Plant Physiol, July 2002, Vol. 129, pp. 1352-1358
Arabidopsis Mutants Deficient in Diacylglycerol Acyltransferase
Display Increased Sensitivity to Abscisic Acid, Sugars, and Osmotic
Stress during Germination and Seedling Development1
Chaofu
Lu2 and
Matthew J.
Hills*
John Innes Centre, Colney Lane, Norwich, NR4 7UH, United
Kingdom
Arabidopsis seeds store triacylglycerol (TAG) as the major
carbon reserve, which is used to support postgerminative seedling growth. Diacylglycerol acyltransferase (DGAT) catalyzes the final step
in TAG synthesis, and two isoforms of DGAT have previously been
identified in Arabidopsis. It has been shown that DGAT1 plays an
important role in seed development because Arabidopsis with mutations
at the TAG1 locus accumulate less seed oil. There is also evidence showing that DGAT1 is active after seed germination. The
aim of this study is to investigate the effect of mutations of DGAT1 on
postembryonic development in Arabidopsis. We carried out detailed
analyses of two tag1 mutants in different ecotypic backgrounds of Arabidopsis. Results show that during germination and
seedling growth, seed storage TAG degradation was not affected in the
tag1 mutants. However, sugar content of the mutant
seedlings is altered, and activities of the hexokinases are
significantly increased in the tag1 mutant seedlings.
The tag1 mutants are also more sensitive to abscisic
acid, glucose, and osmotic strength of the medium in germination and
seedling growth.
1
This work was supported by The Biotechnology and
Biological Sciences Research Council through the Competitive Strategic
Grant to the John Innes Centre and through a research grant under the "Genome Analysis of Agriculturally Important Traits" initiative.
2
Present address: Institute of Biological Chemistry,
Washington State University, Pullman, WA 99164-6340.
*
Corresponding author; e-mail matthew.hills{at}bbsrc.ac.uk; fax
44-1603-450014.
© 2002 American Society of Plant Physiologists
