肉苁蓉寄生信号物质及其调控分子机制研究

Cistanche plants are well-known root parasitic species. To reveal the parasitic signal substance and their regulation mechanisms of Cistanche plants, we select Cistanche tubulosa and C. deserticola which are authenticated as the two original species of Cistanches Herba in Chinese Pharmacopoeia as representative cases to clarify the underlying mechanisms of the parasitism. Firstly, serial techniques, including the laboratory cultivation of their hosts, Tamarix plants and Haloxylon ammodendron, and the collection, detection, isolation, and identification of their hosts root secreta will be developed; Secondly, the seed germination rate acts as the indicator to develop the optimal germination conditions for Cistanche seed as well as to search the ideal assay method; Thirdly, chemical purification and identification of those root secreta will be jointly guided by some sensitive detective technologies, e.g. GC-MS and LC-MS, and seed germination assays to obtain those substances being responsible for inducing the germination of Cistanche seeds and governing the parasitism of C. tubulosa and C. deserticola; Finally, those effective substances will be applied to search the genes participating in the regulation pathways of seed germination using transcriptome sequencing, real-time PCR, Western-Blot, etc. and to find their targets along with the related signal pathways for seed germination via the construction of the yeast two-hybrid system and the development of tandem affinity purification method. In brief, this study aims to clarify the parasitic signal substance and the related regulation pathways regarding the parasitism of Cistanche plants. The findings expected to be beneficial for clarifying the secrets for the parasitism mechanism of parasitic plants, and improving significantly the germination as well as inoculation rates of Cistanche seeds, indicating that this study is of great importance in terms of academic value and application prospect.

针对根寄生植物肉苁蓉属植物寄生信号物质及其调控机制的科学问题，以中国药典收载的管花肉苁蓉和荒漠肉苁蓉为研究对象，建立其寄主柽柳和梭梭培养、根系分泌物收集、分离、鉴定技术体系；以萌发率为指标，建立肉苁蓉种子萌发适宜条件和萌发率测定方法；以LC-MS等高灵敏检测手段为导向，结合种子萌发率筛选，分离鉴定诱导肉苁蓉种子萌发的寄主根分泌物，阐明管花肉苁蓉和荒漠肉苁蓉寄生信号物质。利用转录组测序、Real-TimePCR 和Western Blot 等方法确定寄生信号物质诱导肉苁蓉种子萌发关键调控基因，通过酵母双杂、串联亲和纯化等方法寻找互作蛋白，确定调控种子萌发信号通路，初步阐明寄生信号物质诱导肉苁蓉种子萌发分子机制。本研究系统阐明肉苁蓉寄生信号物质及其调控机制，揭示寄生植物神奇的寄生奥秘，为全面提升肉苁蓉种子萌发率和接种率、实现精准接种奠定基础，具有重要学术价值和应用前景。

针对根寄生植物肉苁蓉属植物寄生信号物质及其调控机制的科学问题，本项目在发现荒漠肉苁蓉新寄主四翅滨藜的基础上，通过寄主不同培养体系分泌寄生信号物质试验，发现只有雾培方式寄主植物根系才能产生寄生信号物质；应用高分辨气质联用仪鉴定肉苁蓉种子萌发的信号物质是一类十个碳左右的烷烃或者烯烃类物质，发现干旱胁迫是寄主植物根系分泌信号物质的必要条件；通过转录组测序和蛋白“钩钓”策略发现了参与调控肉苁蓉种子萌发的五个关键基因，初步阐明调控肉苁蓉种子萌发的主要信号通路为14-3-3/ABI5。研究过程中，发现寄主植物根尖或者丝状根是产生寄生信号物质的具体部位，丝状根或者根毛对寄生植物种子的粘附力是寄生植物定位的根本原因。本研究揭示了长期困扰寄生植物学界的几个科学问题：1）寄主植物分泌寄生信号的确切部位；2）寄主植物分泌寄生信号物质的真正原因；3）寄生植物定位机制。上述问题的揭示和深入研究，对危害农作物的根寄生植物的防治和有益根寄生植物产量的提高，将会取得突破性进展，具有重要的应用价值。