异源柳树嫁接的RNA转移及效应机制研究

Grafting could improve the plant yield，quality and resistance to environmental stress，which was also widely used in variety preservation and rapid propagation. Currently, most related reports are focusing on physiological and morphological changes of graft, further on analysis of the differential expressed genes. But the molecular mechanisms underlying differences in gene expression are not yet conclusive. Recently, we finished a whole genome sequencing of a salt sensitive variety of Salix.matsudana. The project here supposed to conduct the grafting research with the Salix.matsudana as scion and a salt tolerance variety of 9901 as rootstock. Via transcriptome analysis, the differential expressed mRNA and miRNA in scions would be identified and used for the construction of the gene network of grafting effect of willow. And based on the genome sequence information, the origin of the differential expressed genes would be determined, possibly from the rootstock through long distance transfer process. Further qualitative and quantitative analysis of the horizontal transfer genes would be conducted. All of the efforts will be valuable for the improvement of the theory system, and lay the foundation for more extensive application of grafting.

嫁接可以提高植物的产量、品质和抗逆性，也广泛应用于植物的良种保存和快速繁育。目前相关的报道主要集中于嫁接体生理、形态的改变以及基因表达差异的分析等，对导致基因表达差异的分子机制研究较为缺乏。在前期工作中，本课题组对一个敏盐的旱柳品种进行了基因组测序。本研究拟以此品种为接穗，嫁接至耐盐柳树9901砧木上。通过转录组测序，系统鉴定柳树嫁接体中mRNA及miRNA的表达差异，建立柳树嫁接效应的基因网络；借助基因组信息，分析转录组中差异表达基因的起源，鉴定嫁接过程中长距离转移的mRNA和miRNA，并进行转移RNA的定性定量分析，揭示嫁接的分子机制，完善嫁接的理论体系，为嫁接技术更广泛的应用奠定基础。

本研究建立了抗盐旱柳品种9901和敏盐旱柳品种沿江的同源和异源嫁接体系；通过生理指标测定，确定嫁接可以显著影响柳树的生长及抗盐性；通过转录组测序，系统鉴定了柳树嫁接体中mRNA及miRNA的表达差异，阐明了嫁接引起性状变异的分子基础；通过分子及生物信息学分析，鉴定了嫁接过程中存在的mRNA和miRNA长距离转移，揭示了嫁接引起性状变异的的分子机制。总之，本研究完善了嫁接的理论体系，为嫁接技术更广泛的应用奠定了重要基础；同时，基于本项目的研究，通过嫁接技术综合利用不同品种的优势，优化盐碱地治理的品种结构，促进社会生态文明建设。