Nitric Oxide and Abscisic Acid Mediate Heat Stress Tolerance through Regulation of Osmolytes and Antioxidants to Protect Photosynthesis and Growth in Wheat Plants.

Noushina Iqbal,Mehar Fatma,Adriano Sofo,Shahid Umar,Zebus Sehar,Nafees A Khan

doi:10.3390/antiox11020372

Noushina Iqbal, Mehar Fatma + Show 4 more

Open Access

https://doi.org/10.3390/antiox11020372

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Abstract

Nitric oxide (NO) and abscisic acid (ABA) play a significant role to combat abiotic stress. Application of 100 µM sodium nitroprusside (SNP, NO donor) or ABA alleviated heat stress effects on photosynthesis and growth of wheat (Triticum aestivum L.) plants exposed to 40 °C for 6 h every day for 15 days. We have shown that ABA and NO synergistically interact to reduce the heat stress effects on photosynthesis and growth via reducing the content of H2O2 and thiobarbituric acid reactive substances (TBARS), as well as maximizing osmolytes production and the activity and expression of antioxidant enzymes. The inhibition of NO and ABA using c-PTIO (2-4 carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and fluridone (Flu), respectively, reduced the osmolyte and antioxidant metabolism and heat stress tolerance. The inhibition of NO significantly reduced the ABA-induced osmolytes and antioxidant metabolism, exhibiting that the function of ABA in the alleviation of heat stress was NO dependent and can be enhanced with NO supplementation.Thus, regulating the activity and expression of antioxidant enzymes together with osmolytes production could act as a possible strategy for heat tolerance.

Highlights

IntroductionThe rise in temperature beyond the plants’ optimal requirement for growth is one of the most serious abiotic stressors causing irreparable harm to the development of plants [1,2]
As the hormonal action is interrelated through a cascade of signaling molecules, we have shown the coordination of Nitric oxide (NO) and abscisic acid (ABA) in heat stress tolerance, with major emphasis on osmolytes and antioxidants
SNP and/or ABA in the presence (40 ◦ C) or absence (25 ◦ C) of heat stress at 30 days after sowing (DAS).The combined NO and ABA treatment under heat stress was subjected to 100 μM cPTIO

Summary

Introduction

The rise in temperature beyond the plants’ optimal requirement for growth is one of the most serious abiotic stressors causing irreparable harm to the development of plants [1,2]. Climate change is expected to significantly affect agriculture and food security [3]. It has been estimated that a gradual expected rise in the global temperature may influence plant productivity prominently, in the decades [4]. The average world temperature over the 20 years may reach or exceed 1.5 ◦ C of warming. At 2 ◦ C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health according to the Intergovernmental Panel on Climate Change [5]

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