Abstract
Effect of triacontanol on drought-induced stress was studied in Brassica juncea L. Foliage of sixteen-days-old plants was sprayed with concentrations (0, 10, 20 and 30 μM) of triacontanol (TRIA) for 7 days. Subsequently, plants were subjected to drought stress (10% polyethylene glycol, PEG6000) for 7 days. Drought stress increased oxidative stress (TBARS, O2●- and H2O2), however, their contents were reduced by TRIA. Total soluble sugars, reduced glutathione, and proline content in stressed plants were increased by TRIA. Activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), and phenylalanine ammonia-lyase (PAL) activity were significantly increased in a dose-dependent manner with TRIA. Potassium (K+) level declined, while magnesium (Mg2+) and calcium (Ca2+) contents increased. The elevated level of lignin under drought with TRIA was significantly associated with MYB46 and PAL gene expression patterns. Altogether, our results suggest that foliar spray of 20 μM TRIA was more operative in reducing the negative impact of drought stress in B. juncea by regulating the antioxidant system, calcium, and lignification.
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•Negative impact of drought attenuated by exogenous Triacontanol (TRIA) in Brassica juncea.•TRIA upholds the equilibrium between ROS generation and scavenging.•TRIA promote glutathione reductase activity, proline and calcium accumulation.•TRIA was able to increase phenylalanine ammonia lyase (PAL) activity and lignin content.•Under drought, TRIA increased MYB46 and PAL gene transcripts.