Publications in the Year: 2022

Journal Article

AbdElgawad H, El-Sawah AM, Mohammed AE, Alotaibi MO, Yehia RS, Selim S, Saleh AM, Beemster GTS, Sheteiwy MS.  2022.  {Increasing atmospheric CO2 differentially supports arsenite stress mitigating impact of arbuscular mycorrhizal fungi in wheat and soybean plants}. Chemosphere. 296:134044. Abstract

Arbuscular mycorrhizal fungi (AMF) are beneficial for the plant growth under heavy metal stress. Such beneficial effect is improved by elevated CO2 (eCO2). However, the mechanisms by which eCO2 improves AMF symbiotic associations under arsenite (AsIII) toxicity are hardly studied. Herein, we compared these regulatory mechanisms in species from two agronomical important plant families – grasses (wheat) and legumes (soybean). AsIII decreased plant growth (i.e., 53.75 and 60.29% of wheat and soybean, respectively) and photosynthesis. It also increased photorespiration and oxidative injury in both species, but soybean was more sensitive to oxidative stress as indicated by higher H2O2 accumulation and oxidation of protein and lipid. eCO2 significantly improved AMF colonization by increasing auxin levels, which induced high carotenoid cleavage dioxygenase (CCDs) activity, particularly in soybean roots. The improved sugar metabolism in plant shoots by co-application of eCO2 and AsIII allocated more sugars to roots sequentially. Sugar accumulation in plant roots is further induced by AMF, resulting in more C skeletons to produce organic acids, which are effectively exudated into the soil to reduce AsIII uptake. Exposure to eCO2 reduced oxidative damage and this mitigation was stronger in soybean. This could be attributed to a greater reduction in photorespiration as well as a stronger antioxidant and detoxification defence systems. The grass/legume-specificity was supported by principal component analysis, which revealed that soybean was more affected by AsIII stress and more responsive to AMF and eCO2. This study provided a mechanistic understanding of the impact of AMF, eCO2 and their interaction on As-stressed grass and legume plants, allowing better practical strategies to mitigate AsIII phytotoxicity.
Zrig A, Saleh A, Hamouda F, Okla MK, Al-Qahtani WH, Alwasel YA, Al-Hashimi A, Hegab MY, Hassan AHA, AbdElgawad H.  2022.  {Impact of sprouting under potassium nitrate priming on nitrogen assimilation and bioactivity of three medicago species}. Plants. 11 Abstract

Edible sprouts are rich in flavonoids and other polyphenols, as well as proteins, minerals, and vitamins. Increasing sprout consumption necessitates improving their quality, palatability, and bioactivity. The purpose of this study was to test how KNO3 priming affects the sprouting process species on three Medicago species (Medicago indicus, Medicago interexta, and Medicago polymorpha) and their nutritional values. Targeted species of Medicago were primed with KNO3, and the levels of different primary and secondary metabolites were determined. KNO3 induced biomass accumulation in the sprouts of the three species, accompanied by an increased content of total mineral nutrients, pigments, vitamins, and essential amino acids. Besides, our results showed that KNO3 enhanced the activity of nitrate reductase (NR), glutamate dehydrogenase (GDH), and glutamine synthetase (GS) enzymes, which are involved in the nitrogen metabolism and GOGAT cycle, which, in turn, increase the nitrogen and protein production. KNO3 treatment improved the bioactive compound activities of Medicago sprouts by increasing total phenolic and flavonoid contents and enhancing the antioxidant and antidiabetic activities. Furthermore, species-specific responses toward KNO3 priming were noticeable, where Medicago interexta showed the highest antioxidant and antidiabetic activities, followed by Medicago polymorpha. Overall, this study sheds the light on the physiological and biochemical bases of growth, metabolism, and tissue quality improvement impact of KNO3 on Medicago sprouts.
Vinuganesh A, Kumar A, Prakash S, Alotaibi MO, Saleh AM, Mohammed AE, Beemster GTS, AbdElgawad H.  2022.  {Influence of seawater acidification on biochemical composition and oxidative status of green algae Ulva compressa}. Science of the Total Environment. 806:150445. AbstractWebsite

The sequestration of elevated atmospheric CO2 levels in seawater results in increasing acidification of oceans and it is unclear what the consequences of this will be on seaweed ecophysiology and ecological services they provide in the coastal ecosystem. In the present study, we examined the physiological and biochemical response of intertidal green seaweed Ulva compressa to elevated pCO2 induced acidification. The green seaweed was exposed to control (pH 8.1) and acidified (pH 7.7) conditions for 2 weeks following which net primary productivity, pigment content, oxidative status and antioxidant enzymes, primary and secondary metabolites, and mineral content were assessed. We observed an increase in primary productivity of the acidified samples, which was associated with increased levels of photosynthetic pigments. Consequently, primary metabolites levels were increased in the thalli grown under lowered pH conditions. There was also richness in various minerals and polyunsaturated fatty acids, indicating that the low pH elevated the nutritional quality of U. compressa. We found that low pH reduced malondialdehyde (MDA) content, suggesting reduced oxidative stress. Consistently we found reduced total antioxidant capacity and a general reduction in the majority of enzymatic and non-enzymatic antioxidants in the thalli grown under acidified conditions. Our results indicate that U. compressa will benefit from seawater acidification by improving productivity. Biochemical changes will affect its nutritional qualities, which may impact the food chain/food web under future acidified ocean conditions.
Yehia RS, Saleh AM, {Bani Ismail} M, Al-Quraishy S, Al-Amri O, Abdel-Gaber R.  2022.  {Isolation and characterization of anti-proliferative and anti-oxidative mannan from Saccharomyces cerevisiae}. Journal of King Saud University - Science. 34:101774. AbstractWebsite

Mannan oligosaccharide is one of the major components of the yeast cell wall. In the present study, the production, characterization, and bioactivity of yeast mannan were investigated. Four indigenous yeast isolates were obtained from various kinds of juice collected from local markets in Al-Ahsa, KSA, and analyzed using morphological and biochemical methods. Isolate RY1 showed the highest production of mannan. RY1 was identified as Saccharomyces cerevisiae based on morphological characteristics and sequencing of the 18S rRNA gene (GenBank accession number LC479088.1). Mannan-RY1 was characterized by polymer analytical methods, 13C and 1H nuclear magnetic resonance spectroscopy (NMR), and infrared spectroscopy (IR). Interestingly, the mannan extracted from RY1 showed a significant ability to scavenge hydroxyl radicals and superoxide anions. In addition, mannan was found to have pronounced anti-tumor activity against liver (HepG2) and breast cancer (MCF7) cell lines. The results presented in this study confirm the bio-therapeutic activity of S. cerevisiae mannan, which could be used as a potential drug for cancer treatment.
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