Abstract
SORBITOL DEHYDROGENASE (SDH, EC 1.1.1.14) catalyses the interconversion of polyols and ketoses (e.g. sorbitol ↔ fructose). Using two independent Arabidopsis thaliana (L.) Heynh. sdh knockout mutants, we show that SDH (At5g51970) plays a primary role in sorbitol metabolism as well as an unexpected role in ribitol metabolism. Sorbitol content increased in both wild-type (WT) and mutant plant leaves during drought stress, but mutants showed a dramatically different phenotype, dying even if rewatered. The lack of functional SDH in mutant plants was accompanied by accumulation of foliar sorbitol and at least 10-fold more ribitol, neither of which decreased in mutant plants after rewatering. In addition, mutant plants were uniquely sensitive to ribitol in a concentration-dependent manner, which either prevented them from completing seed germination or inhibited seedling development, effects not observed with other polyols or with ribitol-treated WT plants. Ribitol catabolism may occur solely through SDH in A. thaliana, though at only 30% the rate of that for sorbitol. The results indicate a role for SDH in metabolism of sorbitol to fructose and in ribitol conversion to ribulose in A. thaliana during recovery from drought stress.
Original language | English |
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Pages (from-to) | 462-470 |
Number of pages | 9 |
Journal | Functional Plant Biology |
Volume | 39 |
Issue number | 6 |
DOIs | |
State | Published - 2012 |
Keywords
- carbohydrate metabolism
- polyol metabolism
- seed germination
ASJC Scopus subject areas
- Agronomy and Crop Science
- Plant Science