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Reactive oxygen species (ROS) and reactive nitrogen species (RNS) incessantly produced as by-products of metabolism play significant roles in seed physiology. ROS (hydroxyl, superoxide radical and hydrogen peroxide) and RNS (nitric oxide, nitric dioxide, nitrous acid and dinitrogen tetroxide) content changes in all phases of seed life cycle that influence seed germination, dormancy and longevity. Recent studies illustrate that ROS and RNS are performing oxidative and nitrosative signaling to induce seed germination within oxidative window level. Besides, ROS/RNS-mediated post-translational modifications (PTM) like carbonylation, S-nitrosylation and nitration are gaining interest in promoting seed germination. Understanding the signalling pathways, cross-talk with plant hormones and their role in promoting seed germination and dormancy alleviation could pave way for hormone engineering that help in crop productivity, particularly under climatic changing conditions. In addition, role of antioxidants and glutathione thiols in protecting from oxidative damage indicate that these compounds can be used for seed viability/quality markers that aid in monitoring of crop establishment. In this review, sources of ROS and RNS, their cross-talk with plant hormones (prospects for hormone engineering), signalling functions pertaining to seed germination, dormancy and deterioration have been illustrated. In addition, seed quality markers under climatic changing conditions for effective monitoring of crop stand establishment and diagnostics development have been elucidated.

An easy and efficient large-scale synthesis of 1, 2,-di-O-acetyl-5-O-benzoyl-3-O-methyl-d-ribofuranose (8) was accomplished from commercial 1,2:5,6-di-O-isopropylidene-α-d-allofuranose in 7-steps and 30 % overall yield. The utility of protected 8 was demonstrated via synthesis of 9-(3'-O-methyl-β-d-ribofuranosyl)-6-chloropurine (21) and six other nucleoside analogues in good yields. A library of five novel base modified nucleosides were generated starting from purine nucleoside 21 via functional group manipulations. The 3'-O-modified nucleosides are known to act as chain terminator exerting antiviral activity. The synthesis strategy described herein offers direct access to 3'-O-alkylated nucleosides with wide range of applications, including cap analogues for mRNA vaccine production. This protocol provides a route to exclusive synthesis of 3'-O-alkylated nucleosides, devoid of isomeric 2'-O-alkylated products essential for both therapeutic and biological research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)