全寄生肉苁蓉属物种与宿主植物之间水平转移基因和microRNA的微进化机制

Horizontal gene transfer (HGT) between parasitic plants and their hosts has been one of hotspots of evolutionary biology. It can provide the new evidence on a large evolutionary time-scale for resolution of the core issue how transgenes evolve in natural condition, which remains largely unknown. Despite relatively high rate of horizontal transfer of transcripts in holoparasitic plants, it is lacking of micro-evolution mechanism for understanding unclear how many horizontally transferred entire encoding genes lay on the foundation of parasitism, which genes help parasitic plants to adapt different hosts and how do they evolve. In the present study, we select the representative system of holoparasitic taxa, the species of Cistanche, and their hosts to analyze the difference in the number, type, occurrence and variation patterns of the encoding genes undergone the horizontal transfer and the genes by employing approaches of gene cloning, RT-PCR, RNA-Seq, expression profiling and small-RNA-seq. Based on the data from multiple omics, the general characteristics, classification, functional differences and selection force of the horizontally transferred genes and microRNAs between host and parasitic plant will be uncovered. Finally, the basal laws of micro-evolution mechanism for the interaction between these transgenes and other genes and their effects on the adaptive evolution of parasitic plants will be concluded and summarized based on all of the evidence available.

寄生植物与宿主之间水平基因转移，能为理解自然条件下转基因是如何进化的，提供新的大时间尺度的进化证据，已成为进化生物学的热点研究领域。尽管已有研究表明全寄生植物有相对较高的转录本水平转移，但迄今为止，究竟发生水平转移的共有完整编码基因如何奠定了寄生习性的基础、哪些基因帮助寄生植物实现与不同宿主的相互适应以及它们是如何进化的，一直缺乏进化机制方面的深入了解。在已有研究基础上，本研究以典型的全寄生肉苁蓉属植物与其不同宿主作为对象，通过转录组、表达谱、小RNA测序等方法，结合系统发育基因组学分析，检测宿主-寄生植物间发生水平转移的编码基因和microRNA在数量、类别、发生方式和变异式样的差别。从多组学水平揭示它们的共同特征、归类、功能差异和选择驱动力，结合已获得的研究结果，系统地探讨受到选择的这些外源基因与其它基因相互作用微进化机制的基本法则、解析它们对寄生植物适应性进化的影响。