Abstract

Nitric oxide (NO) has emerged as a key molecule involved in many physiological processes in plants. To characterize roles of NO in tolerance of Arabidopsis (Arabidopsis thaliana) to salt stress, effect of NaCl on Arabidopsis wild-type and mutant (Atnoa1) plants with an impaired in vivo NO synthase (NOS) activity and a reduced endogenous NO level was investigated. Atnoa1 mutant plants displayed a greater Na+ to K+ ratio in shoots than wild-type plants due to enhanced accumulation of Na+ and reduced accumulation of K+ when exposed to NaCl. Germination of Atnoa1 seeds was more sensitive to NaCl than that of wild-type seeds, and wild-type plants exhibited higher survival rates than Atnoa1 plants when grown under salt stress. Atnoa1 plants had higher levels of hydrogen peroxide than wild-type plants under both control and salt stress, suggesting that Atnoa1 is more vulnerable to salt and oxidative stress than wild-type plants. Treatments of wild-type plants with NOS inhibitor and NO scavenger reduced endogenous NO levels and enhanced NaCl-induced increase in Na+ to K+ ratio. Exposure of wild-type plants to NaCl inhibited NOS activity and reduced quantity of NOA1 protein, leading to a decrease in endogenous NO levels measured by NO-specific fluorescent probe. Treatment of Atnoa1 plants with NO donor sodium nitroprusside attenuated the NaCl-induced increase in Na+ to K+ ratio. Therefore, these findings provide direct evidence to support that disruption of NOS-dependent NO production is associated with salt tolerance in Arabidopsis.

Highlights

  • Nitric oxide (NO) has emerged as a key molecule involved in many physiological processes in plants

  • We showed that the NO synthase (NOS) activity measured by the standard Cayman kit protocol was in agreement with that measured by measuring citrulline with the HPLC

  • There are some debates on the nature of NOA1 (NOS1; Crawford et al, 2006; Guo, 2006; Zemojtel et al, 2006), our results clearly highlight that Atnoa1 mutants are of valuable materials in studying the physiological functions of NO in plants

Read more

Summary

Introduction

Nitric oxide (NO) has emerged as a key molecule involved in many physiological processes in plants. To characterize roles of NO in tolerance of Arabidopsis (Arabidopsis thaliana) to salt stress, effect of NaCl on Arabidopsis wild-type and mutant (Atnoa1) plants with an impaired in vivo NO synthase (NOS) activity and a reduced endogenous NO level was investigated. Treatments of wild-type plants with NOS inhibitor and NO scavenger reduced endogenous NO levels and enhanced NaCl-induced increase in Na1 to K1 ratio. Treatment of Atnoa plants with NO donor sodium nitroprusside attenuated the NaCl-induced increase in Na1 to K1 ratio These findings provide direct evidence to support that disruption of NOSdependent NO production is associated with salt tolerance in Arabidopsis. Involvement of Nitric Oxide in Salt Stress in Arabidopsis enzymes include superoxide dismutase, ascorbate peroxidase (POD), catalase, and POD. To characterize the role of NO in salt stress, we studied responses of loss-offunction mutant Atnoa to moderate salt stress and compared with those of Arabidopsis wild-type plants

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call