Auxin-Glucose Conjugation Protects the Rice (Oryza sativa L.) Seedlings Against Hydroxyurea-Induced Phytotoxicity by Activating UDP-Glucosyltransferase Enzyme

Frontiers in Plant Science

卷:12

Nirmal Kumar Ramasamy¹  Keum-Ah Lee²  Hyeonji Choe³  Song Yeob Kim³  Vimalraj Kantharaj³  Hadjer Chohra³  Yong Bok Lee³  Young-Eun Yoon³  Vikranth Kumar⁴  Young-Nam Kim⁵  Mi Sun Cheong⁵ 

[1] Department of Biotechnology, PSGR Krishnammal College for Women, Coimbatore, India;

[2] Department of Smart Agro-Industry, Gyeongsang National University, Jinju, South Korea;

[3] Division of Applied Life Science (BK 21 Four), Gyeongsang National University, Jinju, South Korea;

[4] Division of Plant Sciences, University of Missouri, Columbia, MO, United States;

[5] Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea;

关键词: auxin;    auxin conjugate;    hydroxyurea (HU);    reactive oxygen species (ROS);    ribonucleotide reductase (RNR);    uridine 5′-diphosphate-glucosyltransferase (UGT);   

DOI  :  10.3389/fpls.2021.767044

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown