The 2'-O-methyladenosine nucleoside modification gene OsTRM13 positively regulates salt stress tolerance in rice.

Youmei Wang,Zhen Hu,Dongqin Li,Staffan Persson,Peng Chen,Junbao Gao,Rui Zhang,Xiaohuan Jin,Bo Zheng,Xukai Li

doi:10.1093/jxb/erx061

Abstract

Stress induces changes of modified nucleosides in tRNA, and these changes can influence codon-anticodon interaction and therefore the translation of target proteins. Certain nucleoside modification genes are associated with regulation of stress tolerance and immune response in plants. In this study, we found a dramatic increase of 2'-O-methyladenosine (Am) nucleoside in rice seedlings subjected to salt stress and abscisic acid (ABA) treatment. We identified LOC_Os03g61750 (OsTRM13) as a rice candidate methyltransferase for the Am modification. OsTRM13 transcript levels increased significantly upon salt stress and ABA treatment, and the OsTrm13 protein was found to be located primarily to the nucleus. More importantly, OsTRM13 overexpression plants displayed improved salt stress tolerance, and vice versa, OsTRM13 RNA interference (RNAi) plants showed reduced tolerance. Furthermore, OsTRM13 complemented a yeast trm13Δ mutant, deficient in Am synthesis, and the purified OsTrm13 protein catalysed Am nucleoside formation on tRNA-Gly-GCC in vitro. Our results show that OsTRM13, encoding a rice tRNA nucleoside methyltransferase, is an important regulator of salt stress tolerance in rice.

Highlights

Modified nucleosides are derivatives of the four common nucleosides, adenosine (A), guanosine (G), uridine (U), and cytidine (C)
Salt stress and abscisic acid (ABA) treatment induced a significant increase in 2′-O-methyladenosine nucleosides in rice
We report that salt and ABA treatments induced Am nucleoside levels, and that OsTRM13 is involved in Am nucleoside formation in rice

Summary

Introduction

Modified nucleosides are derivatives of the four common nucleosides, adenosine (A), guanosine (G), uridine (U), and cytidine (C). They are important for transfer RNA (tRNA), since more than 85% of all modified nucleosides are present on tRNA molecules (RNA modification database, http://rna-mdb.cas.albany.edu/; Cantara et al, 2011). The modified nucleosides in tRNAs can change in response to alterations of environmental conditions, and across developmental stages, including aging, starvation, and different stress conditions (Dirheimer et al, 1995; Suzuki and Nagao, 2011b; Dedon and Begley, 2014). It has been suggested to work as a ‘sensing system’ to link environmental and developmental stimuli to cellular translational machinery and metabolism (Chan et al, 2012; El Yacoubi et al, 2012; Zinshteyn and Gilbert, 2013)

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