An overview and recent progress of plant growth regulators (PGRs) in the mitigation of abiotic stresses in fruits: A review

Abstract

Plant growth regulators are organic chemical compounds that alter or regulate various physiological processes appreciably in a plant when used in small concentrations. These plant growth regulators have become an integral component of agro-technical procedures for most plants cultivated and particularly for fruit plants. Fruits are regarded as a highly valuable crop because of their significance in the uplift of the country's economy as well as their crucial role in providing a wide range of health benefits. However, multiple environmental stressors such as drought, salinity, cold, and heat stress, as well as other detrimental factors, have a deleterious effect on the quality of fruit crops around the globe. Among them, salinity stress is a significant constraint to fruit plant growth, yield and biomass production. For instance, exogenous treatments of plant growth regulators like abscisic acid, gibberellins, ethylene, auxin, jasmonic acid, brassinosteroids, salicylic acid, strigolactones, nitric oxide and others that are not recognized as PGRs like polyamines are effective in alleviating the negative impacts of abiotic stress on fruit crops throughout the pre-harvest and post-harvest periods. Furthermore, they not only affect the internal physiology of fruits but are equally significant to fruit set, yield, quality and retention. Therefore, in this review, we have discussed the current breakthroughs in PGR application and their impact on fruit crops, with a focus on their role in alleviating abiotic stresses. Moreover, we also highlighted their complex biosynthesis and signaling pathways during abiotic stress responses. To contextualize, the integration of recent scientific advances will have a substantial impact on fruit yield and quality.