Quantitative proteomic analysis of Arabidopsis thaliana with different levels of phospholipid:diacylglycerol acyltransferase1 expression.

Background: Phospholipid:diacylglycerol acyltransferase1 (PDAT1) enzyme is known to play an important role in lipid metabolism. Initially, it was suggested that the construction of PDAT1 overexpressors may result in plant varieties with increased oil content. Contrary to those expectations, Arabidopsis thaliana lines overexpressing AtPDAT1 did not exhibit an increased accumulation of the triacylglycerol pool. However, the overexpressing lines exhibited accelerated growth rate, increased seed yield, and when subjected to cold treatments, they had greater thermotolerance, whereas knock-out line were more susceptible than the wild-type.

Result: In this work, we have performed a comparative proteomic analysis among wild-type, AtPDAT1-overexpressing and knock-out lines of Arabidopsis thaliana. For overexpressor lines we have observed significant changes in protein profiles related to processes that may partially explain increased plant vitality. Among others, we noticed elevated levels of subsequent groups of proteins: plastoglobule structural components and associated enzymes, proteins involved in photoprotection and in autophagy. The overexpressor lines were also characterized by upregulated level of proteins involved in abiotic stress responses, whereas the level of the proteins involved in biotic stress responses was downregulated. The opposite results were detected for the knock-out line.

Conclusion: These results reveal a wide range of proteomic changes that reflect cellular alterations - some of which are supported by previous physiological and biochemical studies - induced by the genetic manipulation of a single gene encoding an enzyme directly involved in lipid metabolism. The results suggest a significant role of AtPDAT1 in plants responses to both biotic and abiotic stresses, highlighting its potential as a target for further research.