Mustroph, A; Hess, N; Sasidharan, R: Hypoxic energy metabolism and PPi as an alternative energy currency, Plant Cell Monographs, Low-Oxygen Stress in Plants, Springer-Verlag Wien, 21, 165-184 (2014), doi:10.1007/978-3-7091-1254-0_9 | |
Abstract: During periods of oxygen-deficiency stress, mitochondrial respiration in plants is strongly inhibited and ATP production decreases. One potential strategy to cope with this energy crisis is the induction of enzymes that use pyrophosphate (PPi) as the energy source as an alternative to ATP-using enzymes. Four enzymatic pathways in plant primary metabolism are discussed here in the context of available gene expression and proteomic studies as well as mutant analyses. One PPi-dependent pathway, sucrose cleavage by sucrose synthase and UDP-glucose pyrophosphorylase, is clearly important for plant hypoxic metabolism, while the impact of the other three enzymes, pyrophosphate: fructose-6-phosphate phosphotransferase, pyruvate-orthophosphate dikinase, and vacuolar proton-transporting pyrophosphorylase in plants remains unclear and needs to be studied further. The latter three enzymes could be potentially involved in the flooding tolerance of species such as Rorippa sylvestris or Oryza sativa as indicated by gene expression and activity data. |