Amino Acid Metabolism and Transport in Soybean Plants

Abstract

The ammonium produced by nitrogen fixation in the bacteroid is rapidly excreted to cytosol of infected cell of soybean nodules and then assimilated into glutamine and glutamic acid, by glutamine synthetase/glutamate synthase pathway. Most of the nitrogen is further assimilated into ureides, allantoin, and allantoic acid, via purine synthesis, and they are transported through xylem to the shoots. Nitrate absorbed in the roots is reduced by nitrate reductase and nitrite reductase to ammonia either in the roots or leaves. The ammonia is also assimilated by glutamine synthetase/glutamate synthase pathway, and mainly transported by asparagine, and not ureides. The nitrogen transported into leaves is readily utilized for protein synthesis, and then, some of them are decomposed and retransported to roots, apical shoots, and pods via phloem mainly in the form of asparagine.

Fe2O3 nanoparticles induced biochemical responses and expression of genes involved in rosmarinic acid biosynthesis pathway in Moldavian balm under salinity stress

“…Osmotic regulation through the accumulation of amino acids such as Gly, Pro, Ala and Val (Ahmed et al ), detoxification of ROS and intracellular pH adjustment (Hayat et al ) are parts of amino acids roles in plants in stress states. Some amino acids are used in the synthesis of proteins, some serve as sources of nitrogen (Ohyama et al ), and some other are used as biosynthetic precursors for secondary compounds (Rampino et al ). The shikimate pathway provides the carbon skeleton for aromatic amino acids, including L‐Trp, L‐Phe and L‐Tyr.…”

Hidden Nickel Deficiency? Nickel Fertilization via Soil Improves Nitrogen Metabolism and Grain Yield in Soybean Genotypes

“…To be able to transport N-urea to N-sink tissues, soybean plants produce ammonia, as result of urea hydrolysis by urease activity (Wang et al, 2008 ; Witte, 2011 ; Polacco et al, 2013 ; Winter et al, 2015 ). According to Mokhele et al ( 2012 ) and Ohyama et al ( 2017 ), when degraded, ammonia produces different amino acids, so that a higher free amino acid pool affect positively several plant-growth process, especially secondary compounds synthesis. Although little is known about Ni influences ammonia metabolism in plants, Bai et al ( 2006 , 2007 ) observed that pecan plants under low Ni supply showed an inhibition in the shikimate pathway, disrupting the conversion of free amino acids to other products and, thus, blocking some N pathways.…”

Biochemical Changes During Flowering of Spathodea campanulata P. Beauv

“…In S. campanulata the abundant free amino acid concentration in the calyx of middle stage is unique and different from rest of the floral development studies, which may be due to the endophytic microorganism present in the glands contributing to amino acid content by nitrogen fixation. 31,32 The free amino acid concentration in corolla exhibited high quantity than calyx, indicating the demand for the same in the actively developing corolla, which is about to open, similar to Hemrocallis and Consolida. [33][34][35][36] The decrease in free amino acid in large stage could be due to senescence and transition of amino acid pool to the other developing floral organs.…”