Serine hydroxymethyltransferase localised in the endoplasmic reticulum plays a role in scavenging H2O2 to enhance rice chilling tolerance

Luke Yang,Zhong Li,Xue Yan,Wenxiong Lin,Lanlan Li,Pengli Zhang,Dan Mu,Changxun Fang

doi:10.1186/s12870-020-02446-9

Abstract

BackgroundRice is a chilling-sensitive crop that would suffer serious damage from low temperatures. Overexpression of the Lsi1 gene (Lsi1-OX) in rice enhances its chilling tolerance. This study revealed that a serine hydroxymethyltransferase (OsSHMT) mainly localised in the endoplasmic reticulum (ER) is involved in increasing tolerance to chilling.ResultsA higher transcription level of OsSHMT was detected in Lsi1-OX rice than in the wild type. Histone H1 and nucleic acid binding protein were found to bind to the promoter region of OsSHMT and regulate its expression, and the transcription levels of these proteins were also up-regulated in the Lsi1-OX rice. Moreover, OsSHMT interacts with ATP synthase subunit α, heat shock protein Hsp70, mitochondrial substrate carrier family protein, ascorbate peroxidase 1 and ATP synthase subunit β. Lsi1-encoded protein OsNIP2;1 also interacts with ATP synthase subunit β, and the coordination of these proteins appears to function in reducing reactive oxygen species, as the H2O2 content of transgenic OsSHMT Arabidopsis thaliana was lower than that of the non-transgenic line under chilling treatment.ConclusionsOur results indicate that ER-localised OsSHMT plays a role in scavenging H2O2 to enhance the chilling tolerance of Lsi1-OX rice and that ATP synthase subunit β is an intermediate junction between OsNIP2;1 and OsSHMT.

Highlights

Rice is a chilling-sensitive crop that would suffer serious damage from low temperatures
Scanning electron microscope (SEM) images of the leaves revealed that silica bodies in the Low silicon gene 1 (Lsi1)-OX rice leaves were bigger than those of the Dular rice (Fig. 1c)
Subcellular localisation of OsSHMT (LOC_Os03g52840) in the rice protoplast showed that yellow fluorescence was concentrated around the nucleus, and no obvious endonuclear fluorescence was observed, whereas significant yellow fluorescence was seen in the whole nucleus in the rice protoplast transformed with the eYFP vector (Fig. S1)

Summary

Introduction

Rice is a chilling-sensitive crop that would suffer serious damage from low temperatures. Fang et al [6] documented that chilling treatment inhibited the expression of chlorophyll synthesis genes and promoted the expression of proteasome genes from temperature-sensitive Dular rice When the silicon-absorbing gene (Lsi1) was overexpressed in Dular rice, the chilling tolerance of the transgenic line was significantly improved, and the leaves maintained their fresh green colour under chilling treatment. The expression of genes from the photosynthesis pathway of transgenic rice was enhanced under low temperature stress, and the expression of genes involved in the proteasome was down regulated. The transcription level of the gene encoding serine hydroxymethyltransferase (SHMT, LOC_Os03g52840) was upregulated in the transgenic rice, but down-regulated in the wild-type, and the expression of its corresponding miRNA changed in an opposite way, indicating that OsSHMT may be involved in regulating the chillingtolerance of Dular [6]

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Discussion

Conclusion