CDPKs Based Signalling Network: Protecting the Wheat from Heat

Wheat, being a staple food grain crop, is highly sensitive to terminal heat stress. The mechanism underlying heat stress tolerance in wheat has yet not been elucidated. Diverse signalling networks has been adopted by the plants in order to regulate their biological functions and protect the cells from the vageries of nature. Out of all the signalling pathways known and characterized, Ca2+ − secondary messenger-linked pathways are very predominant in different biological functions. Calcium Dependent Protein Kinases, showed the presence of N-terminal domain (which is variable), a protein kinase domain (shows phosphorylation activity), an auto-inhibitory region, and a calmodulin-like domain with EF-hand Ca2+-binding sites. CDPKs has been reported to acts as temperature sensing device or thermometer for the plants. It plays very important role in the regulation of guard cells and in ABA-regulated stomatal signalling in Arabidopsis. OsCDPK7 and OsCDPK13 present in rice have been reported to modulate the tolerance level against cold, salt, and drought stresses. CDPKs have also been reported to involved in ROS homeostasis and protection of cells against abiotic stresses. CDPKs has also been observed to modualte the carbon fixation process under adverse conditions. The actual sensory and signalling molecules and/or the primary targets of CPKs mediated regulation of photosynthesis and carbon assimilation metabolism under heat stress are still unclear. It is worthwhile to examine the role of CDPKs in altering the photosynthesis and source-to-sink carbon transfer in wheat under heat stress.