Nitric Oxide and Hydrogen Sulfide Coordinately Reduce Glucose Sensitivity and Decrease Oxidative Stress via...

Area of Science:

• Plant Physiology
• Biochemistry
• Environmental Stress Biology

Background:

• Heat stress (HS) impairs plant photosynthesis, partly due to increased glucose levels.
• Nitric oxide (NO) and hydrogen sulfide (H₂S) are signaling molecules involved in plant stress responses.

Purpose of the Study:

• To investigate the roles of NO and H₂S in mitigating heat-induced photosynthetic inhibition in wheat (Triticum aestivum L.).
• To elucidate the interaction between NO and H₂S in enhancing heat tolerance.

Main Methods:

• Wheat plants were subjected to heat stress (40 °C) and recovery (25 °C).
• Treatments included sodium nitroprusside (SNP, NO donor) and sodium hydrosulfide (NaHS, H₂S donor), with and without scavengers (cPTIO for NO, hypotaurine for H₂S).
• Photosynthetic ability, glucose content, oxidative stress markers (H₂O₂, TBARS), and ascorbate-glutathione metabolism were assessed.

Main Results:

• HS increased glucose content and repressed photosynthesis, accompanied by oxidative stress.
• SNP and NaHS treatments reduced glucose-mediated photosynthetic suppression and oxidative damage.
• Combined SNP and NaHS treatment provided maximum protection, indicating synergistic effects.
• H₂S scavenging diminished NO-mediated alleviation, suggesting downstream action of H₂S in NO signaling.
• Simultaneous scavenging of both NO and H₂S negated the protective effects.

Conclusions:

• NO and H₂S cooperate to enhance wheat photosynthesis under heat stress.
• Their protective mechanism involves reducing H₂O₂-induced oxidative stress and excess glucose-mediated photosynthetic suppression.
• H₂S likely acts downstream in the NO-mediated pathway for heat tolerance.