AUTHOR=Annum Nazish , Ahmed Moddassir , Tester Mark , Mukhtar Zahid , Saeed Nasir Ahmad 

TITLE=Physiological responses induced by phospholipase C isoform 5 upon heat stress in Arabidopsis thaliana

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1076331

DOI=10.3389/fpls.2023.1076331

ISSN=1664-462X

ABSTRACT=<p>Plant’s perception of heat stress involves several pathways and signaling molecules, such as phosphoinositide, which is derived from structural membrane lipids phosphatidylinositol. Phospholipase C (PLC) is a well-known signaling enzyme containing many isoforms in different organisms. In the present study, Phospholipase C Isoform 5 (<italic>PLC5</italic>) was investigated for its role in thermotolerance in <italic>Arabidopsis thaliana</italic>. Two over-expressing lines and one knock-down mutant of <italic>PLC5</italic> were first treated at a moderate temperature (37 °C) and left for recovery. Then again exposed to a high temperature (45 °C) to check the seedling viability and chlorophyll contents. Root behavior and changes in <sup>32</sup>P<sub>i</sub> labeled phospholipids were investigated after their exposure to high temperatures. Over-expression of <italic>PLC5</italic> (<italic>PLC5 OE</italic>) exhibited quick and better phenotypic recovery with bigger and greener leaves followed by chlorophyll contents as compared to wild-type (<italic>Col-0</italic>) and <italic>PLC5</italic> knock-down mutant in which seedling recovery was compromised. <italic>PLC5</italic> knock-down mutant illustrated well-developed root architecture under controlled conditions but stunted secondary roots under heat stress as compared to over-expressing <italic>PLC5</italic> lines. Around 2.3-fold increase in phosphatidylinositol 4,5-bisphosphate level was observed in <italic>PLC5 OE</italic> lines upon heat stress compared to wild-type and <italic>PLC5</italic> knock-down mutant lines. A significant increase in phosphatidylglycerol was also observed in <italic>PLC5 OE</italic> lines as compared to <italic>Col-0</italic> and <italic>PLC5</italic> knock-down mutant lines. The results of the present study demonstrated that <italic>PLC5</italic> over-expression contributes to heat stress tolerance while maintaining its photosynthetic activity and is also observed to be associated with primary and secondary root growth in <italic>Arabidopsis thaliana</italic>.</p>