Phloem transport of amino acids is differentially altered by phosphorus deficiency according to the nitrogen availability in young barley plants

Autor: Maria Victoria Criado, Carla Caputo, Irma N. Roberts, Cintia G. Veliz
Jazyk: angličtina
Rok vydání: 2017
Předmět:
DOI: 10.1007/s10725-017-0247-6
Popis: The phloem transport of amino acids is a key step in the efficient use of nitrogen (N). Despite the importance of this issue, little information is known about the regulation of phloem transport of amino acids in plants with low phosphorus (P) supply and even less in relation to N availability. To this end, we studied not only the assimilate partitioning in young barley plants grown with low N or/and P supply, but also we analyzed the implications of the different isoforms of glutamine synthetase, cytokinin oxidase/dehydrogenase 2 and several senescence-related proteases. Our results demonstrated that low P supply causes an accumulation of different nitrogenous compounds in expanded leaves depending on N availability and an inhibition of the phloem exudation rate of amino acids only in high-N plants, indicating an interaction between N and P in the establishment of N-partitioning. The accumulation of nitrogenous compounds in leaves of low-P plants without the accompaniment in amino acid export to the phloem was not related to an increase in nitrate assimilation pathway neither with the modulation of glutamine synthetase 1_1 expression, as it had been observed for N availability. But, these results could be explained as a consequence of a delay in the transition from sink to source of leaves, thus keeping the older leaves as sink organs, as indicated by the increase in cytokinin oxidase/dehydrogenase 2 expression and the repression of several senescence-related proteases in low-P plants with good availability of N. Fil: Criado, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Veliz, Cintia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Roberts, Irma. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Caputo Suarez, Carla Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina
Databáze: OpenAIRE