Sugar Transporters, Sugar-Metabolizing Enzymes, and Their Interaction with Phytohormones in Sugarcane

Carbohydrates, particularly sucrose in the sugarcane crop, are of much value and are required in a number of metabolic activities. Sucrose production and accumulation along with sucrose processing and mechanism in sugarcane have been elaborately studied. Enzymes and hormones have an important role and function in this perspective. The four metabolizing sugar enzymes (sucrose phosphate synthase, sucrose synthase, sucrose phosphate phosphatase, invertase) and eight phytohormones (auxin, abscisic acid, cytokinin, salicylic acid, gibberellic acid, ethylene, brassinosteroids, and jasmonic acid) play a pivotal crucial role in sucrose biosynthesis and accumulation in sugarcane. Their interaction with sugar transporters at certain checkpoints is even equally important. The allocation of sugars requires a source-sink dynamics wherein the importance of sucrose loading and unloading in phloem tissue involves the use of different sugar transporters. These sugar transporters have influenced the sugarcane survival capability at the severe, moderate and mild impact of abiotic (like drought) and biotic (like diseases) stresses. Their interaction with enzymes and phytohormones has contributed to the tolerance potential of sugarcane. In this review, we focus on the sucrose production and storage process and the involvement of phytohormones in sugarcane under normal and abiotic stress conditions. Furthermore, the various sugar metabolizing enzymes and different sugar transporters have been identified in sugarcane and their significance has also been described in brief.