Objective Long non-coding RNA (lncRNA) is longer than 200 nt and generally does not code proteins. To explore the effect of lncRNA on the expression of neighbouring SAUR genes under low temperature, and provide a theoretical basis for studying the ability of rice seeds to germinate at low temperature.

Method lncRNA SVR was investigated in response to cold stress in previous research of National Engineering Research Center of Plant Space Breeding, South China Agricultural University. The secondary structure of lncRNA SVR was analysed by bioinformatics, and the cold stress motifs within lncRNA SVR was searched. The expression characteristics of lncRNA SVR and SAUR genes were analysed by qRT-PCR.

Result In this study, highly similar cold stress response motifs were found in the sequence of lncRNA SVR and at the stem-loop junction. Expression characterization showed that cold stress during seed germination continuously decreased the expression of lncRNA SVR, and the expression of some neighbouring SAUR genes was significantly higher under cold stress than that at room temperature, indicating that the neighbouring SAUR genes could respond to cold stress to some extent as well as lncRNA SVR. Expression correlation analysis showed that the expression relationship between lncRNA SVR and these SAUR genes in low temperature germination were all negatively correlated, and the expression of lncRNA SVR and OsSAUR55 showed a significant negative correlation. Further analysis of SAUR gene expression in low temperature seed germination in the lncRNA SVR knockout lines showed that the decrease of lncRNA SVR in the knockout lines was lower than that in the wild type, and the increase in expression of OsSAUR41, OsSAUR53, OsSAUR54 and OsSAUR55 was significantly lower than that in the wild type.

Conclusion lncRNA SVR is able to negatively regulate the expression of OsSAUR55, further respond to low temperature stress.