Release of phytosiderophores from roots of wheat and triticale under nickel‐deficient conditions

Abstract

Despite numerous studies on phytosiderophores (PS) there is still an open question whether nickel (Ni) deficiency induces release of PS from graminaceous plant roots. Seedlings of two wheat cultivars (Triticum aestivum L. cvs. Rushan and Kavir) and a triticale cultivar (X. triticosecale) were grown in Ni‐free nutrient solution (Ni‐deficient, Ni–) and with 10 µM NiSO4 (Ni‐sufficient, Ni+, control). Root exudates were collected weekly for 4 weeks and the amount of PS in the root exudates was measured. The response to Ni deficiency on the release of PS differed between species. Roots of Rushan and triticale exuded higher PS in response to Ni‐deficient conditions. Nickel deficiency significantly enhanced shoot Fe and Zn concentrations in wheat, while it decreased shoot Fe and Zn concentrations in triticale. In Kavir, PS exudation was decreased by Ni deficiency at weeks 3 and 4 and the reduced release of PS from roots of Kavir was accompanied by lower concentrations of Fe and Zn in plant roots but higher Fe and Zn concentrations in shoot tissue. The PS release by Kavir was triggered by a Ni‐induced Zn deficiency particularly in the shoots. According to the results, it is suggested that in the studies concerning the phytosiderophore release under Ni deficiency, special attention should be given to different responses among and within cereals and to the plant Zn or Fe nutritional status.

Possible Roles of Rhizospheric and Endophytic Microbes to Provide a Safe and Affordable Means of Crop Biofortification

“…Aluminum-activated malate transporters (ALMTs) and the multidrug and toxic compound extrusion (MATE) family of transporters responsible for exporting malate and citrate are among the few well-understood examples of transporters involved in organic acid exudation [158]. These root exudates also improve the cation exchange capacity in the soil by providing ion exchange sites for Zn and other mineral elements [167]. Root exudates also include nucleotides (adenosine, guanosine, cytidine, thymine) and oligopeptides which are also actively imported by secondary transporters, but the mechanisms of their exudation remain unclear [168,169].…”