长链非编码RNA SILR编码的小肽SILR-Pep介导的桑树耐盐分子机制研究

土壤高盐是限制农林业生产的重要环境因素。研究表明有些lncRNA编码的小肽在植物生长发育和胁迫响应中具有重要作用，但有关lncRNA编码小肽参与植物盐胁迫响应的研究还鲜有报道。SILR是我们在桑树中发现的一种新的盐诱导lncRNA，试验证明其能编码一种小肽SILR-Pep，在根中过表达SILR或叶面喷施SILR-Pep均能显著增强桑树耐盐性，而过表达sORF突变的SILR，转基因桑树的耐盐性没有明显改变。因此，我们推测SILR-Pep可能是一种新的耐盐调控因子。本项目拟进一步明确SILR-Pep的耐盐性能，探明其表达特性及在桑树中是否具有长距离运输特性，鉴定SILR-Pep的互作蛋白质并探究其对SILR-Pep耐盐性能的影响，解析SILR-Pep调控的基因网络和参与的信号转导途径，阐明SILR-Pep介导的桑树耐盐机制。研究结果对于桑树耐盐品种培育和深入解析植物耐盐分子机制具有重要意义。

High soil salinity is one of the major abiotic stresses that limit plant growth and has a strong influence on the development of agriculture and forestry. Recent researches showed that some lncRNA-encoded peptides have diverse functions in both plant development and stress responses. To date, however, there have been few reports of lncRNA-encoded peptides associated with salinity stress tolerance. A novel lncRNA designated as SILR was identified and found to be up-regulated in response to salt stress in mulberry, and our results showed that the transgenic mulberry plants overexpressing SILR in the roots are much more tolerant to salt stress than wild type mulberry plants. Interestingly, it was demonstrated that SILR contains a short open reading frame (sORF) which can be translated into a small peptide (named as SILR-Pep) and exogenous application of synthetic SILR-Pep peptide was capable of enhancing salinity tolerance of plants. However, when the start codon of the sORF was mutated and the mutant SILR gene was overexpressed in the mulberry, there were no significant differences in the salt tolerance between the transgenic and wild type mulberry plants. Therefore, we ascertained the potential functional contribution of SILR-Pep to salt tolerance and speculated that it might be a novel regulator of salt tolerance in mulberry. In this study, the functions of SILR-Pep in response to salt stress in mulberry will be further defined. Meanwhile, the expression characteristics of SILR-Pep and whether it has long-distance transportation characteristics in mulberry will be explored. In addition, the interaction proteins of SILR-Pep will be identified and their roles in salt tolerance associated with SILR-Pep will be explored. Moreover, the genome-wide gene regulatory networks controlled by SILR-Pep and the roles of SILR-Pep in the signal transduction pathway involved in the response to salt stress will be dissected. Based on these results, the salt tolerance molecular mechanisms mediated by SILR-Pep in mulberry will be elucidated. The information obtained in this study will be of great significance for cultivation of new mulberry varieties with salt tolerance and further understanding the molecular mechanism of salt tolerance in plants.