杨柳树上栅锈菌个体发育的适应性演化

Many species of Melampsora on poplar were found no alternate host, or without alternate host at all, and absence of Telia in the life cycle, whereas, somatic hybridizations among inter- and intra- species occurred frequently, causing genetic variation happened easily under the stress of host selecting and harsh environment. Due to reasons above, life cycle of species in Melampsora displayed highly diverse, and the limitation of taxonomy for some species is still uncertain. This project is doomed to extensively collect samples of Melampsora rust of poplars under different environmental factors and hosts, and doomed to clarify the nuclear evolutionary of ontogenic life cycle by fluorescent dying and transmission electron microscopic technologies after Melampsora fungi being sampled, artificial inoculation and overwinter telia induction. Mating-related genes including STE3 pheromone receptors, karyogamy genes, eukaryotic meiotic genes were implemented for real time quantitative PCR expression, and monoclonal antibody proteins both of mating-related genes and karyogamy genes were employed for subcellular molecular-location research, these processes are destined to uncover the important molecular events during nuclear evolutionary in the life cycle of those important poplar rust species. Combined molecular phylogenic results with those cytological ontogeny and molecular biology of nuclear-regulated gene, this project will clear the evolutionary relationship among adaptive species in Melampsora on poplars, and this will hammer the theoretic basis for further understanding the epidemiologic mechanisms of poplar rust diseases.

杨树上栅锈菌由于有的种很难发现或没有转主寄主、一些锈菌种生活史缺少冬孢子阶段、种间杂交频繁、在环境和寄主选择压下遗传易变性等原因，栅锈菌生活史表现出复杂的多样性，一些种的分类学地位也长期受到争议。本研究将系统收集不同生境中杨树上栅锈菌种，通过对自然生长、人工接种及人工诱导冬孢子形成和萌发，借助细胞核荧光染色和叶肉组织电镜技术，研究栅锈菌个体发育中细胞核事件；根据交配位点基因、细胞核融合基因、细胞核分裂基因的RT-qPCR定量表达分析，研究核亲和基因 、交配位点基因单克隆抗体的亚细胞定位，进一步揭示杨树上重要栅锈菌种细胞核演化过程中的分子事件；综合分子系统学研究结果，从而廓清杨树上栅锈菌种间演化关系及生态适应性特点，为深入研究杨树锈病流行机制奠定理论基础。

我国是杨树天然分布和引种造林大国，杨树锈病是威胁杨树人工林产业的一种广谱、流行性病害，具有种类多、种群复杂、适应性强等特点。本项目对杨树锈病主要栅锈菌流行种的系统进化、生活史循环和环境适应性等内容进行了研究。发现新记录种北美栅锈菌和松杨栅锈菌多核体菌株；证明了超低温贮藏中MAKP介导的过氧化作用对微管蛋白的影响及细胞核分裂基因的异常表达是多核体产生的原因，多核体菌系的致病性和环境适应能力较双核体菌系高；主要流行种交配型基因、细胞核融合基因的系统学关系在长史型锈菌与半史型锈菌差异明显，北美栅锈菌与松杨栅锈菌的交配型基因系统进化关系紧密、种间容易亲和，而细胞核融合基因Kar5、Kar9、STE3等的表达，北美栅锈菌较松杨栅锈菌均更早；半史型锈菌（马格栅锈菌、粉被栅锈菌）交配基因、细胞核分裂相关基因均与长史型锈菌系统进化关系远，生活史内生菌特点突出；寄主选择压力及非寄主抗性对松杨栅锈菌种群均具有明显的影响，秦岭林区很可能是松杨栅锈菌遗传中心，叶片角质层成份、下表皮细胞壁厚度在杨树抗锈性中具有重要作用。发表相关论文8篇，培养研究生6名，申请专利1项。研究结果对指导杨树锈病的检验检疫、防控管理和抗病育种具有指导意义。