11 - Regulation of transporters through different exogenously applied chemicals during environmental stress

Abstract

Abiotic stresses like metals, salinity, UV-B radiation, extreme temperatures, and drought are major threats for agricultural systems and yield of crop plants. They regulate the plant physiology and metabolism by various ways via changing of various biochemical mechanisms. One of the biochemical mechanisms to combat such environmental stresses is upregulation of transporters by the application of external chemicals that may induce the synthesis of various other internal metabolites, phytohormones, and ions. A plant cell has various membrane-bound and subcellular organelle-based transporters such as active transporters and channels. The active transporters, such as the cation diffusion facilitator and the ABC transporters, are energy dependent for metal tolerance, whereas channels facilitate transport of a solute in a passive mode, for example, aquaporins (AQP), which are known to transport water and many other small solutes. Such transporters have a prominent role in internal homeostasis of metal, which play a pivotal role in various abiotic stress tolerances. The ionic stress is signaled via specific signaling pathways, for example, a specific SOS pathway controls the expression and activity of ion transporters. The exogenous or external applications of phytoprotectants or the chemicals to protect the plant physiology and metabolisms during abiotic stresses regulate plant homoeostasis as osmoprotectants and has been found to be effective in mitigating various oxidative stress-related damages induced during various abiotic stress conditions in plants by employing ion transporters. Some internal secondary metabolite and special ions have shown positive effects on the physiology, yield, and growth parameters in plants. Plant light signaling cascade (including UV radiation) include upregulation oftransport-related genes like ATP-dependent transporters and sugar transporters. In this chapter, the role of exogenously applied chemicals to combat various environmental abiotic stresses via regulation of transporters is discussed.