AUTHOR=Annum Nazish , Ahmed Moddassir , Imtiaz Khadija , Mansoor Shahid , Tester Mark , Saeed Nasir A. 

TITLE=32Pi Labeled Transgenic Wheat Shows the Accumulation of Phosphatidylinositol 4,5-bisphosphate and Phosphatidic Acid Under Heat and Osmotic Stress

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.881188

DOI=10.3389/fpls.2022.881188

ISSN=1664-462X

ABSTRACT=<p>The ensuing heat stress drastically affects wheat plant growth and development, consequently compromising its grain yield. There are many thermoregulatory processes/mechanisms mediated by ion channels, lipids, and lipid-modifying enzymes that occur in the plasma membrane and the chloroplast. With the onset of abiotic or biotic stresses, phosphoinositide-specific phospholipase C (PI-PLC), as a signaling enzyme, hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP<sub>2</sub>) to generate inositol 1,4,5-trisphosphate (IP<sub>3</sub>) and diacylglycerol (DAG) which is further phosphorylated into phosphatidic acid (PA) as a secondary messenger and is involved in multiple processes. In the current study, a phospholipase C (PLC) signaling pathway was investigated in spring wheat (<italic>Triticum aestivum</italic> L.) and evaluated its four <italic>AtPLC5</italic> overexpressed (OE)/transgenic lines under heat and osmotic stresses through <sup>32</sup>P<sub>i</sub> radioactive labeling. Naturally, the wheat harbors only a small amount of PIP<sub>2</sub>. However, with the sudden increase in temperature (40°C), PIP<sub>2</sub> levels start to rise within 7.5 min in a time-dependent manner in wild-type (<italic>Wt</italic>) wheat. While the Phosphatidic acid (PA) level also elevated up to 1.6-fold upon exposing wild-type wheat to heat stress (40°C). However, at the anthesis stage, a significant increase of ∼4.5-folds in PIP<sub>2</sub> level was observed within 30 min at 40°C in <italic>AtPLC5</italic> over-expressed wheat lines. Significant differences in PIP<sub>2</sub> level were observed in <italic>Wt</italic> and <italic>AtPLC5-OE</italic> lines when treated with 1200 mM sorbitol solution. It is assumed that the phenomenon might be a result of the activation of PLC/DGK pathways. Together, these results indicate that heat stress and osmotic stress activate several lipid responses in wild-type and transgenic wheat and can explain heat and osmotic stress tolerance in the wheat plant.</p>