AUTHOR=Demski Kamil , Łosiewska Anna , Jasieniecka-Gazarkiewicz Katarzyna , Klińska Sylwia , Banaś Antoni 

TITLE=Phospholipid:Diacylglycerol Acyltransferase1 Overexpression Delays Senescence and Enhances Post-heat and Cold Exposure Fitness

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.611897

DOI=10.3389/fpls.2020.611897

ISSN=1664-462X

ABSTRACT=<p>In an alternative pathway to acyl-CoA: diacylglycerol acyltransferase (DGAT)-mediated triacylglycerol (TAG) synthesis from diacylglycerol, phospholipid:diacylglycerol acyltransferase (PDAT) utilizes not acyl-CoA but an acyl group from sn-2 position of a phospholipid, to form TAG. The enzyme’s activity <italic>in vitro</italic> matches DGAT’s in a number of plant species, however its main function in plants (especially in vegetative tissue) is debatable. In the presented study, we cultivated <italic>PDAT1</italic>-overexpressing, <italic>pdat1</italic> knockout and wild-type lines of <italic>Arabidopsis thaliana</italic> through their whole lifecycle. <italic>PDAT1</italic> overexpression prolonged Arabidopsis lifespan in comparison to wild-type plants, whereas knocking out <italic>pdat1</italic> accelerated the plant’s senescence. After subjecting the 3-week old seedlings of the studied lines (grown <italic>in vitro</italic>) to 2-h heat stress (40°C) and then growing them for one more week in standard conditions, the difference in weight between wild-type and <italic>PDAT</italic>1-overexpressing lines increased in comparison to the difference between plants grown only in optimal conditions. In another experiment all lines exposed to 2-week cold stress experienced loss of pigment, except for <italic>PDAT</italic>1-overexpressing lines, which green rosettes additionally weighed 4 times more than wild-type. Our results indicate that plants depleted of <italic>PDAT1</italic> are more susceptible to cold exposure, while <italic>PDAT1</italic> overexpression grants plants a certain heat and cold resilience. Since it was shown, that lysophospholipids may be intertwined with stress response, we decided to also conduct <italic>in vitro</italic> assays of acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) and acylCoA:lysophosphatidylethanolamine acyltransferase (LPEAT) activity in microsomal fractions from the <italic>PDAT1</italic>-overexpressing Arabidopsis lines in standard conditions. The results show significant increase in LPEAT and LPCAT activity in comparison to wild-type plants. <italic>PDAT1</italic>-overexpressing lines’ rosettes also present twice as high expression of <italic>LPCAT2</italic> in comparison to control. The presented study shows how much heightened expression of <italic>PDAT1</italic> augments plant condition after stress and extends its lifespan.</p>