Kinetin modulates physio-hormonal attributes and isoflavone contents of Soybean grown under salinity stress

Abstract

Crop productivity continues to decline due to a wide array of biotic and abiotic stresses. Salinity is one of the worst abiotic stresses, as it causes huge losses to crop yield each year. Kinetin (Kn) has been reported as plant growth regulator since long, but its role in improving plant growth and food quality under saline conditions through mediating phytohormonal cross-talk is poorly studied. Current study was designed to evaluate the impact of exogenously applied Kn on growth, isoflovones and endogenous phytohormones of soybean grown under NaCl induced salt stress. Soybean plants were grown in perlite (semi hydroponic), and under controlled green-house conditions. Elevated levels of exogenous Kn significantly mitigated the adverse effect of NaCl and rescued plant growth attributes, i.e., plant height, fresh and dry biomass of soybean plants grown in all treatments. Higher diadzen, glycitin, and genistin contents were observed in plants treated with elevated Kn in the presence or absence of NaCl induce salt stress. The gibberellins (GAs) biosynthesis pathway was up-regulated by Kn as the bioactive GA1 and GA4 contents were significantly higher in Kn treated plants, as compared to control, while GAs level reduced in NaCl treated plants. Contrary to GAs, the abscisic acid contents declined with Kn but promoted in NaCl stressed soybean plants. The endogenous jasmonic acid and salicylic acid contents of soybean enhanced with elevated Kn application, but they showed an antagonistic response under salt stress. Current study supports the active role of Kn to ameliorate the adverse effects of salt stress on the growth and food quality of soybean. The favorable role of Kn toward soybean growth under salt stress may be attributed to its potential to modulate cross-talk between the various phytohormones involved in soybean growth and its resistance to salinity stress.

Exogenous Kinetin Promotes the Nonenzymatic Antioxidant System and Photosynthetic Activity of Coffee (Coffea arabica L.) Plants Under Cold Stress Conditions

“…The kinetin-hydrogen peroxide-mediated reinforcement of the antioxidant system is supported by high amounts of antioxidant compounds analyzed in the current study (Figures 3-5). The current results are in agreement with several reports were exogenous kinetin treatment increased the tolerance of plants to abiotic stress conditions through the increased activities of antioxidant enzymes [34][35][36]52], as well as the increased contents of several antioxidant compounds, such as flavonoids, gibberellins, salicylic acid, jasmonic acid and abscisic acid in salinity-stressed soybean plants [37], proline in drought-stressed rice [39], salvianolic acid and rosmarinic acid in Dracocephalum forrestii [40]. Although the accumulation of several secondary metabolites in the leaves of coffee plants under oxidative stress conditions is a well-known phenomenon [15,16], this study is the first to report a profound increment in the contents of these compounds in response to exogenous kinetin treatment under optimal or cold stress conditions.…”

“…Amongst the cytokinins, kinetin (N 6 -furfuryladenine), a compound first isolated from autoclaved herring sperm DNA [33], recently received tremendous attention for its oxidative stress mitigation and growth promotion effects [34][35][36]. Moreover, due to its abundance amongst the cytokinins, its commercial applications, particularly in agricultural science, has been implored [37]. The exogenous foliar application of kinetin with concentrations ranging from 0.01 mM to 2 mM has been reported to increase the growth rate, yield, crop quality and tolerance to abiotic stress conditions, such as salinity, heavy metal stress and drought, among others in several crops [29,34,[36][37][38].…”

“…Moreover, due to its abundance amongst the cytokinins, its commercial applications, particularly in agricultural science, has been implored [37]. The exogenous foliar application of kinetin with concentrations ranging from 0.01 mM to 2 mM has been reported to increase the growth rate, yield, crop quality and tolerance to abiotic stress conditions, such as salinity, heavy metal stress and drought, among others in several crops [29,34,[36][37][38]. Although the mechanism of kinetin action in mitigating oxidative stresses is not yet clearly understood, it has been suggested that kinetin upregulates both the enzymatic and the nonenzymatic antioxidative systems, hence reinforcing the ROS scavenging abilities of plants [34].…”

“…Although the mechanism of kinetin action in mitigating oxidative stresses is not yet clearly understood, it has been suggested that kinetin upregulates both the enzymatic and the nonenzymatic antioxidative systems, hence reinforcing the ROS scavenging abilities of plants [34]. The exogenous foliar application of kinetin activates and stimulates the biosynthesis of secondary metabolites through the upregulation of the corresponding transcripts or by increasing the activities of the biosynthetic enzymes in a number of plants [37,39,40]. Therefore, due to the repressed enzyme activity during cold stress conditions, amplification of the nonenzymatic antioxidative system through kinetin application might offer a necessary tolerance mechanism to enhance the growth of plants, such as coffee.…”

Potential of exogenously sourced kinetin in protecting Solanum lycopersicum from NaCl-induced oxidative stress through up-regulation of the antioxidant system, ascorbate-glutathione cycle and glyoxalase system

“…Recently, KN has been reported to enhance salt tolerance in soybean through its interaction with other growth hormones [13]. Exogenous application of plant growth hormones, such as cytokinins, has been shown to enhance the yield potential of agricultural crops under field conditions [14–16].…”