Please use this identifier to cite or link to this item: http://localhost:8080/xmlui/handle/123456789/5131
Title: AUXIN-GLUCOSE CONJUGATION PROTECTS THE RICE (ORYZA SATIVA L.) SEEDLINGS AGAINST HYDROXYUREA-INDUCED PHYTOTOXICITY BY ACTIVATING UDP-GLUCOSYLTRANSFERASE ENZYME
Authors: Vimalraj, Kantharaj
Nirmal Kumar, Ramasamy
Young-Eun, Yoon
Mi Sun, Cheong
Young-Nam, Kim
Keum-Ah, Lee
Vikranth, Kumar
Hyeonji, Choe
Song, Yeob Kim
Hadjer, Chohra
Yong, Bok Lee
Keywords: auxin
auxin conjugate
hydroxyurea (HU)
reactive oxygen species (ROS)
ribonucleotide reductase (RNR)
uridine 5′-diphosphate-glucosyltransferase (UGT)
Issue Date: Feb-2022
Publisher: Frontiers in Plant Science
Abstract: Hydroxyurea (HU) is the replication stress known to carry out cell cycle arrest by inhibiting ribonucleotide reductase (RNR) enzyme upon generating excess hydrogen peroxide (H2O2) in plants. Phytohormones undergo synergistic and antagonistic interactions with reactive oxygen species (ROS) and redox signaling to protect plants against biotic and abiotic stress. Therefore, in this study, we investigated the protective role of Indole-3-acetic acid (IAA) in mitigating HU-induced toxicity in rice seedlings. The results showed that IAA augmentation improved the growth of the seedlings and biomass production by maintaining photosynthesis metabolism under HU stress. This was associated with reduced H2O2 and malondialdehyde (MDA) contents and improved antioxidant enzyme [superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD)] activity that was significantly affected under HU stress. Furthermore, we showed that the HU stress-induced DNA damage leads to the activation of uridine 5'-diphosphate-glucosyltransferase (UGT), which mediates auxin homeostasis by catalyzing IAA-glucose conjugation in rice. This IAA-glucose conjugation upregulates the RNR, transcription factor 2 (E2F2), cyclin-dependent kinase (CDK), and cyclin (CYC) genes that are vital for DNA replication and cell division. As a result, perturbed IAA homeostasis significantly enhanced the key phytohormones, such as abscisic acid (ABA), salicylic acid (SA), cytokinin (CTK), and gibberellic acid (GA), that alter plant architecture by improving growth and development. Collectively, our results contribute to a better understanding of the physiological and molecular mechanisms underpinning improved growth following the HU + IAA combination, activated by phytohormone and ROS crosstalk upon hormone conjugation via UGT.
URI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8888425/pdf/fpls-12-767044.pdf
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