Role of organic acids in the metabolism and recycling of N in the roots of soybean

• Grant number: 13/03325-8
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): July 01, 2013
• Effective date (End): February 28, 2017
• Field of knowledge: Biological Sciences - Botany
• Principal Investigator: Ladaslav Sodek
• Grantee: Simone Cespedes Vitor
• Home Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The transport of organic compounds by the vascular system of plants is becoming increasingly important not only as a nutrient supply for plant organs but in the regulation of physiological processes in different plant parts. In some cases such transport involves the recycling of compounds between root and shoot, a process under strong influence of the demand of different plant organs for nutrients. The phenomenon of recycling has been studied most extensively in the case of N. However, recent work suggests that organic acids (carboxylates) may also play an important role in the process of N recycling, not only because of their close relationship with N metabolism but through active participation together with amino acids as transport compounds in the vascular system. Our hypothesis is that the recycling of organic acids in soybean is closely related to the metabolism of the principal amino acids, aspartate and glutamate, supplied by the phloem to the roots. In a root system deficient in N, the supply of these amino acids via phloem will result in organic acid formation as products of the transamination reactions necessary for the formation of other amino acids. In a root system with active N assimilation, these phloem amino acids will serve as precursors of the products of assimilation, glutamine and asparagine, and not lead to organic acid formation. Our objective is to establish and characterize this role as a general phenomenon in diverse situations based on one known case specific to waterlogged plants under hypoxic stress, where clear evidence is available for the participation of organic acids in this context. To meet this objective, our approach will be to determine the content of key organic acids in the root and vascular systems in relation to the state of N sufficiency in the root and to verify the metabolic interaction between organic acids and amino acids in the leaf in relation to recycling of C and N in the root. Since N sufficiency or deficiency can easily be obtained by varying the growth conditions, such growth conditions will be used to investigate their influence on the metabolism and transport of organic acids and relate these to known changes in amino acid recycling and metabolism in the root system. With this approach we expect to obtain new data that may reveal a new concept in this field, principally regarding the comprehension of N use by the plant and the interaction of C and N. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

VITOR, SIMONE CESPEDES; SODEK, LADASLAV. Products of anaerobic metabolism in waterlogged roots of soybean are exported in the xylem. Plant Science, v. 284, p. 82-90, JUL 2019. Web of Science Citations: 0.

VITOR, SIMONE C.; DO AMARANTE, LUCIANO; SODEK, LADASLAV. Are phloem-derived amino acids the origin of the elevated malate concentration in the xylem sap following mineral N starvation in soybean?. PLANTA, v. 248, n. 2, p. 437-449, AUG 2018. Web of Science Citations: 3.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

VITOR, Simone Cespedes. Role of organic acids in the metabolism and recycling of N in soybean under root stress : N deficiency and hypoxia. 2017. Doctoral Thesis - Universidade Estadual de Campinas, Instituto de Biologia.