The Role of Ligand Exchange in the Uptake of Iron from Microbial Siderophores by Gramineous Plants

Screening of plant growth promoting traits ofBacillus thuringiensis

“…In the case of B. thuringiensis this character could be relevant for biocontrol of phytopathogenic fungi due to competition effects for iron, but also for providing the plant with iron. Indeed, a number of plants possess heterologous iron uptake mechanism for acquisition of iron through iron-bacterial siderophore complex (Yehuda et al, 1996;Sharma et al, 2003). The role of soil microbial activity in iron acquisition and plant growth has been reported by Masalha et al (2000) who found that under non-sterile soil system, plants show no iron-deficiency symptoms and have fairly high iron level in roots, in contrast to plants grown in sterile system.…”

Mechanisms of plant growth stimulation by humic substances: The role of organo-iron complexes

“…Ryegrass is a very common plant on golf courses and is therefore of importance to the industry. It is a monocotyledonous gramineae and like other members of its family, takes up Fe from the soil or from nutrient solutions via a ligand exchange mechanism between organo-Fe complexes and/or mineral Fe compounds and phytosiderophores (Romheld and Marschner 1986;Yehuda et al 1996). As for the dicotyledonous plants, we hypothesized that the formation of organo-Fe complexes in the NS and the resulting maintenance of the Fe in solution will greatly improve the effectiveness of the Fe uptake mechanism via the phytosiderophores.…”

“…These complexing agents include dissolved organic matter (DaM), organic acids, microbial siderophores and phytosiderophores, as well as fractions of humified OM (Stevenson 1991). The involvement of such compounds in the Fe nutrition of plants has been clearly demonstrated (Barak and Chen 1982;Marschner et al 1986b;Shenker et al 1992;Wang et al 1993;Yehuda et al 1996). To cope with Fe shortage during growth, the plant kingdom has developed two main strategies (Rbmheld and Marschner 1994), as follows: 1) Fe-deficient dicotyledonous plants and nongrass monocots increase their capacity of acidifying the rhizosphere, develop an enhanced level of a reductase enzyme on the root surface and release reductants to the soil solution.…”

Siderophore Production and Induction of Iron-regulated Proteins by a Microorganism from Rhizosphere of Barley

“…[1][2][3] Some plants produce phytosiderophores for iron acquisition from soil under irondeˆcient conditions. 4,5) Mugineic acids have been isolated from the roots of barley, a gramineous plant, and are important in acquiring insoluble iron from soil for optimal growth of the plant. 6) In addition, there is another possibility, that plants use microbial siderophores for iron acquisition.…”