Alteration of cell-wall porosity is involved in osmotic stress-induced enhancement of aluminium resistance in common bean (Phaseolus vulgaris L.)
نویسندگان
چکیده
Aluminium (Al) toxicity and drought are the two major abiotic stress factors limiting common bean production in the tropics. Using hydroponics, the short-term effects of combined Al toxicity and drought stress on root growth and Al uptake into the root apex were investigated. In the presence of Al stress, PEG 6000 (polyethylene glycol)-induced osmotic (drought) stress led to the amelioration of Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1. PEG 6000 (>> PEG 1000) treatment greatly decreased Al accumulation in the 1 cm root apices even when the roots were physically separated from the PEG solution using dialysis membrane tubes. Upon removal of PEG from the treatment solution, the root tips recovered from osmotic stress and the Al accumulation capacity was quickly restored. The PEG-induced reduction of Al accumulation was not due to a lower phytotoxic Al concentration in the treatment solution, reduced negativity of the root apoplast, or to enhanced citrate exudation. Also cell-wall (CW) material isolated from PEG-treated roots showed a low Al-binding capacity which, however, was restored after destroying the physical structure of the CW. The comparison of the Al(3+), La(3+), Sr(2+), and Rb(+) binding capacity of the intact root tips and the isolated CW revealed the specificity of the PEG 6000 effect for Al. This could be due to the higher hydrated ionic radius of Al(3+) compared with other cations (Al(3+) >> La(3+) > Sr(2+) > Rb(+)). In conclusion, the results provide circumstantial evidence that the osmotic stress-inhibited Al accumulation in root apices and thus reduced Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1 is related to the alteration of CW porosity resulting from PEG 6000-induced dehydration of the root apoplast.
منابع مشابه
Proteomic and phosphoproteomic analysis of polyethylene glycol-induced osmotic stress in root tips of common bean (Phaseolus vulgaris L.)
Previous studies have shown that polyethylene glycol (PEG)-induced osmotic stress (OS) reduces cell-wall (CW) porosity and limits aluminium (Al) uptake by root tips of common bean (Phaseolus vulgaris L.). A subsequent transcriptomic study suggested that genes related to CW processes are involved in adjustment to OS. In this study, a proteomic and phosphoproteomic approach was applied to identif...
متن کاملMorpho-Physiological Characterization Related to Drought Tolerance of Common Bean (Phaseolus Vulgaris L.) Genotypes
Drought is one of the limiting factor in common bean, development of common bean varieties that adapted to drought situations is the main focus for improving food crops. In this study, 25 genotypes of common beans (Phaseolus vulgaris L.) were grown under drought stress and non-stress conditions. The field work was conducted at Melkassa Agricultural Research Center during the off-season that lai...
متن کاملMorpho-Physiological Characterization Related to Drought Tolerance of Common Bean (Phaseolus Vulgaris L.) Genotypes
Drought is one of the limiting factor in common bean, development of common bean varieties that adapted to drought situations is the main focus for improving food crops. In this study, 25 genotypes of common beans (Phaseolus vulgaris L.) were grown under drought stress and non-stress conditions. The field work was conducted at Melkassa Agricultural Research Center during the off-season that lai...
متن کاملPhysiological and molecular analysis of the interaction between aluminium toxicity and drought stress in common bean (Phaseolus vulgaris)
Aluminium (Al) toxicity and drought are two major factors limiting common bean (Phaseolus vulgaris) production in the tropics. Short-term effects of Al toxicity and drought stress on root growth in acid, Al-toxic soil were studied, with special emphasis on Al-drought interaction in the root apex. Root elongation was inhibited by both Al and drought. Combined stresses resulted in a more severe i...
متن کامل