Salt stress tolerance analysis of SAIR6 long non-coding RNA in Tamarix hispida

  Objective  Long non-coding RNA (lncRNA) is a class of transcripts, which are larger than 200 nt in length and have extremely low protein-coding ability or without protein-coding ability. LncRNA is one of the key regulators of plant stress response. In this study, we studied the salt-tolerant physiological indexes under the salt stress of transiently overexpressing lncRNA of Tamarix hispida, and analyzed whether it had the ability to improve the salt tolerance and enrich the molecular mechanism of woody plant lncRNA in response to stress. It laid a foundation for the molecular regulation mechanism of lncRNA in T. hispida in response to salt stress.

  Method  In this study, a differential expression lncRNA-224223.1 was selected and named ThSAIR6 from transcriptomes of T. hispida under salt stress. The quantitative real-time PCR (qRT-PCR) was used to analyze the expression pattern of ThSAIR6 in leaf tissues of wild type T. hispida under salt stress. It could initially identify whether it responded to salt stress or not. Overexpression vectors (pROKII-ThSAIR6) were constructed in order to further study the stress tolerance. Overexpression (OE) and control T. hispida plants were obtained by agrobacterium-mediated high-efficient transient transformation system. Physiologic indexes related to salt tolerance of OE and control T. hispida plants under salt stress were measured in order to judge whether it could improve the salt tolerance of T. hispida plants.

  Result  The results of qRT-PCR showed that the expression quantity of ThSAIR6 in wild type plants significantly increased after salt stress for 24 h (P < 0.05), indicating that it could response to salt stress. The results showed that overexpression of ThSAIR6 in T. hispida plants significantly decreased the contents of H₂O₂ and \rmO_\rm2^ - \text• (P < 0.05), enhanced the POD and SOD activities (P < 0.05), and lowered the amount of dead cells, the electrolyte leakage and water loss rate of T. hispida tissues at the same time.

  Conclusion  In conclusion, lncRNA ThSAIR6 of T. hispida can response to salt stress. Overexpression of ThSAIR6 in plants significantly decreases the contents of H₂O₂ and \rmO_\rm2^ - \text• , enhances the POD and SOD activities, improves ROS scavenging, and reduces cell damage of plant tissues under salt stress, thus effectively improves its salt tolerance.