Urease deficiency alters nitrogen metabolism and gene expression in urease-null soybean without affecting growth or productivity under nitrate supply

摘要: Urea is a product of arginine catabolism in plants and its Nitrogen recycled into the plant metabolism as ammonium after hydrolysis by urease. The eu3-a soybean mutant null for Ni insertion protein (UreG) necessary urease activity. No UreG nor any activity enzymes detectable these mutants. In order to understand mechanisms nitrogen cycling possible physiological benefits N metabolism, (urease-null) control near-isogenic Eu3 were studied. They grown two different developmental stages (vegetative-V5 reproductive-R5) with 15 mM nitrate sole source nitrogen. Growth biochemical parameters (such amino acid, nitrate, polyamine pools) evaluated leaves. Gene transcript levels determined some related Arg catabolism, together those DUR3 active urea transporter Ni-insertion accessory protein, whose was confirmed be absent eu3-a. absence did not affect growth or yield although there substantial progressive accumulation Metabolic changes occurred mainly pool acids expression genes pathway degradation. There are indications that may diverted form polyamines, but limited extent. Thus, considering both stages, degradation Orn remains main path recycling from Arg, despite consequently immobilization N.