Antioxidant enzymatic activity is linked to waterlogging stress tolerance in citrus

ABSTRACT KDM5A and KDM5B histone-demethylases are overexpressed in many cancers and have been involved in drug tolerance. Here, we describe that KDM5A, together with KDM5B, contribute to replication stress (RS) response and tolerance. First, they positively regulate RRM2, the regulatory subunit of ribonucleotide reductase. Second, they are required for optimal levels of activated Chk1, a major player of the intra-S phase checkpoint that protects cells from RS. We also found that KDM5A is enriched at ongoing replication forks and associates with both PCNA and Chk1. Because RRM2 is a major determinant of replication stress tolerance, we developed cells resistant to HU, and show that KDM5A/B proteins are required for both RRM2 overexpression and tolerance to HU. Altogether, our results indicate that KDM5A/B are major players of RS management. They also show that drugs targeting the enzymatic activity of KDM5 proteins may not affect all cancer-related consequences of KDM5A/B overexpression.

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Influence of Ascorbic Acid, Gibberellic Acid and Moringa oleifera Extract for Alleviating Salinity Stress by Enhancing Antioxidant Enzymatic Activity and Some Physiological Studies on Two Tomato Cultivars

Journal of Applied Life Sciences International ◽

10.9734/jalsi/2020/v23i830180 ◽

2020 ◽

pp. 39-62

Author(s):

Ibtisam Mohammed Ali Alsudays ◽

Hameda El Sayed Ahmed El Sayed

Keyword(s):

Enzymatic Activity ◽

Salinity Stress ◽

Moringa Oleifera ◽

Mineral Nutrient ◽

Nutrient Elements ◽

Tomato Seeds ◽

Tomato Cultivars ◽

Inorganic Mineral ◽

Harmful Effects ◽

Antioxidant Enzymatic Activity

This study aimed to explain the influence of Ascorbic acid (ASA), Gibberellic Acid (GA3) and Moringa oleifera Leaf Extract (MLE) for alleviating salinity stress by enhancing antioxidant enzymatic activity as follow: Super Oxide Dismutase (SOD), Catalase (CAT), Ascorbate Peroxidase (APX), and Glutathione Reductase (GR); nitrogenous components (proline and total amino acids) and some inorganic mineral nutrient elements in two tomato cultivars, cv. Cobra (resistant) and cv. Newton (sensitive) under salinity stress. Germination tomato seeds after soaking in ASA (0.75 mM); GA3 (0.05 mM) and MLE (5%), transplanted to plastic containers containing a mixture of sand/peat-moss (1:2). The tomato seeds for both cultivars watering using distilled water until the true leaf appearance then irrigated with NaCl salinity concentrations (0.0, 50, 100, 150, 200 mM) alternative with Hoagland nutrient solution. The experiment was carried out under greenhouse conditions with temperature 18oC±1oC (night) & 22oC±2°C (day) and relative humidity varied between 60 - 70%. Overall, the results indicated that the organic and inorganic components in tomato plants for both cultivars increased significantly in the present of ASA, GA3 and MLE under salinity stress respectively compared with control, there by reduces the harmful effects of salinity and increases resistance to salinity stress more than in the absent of ASA, GA3 and MLE. The data provide strong support to the hypothesis that exogenous application of ASA, GA3 and MLE reduced the harmful effects of NaCl concentrations and increases resistance to salinity in cv. Cobra and cv. Newton respectively. The evident recorded a significantly increased the antioxidant enzymes activity, proline, total amino acids and inorganic macro-mineral nutrient elements (N+3, P+3, K+, Ca+2 & Mg+2) and micro-nutrient mineral elements (Mn+2, Fe+3 & B+2) but after soaked the seeds in ASA, GA3 and MLE, these components tended to increase more compared with the control. Whereas, the tomato seeds soaked before planting in ASA, GA3 and MLE which leads to remarkably increasing more for all antioxidant enzymatic activity, nitrogenous components and inorganic mineral nutrient elements contents respectively. The relationship between compatible solutes (osmolytes) here are the strategies that plants have developed to tolerate salt stress and produced new strains adapted to salinity stress.

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