Melatonin Seed Priming Improves Chlorophyll content under High Temperature Stress by Modulating Heat Responsive Genes in Wheat (Triticum aestivum L.)

Author: Shaziya Sultana and Sharmistha Barthakur

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Abstract

Extreme temperature swings and a sharp decline in crop productivity brought on by global climate change contribute to global food insecurity. One of the biggest barriers to plant growth and development is high temperature, profoundly impact plant physiology, biochemistry, and molecular processes. Biostimulants melatonin (MT), which serves as a "defence molecule" to protect the body, have a multifunctional purpose. Melatonin (MT) is a pleiotropic signaling molecule which positively modulates the effects of different environmental stressors including heat stress (HS). Heat stress Here, to analyze the effect of melatonin in modulating the chlorophyll content we carried out transcript expression profiling of heat marker genes heat shock protein 70 (Hsp70) and antioxidant enzyme gene superoxide dismutase (SOD) under ambient as well as high temperature stress. Seeds of wheat cv HD2967 were primed with a series of melatonin at MT1 (15 mgl-1), MT2 (30 mgl-1), MT3 (50 mgl-1), MT4 (60 mgl-1), and MT5 (75 mgl-1) and water alone as control. MT3 (50 mgl-1), and MT4 (60 mgl-1) remarkably improved the chlorophyll content. Further, seeds primed with (50 mgl-1) were given heat stress at 37°C for 4hrs and analysed for heat effect on chlorophyll. Results show the effectiveness of MT in enhancing chlorophyll content and induced expression of heat related genes under ambient as well as after high temperature exposure.

Keywords

Melatonin, Seed priming, Wheat, Chlorophyll, germination, HSP70, SOD

Conclusion

Based on the experimental findings, we conclude that melatonin seed priming differentially regulated and positively improved the germination indices and other physiological processes. Pre-treatment of melatonin at 50 mgl-1 and 60mgl-1 was found significant in improving chlorophyl content. Our study concluded that melatonin has potential role to improve chlorophyll content under different concentration with 50mgl-1 being an optimum value to sustain photosynthetic efficiency. At the molecular level transcript expression of Hsp70 showed similar level under different melatonin concentration. At the specific concentrations of melatonin (50mgl-1 and 60mgl-1) can positively improve chlorophyll concentration. The seeds primed with 50mgl-1 was given heat stress and further compared with control seedlings and positive effect of melatonin was recorded. The expression of SOD enzyme gene, an antioxidant enzyme was increased under melatonin priming as compared to no priming under heat stress condition. Chlorophyll content also improved in primed condition under heat stress, hence improving the photosynthetic capacity. This study provides a valuable base in showing the protective role melatonin in germination and seedling growth of wheat under normal and heat stress environment.

References

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How to cite this article

Shaziya Sultana and Sharmistha Barthakur (2023). Melatonin Seed Priming Improves Chlorophyll content under High Temperature Stress by Modulating Heat Responsive Genes in Wheat (Triticum aestivum L.). Biological Forum – An International Journal, 15(5a): 362-367.