Putrescine Plays a Positive Role in Salt-Tolerance Mechanisms by Reducing Oxidative Damage in Roots of Vegetable Soybean

Abstract

Polyamines play important roles in plant tolerance to environmental stress. With the aim of investigating the possible involvement of putrescine (Put) in salt-tolerance mechanisms in vegetable soybean roots, exogenous Put (10 mM) and its biosynthetic inhibitor D-arginine (D-Arg) (0.5 mM) were added to nutrient solution when vegetable soybean (Glycine max L. cv. Huning 95-1) seedlings were exposed to 100 mM sodium chloride (NaCl). The results showed that Put ameliorated but D-Arg aggravated the detrimental effects of NaCl on plant growth and biomass production. Under NaCl stress, levels of free, soluble conjugated, and insoluble bound types of Put in roots of vegetable soybean were reduced, whereas those of free, soluble conjugated, and insoluble bound types of spermidine (Spd) and spermine (Spm) were increased. Exogenous Put eliminated the decrease in Put but promoted the increase of Spd and Spm. However, these changes could be reversed by D-Arg. Under NaCl stress, activities of arginine decarboxylase (ADC), S-adenosylmethionine decarboxylase (SAMDC), diamine oxidase (DAO) and polyamine oxidase (PAO) were induced, with exogenous Put promoting and D-Arg reversing these changes. Furthermore, NaCl stress decreased activities of antioxidant enzymes.Exogenous Put alleviated but D-Arg exaggerated these effects of NaCl stress, resulting in the same changes in membrane damage and reactive oxygen species (ROS) production. These results indicate that Put plays a positive role in vegetable soybean roots by activating antioxidant enzymes and thereby attenuating oxidative damage.

Exogenous Spermidine Promotes γ-Aminobutyric Acid Accumulation and Alleviates the Negative Effect of NaCl Stress in Germinating Soybean (Glycine max L.)

“…The activities of major ROS detoxifying enzymes (SOD, POD, CAT, and GPX) increased significantly (p < 0.05) in germinating soybeans under Spd-NaCl treatment. This result is consistent with a study of other soybeans [23] and salt-responsive plants [14,24,25]. MDA and H2O2…”

A NAC Transcription Factor Represses Putrescine Biosynthesis and Affects Drought Tolerance

“…The importance of ADC and putrescine in abiotic stress tolerance is suggested by several lines of evidence. First, ADC gene transcripts and putrescine levels have been shown to be increased substantially by abiotic stresses in a range of plant species (Urano et al, 2004;Zhang et al, 2014). Second, elevated putrescine levels in plants via genetic engineering of the ADC gene were shown to improve stress tolerance.…”

Polyamines and legumes: Joint stories of stress, nitrogen fixation and environment

“…A significant number of additional works have analyzed the salt-induced changes in the PAs profiles of different legumes like soybean (Zhang et al, 2014), bean (López-Gómez et al, 2014aShevyakova et al, 2013;Talaat, 2015;Zapata et al, 2008), L. tenuis (Maiale et al, 2004;Sanchez et al, 2005;Sannazzaro et al, 2007). Taken together, these works do not show a congruent pattern of PAs changes due to saline treatment, not even within the same plant species,…”