Serine hydroxymethyltransferase localised in the endoplasmic reticulum plays a role in scavenging H2O2to enhance rice chilling tolerance

Background Rice is a chilling-sensitive crop that would suffer serious damage from low temperatures. Overexpression of theLsi1gene (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. Results A higher transcription level ofOsSHMTwas detected inLsi1-OX rice than in the wild type. Histone H1 and nucleic acid binding protein were found to bind to the promoter region ofOsSHMTand regulate its expression, and the transcription levels of these proteins were also up-regulated in theLsi1-OX rice. Moreover, OsSHMT interacts with ATP synthase subunit alpha, heat shock protein Hsp70, mitochondrial substrate carrier family protein, ascorbate peroxidase 1 and ATP synthase subunit beta.Lsi1-encoded protein OsNIP2;1 also interacts with ATP synthase subunit beta, and the coordination of these proteins appears to function in reducing reactive oxygen species, as the H(2)O(2)content of transgenicOsSHMT Arabidopsis thalianawas lower than that of the non-transgenic line under chilling treatment. Conclusions Our results indicate that ER-localised OsSHMT plays a role in scavenging H(2)O(2)to enhance the chilling tolerance ofLsi1-OX rice and that ATP synthase subunit beta is an intermediate junction between OsNIP2;1 and OsSHMT.