Up-regulation of glutathione metabolism and changes in redox status involved in adaptation of reed (Phragmites communis) ecotypes to drought-prone and saline habitats.
The glutathione (GSH) metabolic characteristics and redox balance in three ecotypes of reed (Phragmites communis), swamp reed (SR), dune reed (DR), and heavy salt meadow reed (HSMR), from different habitats in desert regions of northwest China were investigated. The DR possessed the highest rate of GSH biosynthesis and metabolism with the lowest levels of total and reduced GSH and its biosynthetic precursors, gamma-glutamylcysteine (gamma-EC) and cysteine (Cys), of the three reed ecotypes. This suggests that a higher rate of GSH biosynthesis and metabolism, but not GSH accumulation, might be involved in the adaptation of this terrestrial reed ecotype to its dry habitat. The HSMR shared this profile although it exhibited the highest reduced thiol levels of the three ecotypes. Two key enzymes in the Calvin-cycle possessing exposed sulfhydryl groups, NADP(+)-dependent glyceraldehydes-3-phosphate dehydrogenase (G3PD) and fructose-1,6-bisphosphatase (FBPase), and other two key enzymes in the pentose-phosphate pathway (PPP), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6-PGD), had very similar activities in the three reed ecotypes. Compared to the SR, the DR and HSMR had higher ratios of NADPH/NADP+ and NADH/NAD+, indicating that a more reduced redox status in the plant cells might be involved in the survival and adaptation of the two terrestrial reed ecotypes to long-term drought and salinity, respectively. These results suggest that changes of GSH metabolism and redox balance were important components of the adaptation of reed, a hydrophilic plant, to more extreme dune and saline habitats. The coordinated up-regulations of the rate of GSH biosynthesis and metabolism and reduction state of redox status of plant cells, conferred on the plant high resistance or tolerance to long-term drought and salinity.
Chen
Kun-Ming
KM
College of Life Sciences, Lanzhou University, Lanzhou, P.R. China 730000.
Gong
Hai-Jun
HJ
Chen
Guo-Cang
GC
Wang
Suo-Min
SM
Zhang
Cheng-Lie
CL
D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology*; D004190:Disasters; D004463:Ecology; D004777:Environment; D006597:Fructose-Bisphosphatase / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005978:Glutathione / Q000096:biosynthesis / Q000378:metabolism*; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000378:metabolism; D010084:Oxidation-Reduction; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism; D006109:Poaceae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D014867:Water / Q000378:metabolism
D014867:Water; D012965:Sodium Chloride; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D006597:Fructose-Bisphosphatase; D005978:Glutathione