Response of carbon and nitrogen-rich metabolites to nitrogen deficiency in PSARK::IPT tobacco plants.
Wild type (WT) and transgenic tobacco plants expressing isopentenyltransferase (IPT), a gene coding the rate-limiting step in cytokinin (CKs) synthesis, were grown under limited nitrogen (N) conditions. Here, we analyse the possible effect of N deficiency on C-rich compounds such as phenolic compounds, as well as on N-rich compounds such as polyamines (PAs) and proline (Pro), examining the pathways involved in their synthesis and degradation. N deficiency was found to stimulate phenolic metabolism and increase these compounds both in P(SARK):IPT as well as in WT tobacco plants. This suggests that nitrate (NO(3)(-)) tissue concentration may act as a signal triggering phenolic compound accumulation in N deficiency plants. In addition, we found the maintenance of PAs in the WT plants would be correlated with the higher stress response to N deficiency. On the contrary, the reduction of free PAs and Pro found in the P(SARK)::IPT plants subjected to N deficiency would indicate the operation of an N-recycling mechanism that could stimulate a more efficient N utilization in P(SARK)::IPT plants.
Department of Plant Physiology, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain. mmrubio@ugr.es
María del Mar
Mdel M
Rubio-Wilhelmi
Eva
E
Sanchez-Rodriguez
Rocio
R
Leyva
Begoña
B
Blasco
Luis
L
Romero
Eduardo
E
Blumwald
Juan Manuel
JM
Ruiz
D019883:Alkyl and Aryl Transferases / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000172:deficiency / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*
D009566:Nitrates; D002244:Carbon; D019883:Alkyl and Aryl Transferases; C024274:adenylate isopentenyltransferase; D009584:Nitrogen