Glycolysis and the tricarboxylic acid cycle are linked by alanine aminotransferase during hypoxia induced by waterlogging of Lotus japonicus.
The role of nitrogen metabolism in the survival of prolonged periods of waterlogging was investigated in highly flood-tolerant, nodulated Lotus japonicus plants. Alanine production revealed to be a critical hypoxic pathway. Alanine is the only amino acid whose biosynthesis is not inhibited by nitrogen deficiency resulting from RNA interference silencing of nodular leghemoglobin. The metabolic changes that were induced following waterlogging can be best explained by the activation of alanine metabolism in combination with the modular operation of a split tricarboxylic acid pathway. The sum result of this metabolic scenario is the accumulation of alanine and succinate and the production of extra ATP under hypoxia. The importance of alanine metabolism is discussed with respect to its ability to regulate the level of pyruvate, and this and all other changes are discussed in the context of current models concerning the regulation of plant metabolism.
Rocha
Marcio
M
Max Planck Institute of Molecular Plant Physiology, Energy and Central Metabolism Research Groups, D-14476 Potsdam-Golm, Germany.
Licausi
Francesco
F
Araújo
Wagner L
WL
Nunes-Nesi
Adriano
A
Sodek
Ladaslav
L
Fernie
Alisdair R
AR
van Dongen
Joost T
JT
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000409:Alanine / Q000096:biosynthesis; D000410:Alanine Transaminase / Q000235:genetics / Q000378:metabolism*; D002952:Citric Acid Cycle; D005285:Fermentation; D018506:Gene Expression Regulation, Plant; D006019:Glycolysis; D000860:Hypoxia; D007874:Leghemoglobin / Q000235:genetics; D000070116:Lotus / Q000235:genetics / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation / Q000235:genetics; D019289:Pyruvic Acid / Q000378:metabolism; D034622:RNA Interference; D019802:Succinic Acid / Q000378:metabolism; D014867:Water
D007874:Leghemoglobin; D014867:Water; D019289:Pyruvic Acid; D000255:Adenosine Triphosphate; D019802:Succinic Acid; D000410:Alanine Transaminase; D009584:Nitrogen; D000409:Alanine