Nickel Deficiency Disrupts Metabolism of Ureides, Amino Acids, and Organic Acids of Young Pecan Foliage

Abstract

The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan.Relatively little is known about the role of nickel (Ni) in plant nutrition, physiology, and metabolism, especially in woody perennial species, such as pecan (Carya illinoinensis [Wangenh.] K. Koch). Ni was suspected of possessing a metabolic role in plants when discovered as a constituent of plant ash in the early 20th century. Evidence for a key metabolic role was strengthened with observation of field-level growth responses to foliar Ni applications to crops as diverse as wheat (Triticum aestivum), potatoes (Solanum tuberosum), and broad beans (Vicia faba; Roach and Barclay, 1946;Dobrolyubskii and Slavvo, 1957;Welch, 1981).

GC-TOF-MS based metabolomics and ICP-MS based metallomics of cucumber (Cucumis sativus) fruits reveal alteration of metabolites profile and biological pathway disruption induced by nano copper

“…The down-regulated citric acid is likely evidence that nCu influences the availability of acetylCoA. 63 Interestingly, most of the metabolites related to carbohydrate metabolism are reported to be a response to iron deficiency in the leaves and xylem sap of several plant species, including peach, tomato, and sugar beet. 64 It has been demonstrated that the response of leaves to iron deficiency is up-regulation of carbohydrates and TCA cycle metabolites and N-related metabolites.…”

Fortification of micronutrients for efficient agronomic production: a review

“…However, the systemic, nonpoint source effects observed in plants upon application of micronutrients suggest that, in addition to pathogen toxicity, they might also directly be involved in physiological processes that confer plant resistance to diseases. Such processes include stimulating the production of antioxidants and other pathogen inhibitory compounds, influencing lignin and suberin biosynthesis to toughen cell walls and reduce pathogen infiltration, and modulating N metabolism in the plant (Huber and Wilhelm 1988;Römheld and Marschner 1991;Boyd et al 1994;Bai et al 2006;Evans et al 2007;Stangoulis and Graham 2007;Taran et al 2014;Servin et al 2015a). Notably, B's involvement in cell wall regulation is related to the modulation of Ca balance in the cell wall, helping in the formation of calcium pectate that confer rigidity to the plant (Stangoulis and Graham 2007), which otherwise would be more easily weakened by disease or drought stress.…”

Metal uptake, antioxidant status and membrane potential in maize roots exposed to cadmium and nickel

“…No doubt, the occurrence of HMs can be both beneficial and harmful for plants (Meuwly & Rauser 1992;Rauser & Meuwly 1995;Schützendübel & Polle 2002;Seregin & Kozhevnikova 2006). Unlike Ni, that is a component of urease and at low concentrations stimulates growth of some plants (Bai et al 2006), Cd is not involved in any known physiological function within a plant body and has been reported to cause deleterious effects on plants (Tran & Popova 2013).…”