Reactive oxygen species scavenging mechanisms associated with polyethylene glycol mediated osmotic stress tolerance in Chinese potato

Abstract

Influence of polyethylene glycol (PEG) mediated osmotic stress on reactive oxygen species (ROS) scavenging machinery of Chinese potato (Solenostemon rotundifolius (Poir.) J. K. Morton) was investigated. Five genotypes of Chinese potato were raised in Murashige and Skoog (MS) basal medium containing 6-benzylaminopurine (BAP, 1 mg L-1) along with various concentrations of PEG-6000 mediated stress conditions (0,-0.2 and-0.5 MPa) and evaluated for osmotic stress tolerance in vitro. The medium containing PEG-6000 had a detrimental effect on plantlet growth and development while compared with the control. Accumulation of H 2 o 2 was lower in Sreedhara and Subala and higher in Nidhi under PEG stress, which was evident by in situ detection in leaves. Lipid peroxidation product such as malondialdehyde (MDA) content was increased due to PEG stress which was more in susceptible genotype than that in tolerant ones. An enhanced ROS-scavenging antioxidant enzyme was observed under stress with respect to the control. The enzymes of ascorbate-glutathione cycle showed an important role in scavenging ROS. The imposition of PEG stress also increased the non-enzymatic antioxidants viz., the ascorbate and reduced glutathione content which was prominent in tolerant genotypes in comparison to susceptible. The present study indicated that, Sreedhara and Subala showed more tolerance to osmotic stress with better ROS scavenging machineries which would be the lines of interest for augmenting future breeding strategies in this climate resilient minor tuber crop. Chinese potato (Solenostemon rotundifolius (Poir.) J. K. Morton), belongs to the family Lamiaceae, is one of the important minor tuber crops grown in the tropics of the world. The tubers of this crop are rich in carbohydrates and minerals 1 which provide essential dietary and energy supplements during the lean periods. It could be the better alternative to potato (Solanum tuberosum L.) for the tropics of the world under changing climatic conditions; where potato fails to grow due to global warming. Chinese potato can grow in a wide range of environmental conditions. Despite its wide adaptability, the productivity (18-20 t/ha) was severely affected due to osmotic stress. Under natural conditions, plant growth and development often challenged by various stresses 2 , of which, osmotic stress is one of the most limiting factors which can cause 20-98% of yield reductions 3. To elucidate the plant response to osmotic stress, in vitro cultures are preferred as it minimizes nutrient and environmental variations under control conditions 4. In this investigation, we have used polyethylene glycol (PEG-6000) to induce osmotic stress conditions in vitro. In plant osmotic stress studies, PEG is widely used as a potential osmoticum in the nutrient medium to induce water deficit 5. Induced osmotic stress resulted in overproduction of reactive oxygen species (ROS) which was considered as a hallmark of plant stress response. To scavenge the toxic consequences of ROS, plant deploys antioxidative mecha...

Salinity Stress in Potato: Understanding Physiological, Biochemical and Molecular Responses

“…The higher Na + concentration in the plant leads to inhibit the uptake of K + ions, which is one of the essential mineral elements for growth and development [73]. In response to the imbalance of ionic concentration in the cell, it undergoes salinity stress, leading to ROS production, such as singlet oxygen, hydrogen peroxide, and superoxide radicals, which further interrupt the vital cellular functions of the potato plant [21,74,75]. The ionic homeostasis is maintained under salt stress by adjusting K + and Na + ions by their acquisition and distribution in plants.…”

Drought-hardening improves drought tolerance in Nicotiana tabacum at physiological, biochemical, and molecular levels

“…Previous studies documented the role of AsA and GSH in ROS scavenging in wheat [60] and potato [61]. A previous study had shown that drought priming induced the non-antioxidant defense system (AsA and GSH contents) to mitigate the harmful effects of ROS [62].…”

Studying The Responses of Hordeum vulgare Seedlings to Salinity and Osmotic Stresses: Oxidative Stress/Antioxidants Play Crucial Roles دراسة إستجابات بادرات الشعير للإجهاد الملحي والأسموزي: الإجهاد بالأکسدة ومضاداتها يلعبان دورا هاما

“…This phenomenon suggests that osmotic stress by PEG served as an environmental signal factor for induction of the non-enzymatic antioxidant mechanism. Likewise, the application of PEG has increased AsA and GSH in tolerant genotypes of Chinese potato (Sahoo et al, 2020). On the other hand, application of PEG possessed a stimulatory effect on GSH content by 113.5%, whilst NaCl has provoked GSH by 32.0% compared to control.…”

“…The higher levels of H2O2 and MDA recorded under PEG treatment suggested that the extent of oxidative injury is much higher than defense mechanisms. According to Sahoo et al (2020), PEG mediated osmotic stress resulted in oxidative burst in Chinese potato genotypes as evident by accumulation of MDA as well as H2O2 in vitro. Such results is consistent with Lan et al (2020), who found high induction of MDA in PEG treatments, whilst stable MDA levels in NaCl-treated seedlings were recorded.…”