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

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 (PLC5) was investigated for its role in thermotolerance in Arabidopsis thaliana. Two over-expressing lines and one knock-down mutant of PLC5 were first treated at a moderate temperature (37 degrees C) and left for recovery. Then again exposed to a high temperature (45 degrees C) to check the seedling viability and chlorophyll contents. Root behavior and changes in P-32(i) labeled phospholipids were investigated after their exposure to high temperatures. Over-expression of PLC5 (PLC5 OE) exhibited quick and better phenotypic recovery with bigger and greener leaves followed by chlorophyll contents as compared to wild-type (Col-0) and PLC5 knock-down mutant in which seedling recovery was compromised. PLC5 knock-down mutant illustrated well-developed root architecture under controlled conditions but stunted secondary roots under heat stress as compared to over-expressing PLC5 lines. Around 2.3-fold increase in phosphatidylinositol 4,5-bisphosphate level was observed in PLC5 OE lines upon heat stress compared to wild-type and PLC5 knock-down mutant lines. A significant increase in phosphatidylglycerol was also observed in PLC5 OE lines as compared to Col-0 and PLC5 knock-down mutant lines. The results of the present study demonstrated that PLC5 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 Arabidopsis thaliana.

Automated summary

This study investigated the role of Phospholipase C Isoform 5 (PLC5) in thermotolerance in Arabidopsis thaliana. The results showed that over-expression of PLC5 contributes to heat stress tolerance and maintains photosynthetic activity, with effects on root development.