Targeting Glycinebetaine for Abiotic Stress Tolerance in Crop Plants: Physiological Mechanism, Molecular Interaction and Signaling

Abstract

In the era of climate change, abiotic stresses (e.g., salinity, drought, extreme temperature, flooding, metal/metalloid(s), UV radiation, ozone, etc.) are considered as one of the most complex environmental constraints that restricts crop production worldwide. Introduction of stress-tolerant crop cultivars is the most auspicious way of surviving this constraint, and to produce these types of tolerant crops. Several bioengineering mechanisms involved in stress signaling are being adopted in this regard. One example of this kind of manipulation is the osmotic adjustment. The quarternary ammonium compound glycinebetaine (GB), also originally referred to as betaine is a methylated glycine derivative. Among the betaines, GB is the most abundant one in plants, which is mostly produced in response to dehydration caused by different abiotic stresses like drought, salinity, and extreme temperature. Glycinebetaine helps in decreased accumulation and detoxification of ROS, thereby restoring photosynthesis and reducing oxidative stress. It takes part in stabilizing membranes and macromolecules. It is also involved in the stabilization and protection of photosynthetic components, such as ribulose-1, 5-bisphosphate carboxylase/oxygenase, photosystem II and quarternary enzyme and protein complex structures under environmental stresses. Glycinebetaine was found to perform in chaperone-induced protein disaggregation. In addition, GB can confer stress tolerance in very low concentrations, and it acts in activating defense responsive genes with stress protection. Recently, field application of GB has also shown protective effects against environmental adversities increasing crop yield and quality. In this review, we will focus on the role of GB in conferring abiotic stress tolerance and the possible ways to engineer GB biosynthesis in plants.

Incorporated Biochar-Based Soil Amendment and Exogenous Glycine Betaine Foliar Application Ameliorate Rice (Oryza sativa L.) Tolerance and Resilience to Osmotic Stress

“…For example, quantitative trait loci (QTLs) have been reported to play a key role in drought, flood, and salt tolerance in mega rice varieties [ 13 ]. Recently, soil amendment such as biochar and foliar spraying like glycine betaine has found its way into maintaining agricultural sustainable development, which has a great potential for enhancing the performance of crop yield and mitigating the environmental stress [ 28 , 29 ]. It has been suggested, with strong evidence, that biochar amendment is a promising approach to mitigate soil contamination via immobilizing heavy metals [ 30 ], improving overall soil quality [ 31 , 32 ], enhancing water–fertilizer productivity [ 31 ], and decreasing soil salinity [ 33 ] in arid [ 33 ] and semi-arid areas worldwide [ 31 , 32 ].…”

“…Furthermore, IAA-producing bacteria improves soil quality such as the soil physicochemical properties [ 52 ]. It has been proven, indeed, that biochar can boost dry matter production (root and leaves) as a consequence of its positive impact on osmolytes, chlorophyll pigments, and physiological traits [ 28 ]. These results are consistent with earlier reports such as those shown by Zhang et al [ 52 ].…”

Role of exogenous-applied salicylic acid, zinc and glycine betaine to improve drought-tolerance in wheat during reproductive growth stages

“…In addition, net photosynthesis, transpiration rate, and yield attributes were decreased under drought stress at the tillering, flowering, and milking stages in wheat plants, while exogenous application of GB enhanced them under drought treatment [ 19 , 39 ]. Similarly, Hasanuzzaman et al [ 40 ] recorded that GB played an important role in reducing aggregation and detoxification of ROS, hence recovering photosynthesis and decreasing oxidative stress. Our previous study, Shemi et al [ 22 ] have illustrated that exogenous applications of GB, Zn, and SA substantially improved the activity of CAT, SOD, and APX enzymes, and decreased the contents of MDA and H 2 O 2 , and these changes were beneficial to protect maize leaf tissues from oxidative harm in cell membranes.…”

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“…Moreover, intracellular levels of proline have been reported to act as a signaling/regulatory molecule able to activate multiple plant stress responses (Maggio et al, 2002). Proline along with GB seemed to protect plants from the negative effects of stress by stabilizing enzymes, such as, Rubisco, as also supported by Hasanuzzaman et al (2019). Both these osmoregulators accumulated to a greater extent in roots than leaves, indicating that pigeonpea roots experienced greater metal-induced osmotic stress due to higher accumulations of Cd/Zn.…”