongation inhibition only was found in part A. Using [ 3 H]-ABA radioisotope technique, it was found that [ 3 H]-ABA can transport at the rate of more than 3.2 cm·min −1 in the whole plants, and this can be accelerated by Al supply. In addition, [ 3 H]-ABA tended to distribute in the root part under Al stress. Together, these results suggest that ABA may play an important role in regulating Al resistance of soybean as an Al-stress signal.

Characterization of the Complex Regulation of AtALMT1 Expression in Response to Phytohormones and Other Inducers

“…1A) could protect the roots from Al rhizotoxicity, which, if unchecked, could further exacerbate drought sensitivity by inhibiting root development. In addition, ABA accumulation in response to Al occurs in some crop plants such as barley (Hordeum vulgare) and soybean (Glycine max; Kasai et al, 1993;Hou et al, 2010). Together, these findings suggest that responses involving IAA and ABA play a role in Al tolerance in Arabidopsis in the natural soil environment.…”

Interaction of aluminium and drought stress on root growth and crop yield on acid soils

“…Several hydroponic studies have shown that Al induces ABA production in the root tips of soybean (Hou et al 2010;Shen et al 2004) and barley (Kasai et al 1993), which was supposed to regulate Al resistance mechanisms (Hou et al 2010;Shen et al 2004 (2010, 2011c, 2012) root tips and had no effect on the expression of genes involved in ABA biosynthesis . In spite of this, under combined Al and drought-stress conditions Al suppressed the drought-stimulated ABA production as well as the expression of the NCED gene in the root tips.…”

Interactions between nitric oxide and plant hormones in aluminum tolerance

“…The change in CK level precedes the Al-induced inhibition of root elongation, which may contribute to inhibition by promoting ethylene production or auxin accumulation. 9 Al-induced ethylene production is associated with inhibition of root elongation in Lotus japonicas, 10 but it is not a key factor in the Al-induced inhibition of root elongation that lags an increase of CK. Asymmetrical exposure of CK at the root tip promotes cell elongation, and ethylene signaling work downstream of CK of transducer the signal further.…”

“…8 Al rapidly stimulated an increase of CK to inhibit root elongation in Phaseolus vulgaris. The change in CK level precedes the Al-induced inhibition of root elongation, which may contribute to inhibition by promoting ethylene production or auxin accumulation.…”