Nicotianamine: A Key Player in Metal Homeostasis and Hyperaccumulation in Plants

Abstract

Nicotianamine (NA) is a low-molecular-weight N-containing metal-binding ligand, whose accumulation in plant organs changes under metal deficiency or excess. Although NA biosynthesis can be induced in vivo by various metals, this non-proteinogenic amino acid is mainly involved in the detoxification and transport of iron, zinc, nickel, copper and manganese. This review summarizes the current knowledge on NA biosynthesis and its regulation, considers the mechanisms of NA secretion by plant roots, as well as the mechanisms of intracellular transport of NA and its complexes with metals, and its role in radial and long-distance metal transport. Its role in metal tolerance is also discussed. The NA contents in excluders, storing metals primarily in roots, and in hyperaccumulators, accumulating metals mainly in shoots, are compared. The available data suggest that NA plays an important role in maintaining metal homeostasis and hyperaccumulation mechanisms. The study of metal-binding compounds is of interdisciplinary significance, not only regarding their effects on metal toxicity in plants, but also in connection with the development of biofortification approaches to increase the metal contents, primarily of iron and zinc, in agricultural plants, since the deficiency of these elements in food crops seriously affects human health.

Physiological and Transcriptomic Analyses Reveal Commonalities and Specificities in Wheat in Response to Aluminum and Manganese

“…Nicotianamine (NA) is a low-molecular-weight metal-bound ligand that maintains the homeostasis of Fe, Zn, and Mn. It protects cells from metal-induced damage, such as oxidative stress [46]. L-methionine is the precursor for NA biosynthesis, which binds with ATP to synthesize S-adenosylmethionine (SAM).…”

“…NA is finally converted into 2 ′ -deoxymugineic acids (DMA) and other mugineic acids (MAs) under the catalysis of nicotianamine aminotransferase (NAAT) [47]. The overexpression of MxNAS2 and MxNAS3 genes from M. xiaojinensis increases the concentration of NA-Mn in the flowers and leaves of tobacco and Arabidopsis, respectively [46]. Yellow strip-like protein (YSL) is involved in the uptake, transport, and relocation of metal complexes such as Mn-NA, Mn-HMA, and Mn-DMA to maintain Mn ion balance in plants [6,48].…”

Coordination chemistry suggests that independently observed benefits of metformin and Zn2+ against COVID-19 are not independent

“…Nature was a student of coordination chemistry and ligand exchange. Nicotianamine, staphylopine and yersinopine are hexadentate counterparts of EDTA in plants and bacteria (Seregin & Kozhevnikova 2023 ); others might be discovered. For practical purposes, a metallophore might be distinguished from other metal-interactive substances by the nature of the interacting forces, e.g.…”

Physiological and Transcriptomic Analyses Reveal Commonalities and Specificities in Wheat in Response to Aluminum and Manganese

“…Nicotianamine (NA) is a low-molecular-weight metal-bound ligand that maintains the homeostasis of Fe, Zn, and Mn. It protects cells from metal-induced damage, such as oxidative stress [49]. L-methionine is the precursor for NA biosynthesis, which binds with ATP to synthesize Sadenosylmethionine (SAM).…”