丛枝菌根真菌和深色有隔内生真菌协同提高灰杨耐砷机理研究

Mechanisms of mycorrhizal fungi to improve the tolerance of heavy metals in forest trees have become one of the highlights of mycorrhiza field in recent years, especially, in the field of heavy metal pollution remediation and reconstruction. The application of mycorrhizal technology is also an important measure for ecological environment protection and sustainable development. This project is based on the previous study on arbuscular mycorrhizal fungi (AMF) and black septum fungi (DSE) on the improvement of the physiological growth of poplar under arsenic stress. We observe the damage of cell ultrastructure of poplar by using transmission electron microscopy. The effects of the both fungi on chelation, absorption and distribution for arsenic ion in the root of poplar are analyzed by using Non-invasive micro-test and atomic absorption technology. The expression difference of arsenic resistance related function and regulation gene in poplar are analyzed, the structural features of the arsenic resistant gene encoding protein are predicted, and its biological function is explored by using the technology of Solexa high throughput transcriptome sequencing, bioinformatics, and prokaryotic expression. The mechanisms of AMF and DSE to repair, filter, transport and stabilize arsenic in poplar will reveal, and the molecular mechanisms of its regulation of the expression of arsenic tolerant gene in poplar will also elucidate. Finally, the mechanisms of AMF and DSE improving the arsenic resistance of poplar will illustrate. The research has important theoretical and practical significance on the application of mycorrhiza technology to improve the heavy metal resistance of trees.

对菌根真菌提高林木耐重金属机理的探讨，已成为近年来菌根领域研究的重点之一，在土壤重金属污染修复重建中倍受关注，菌根技术的应用成为生态环境保护与可持续发展的重要举措之一。本项目在课题组前期探索砷胁迫下丛枝菌根真菌（AMF）和黑色有隔内生真菌（DSE）提高灰杨生理生长基础上，利用透射电镜观察AMF和DSE缓解灰杨亚细胞超微结构的损伤情况；通过非损伤微测和原子吸收技术，分析AMF和DSE改善砷在灰杨体内螯合、吸收、转运和分布的情况；利用Solexa高通量转录组测序、生物信息学和原核表达技术，筛选AMF和DSE调控显著的灰杨耐砷基因，预测耐砷基因编码蛋白的结构特征并探究生物学功能。从而揭示AMF和DSE对灰杨体内砷修复、过滤、转运和稳定的解毒机理，以及其调控灰杨耐砷基因表达的分子机理，最终阐明AMF和DSE提高灰杨耐砷的细胞和分子机理，该研究对应用菌根技术提高林木耐重金属性具有重要的理论与实践意义

对菌根真菌提高林木耐重金属机理的探讨，已成为近年来菌根领域研究的重点之一。本项目主要探讨丛枝菌根真菌（AMF）和黑色有隔内生真菌（DSE）提高灰杨耐砷机理，取得的研究结果如下：砷胁迫条件下双接种AMF和DSE，（1）提高了灰杨生理生长指标、光合特性和叶绿素荧光参数、抗氧化酶活性以及活性氧代谢物质含量；（2）降低As对灰杨叶绿体、线粒体等超微结构的损伤，并使As在灰杨叶肉细胞内电子致密颗粒聚集性更强；（3）加强了灰杨树根系对As的固定、降低了As向地上部的转移，影响了其在灰杨树叶肉细胞内的迁移和聚集，由此降低了As对灰杨的毒害作用；（4）通过转录组学KEGG功能富集方法对砷胁迫下AMF和DSE共诱导灰杨差异表达基因进行分析，发现砷胁迫下AMF和DSE共诱导产生的DEGs参与的通路有57条，其中有13条通路显著性富集（p<0.05），主要集中在膜的转运途径（3个）、萜类和聚酮类物质代谢途径（4个）和碳水化合物代谢途径（4个）和氨基酸代谢途径（6个）等，这些通路这可能是AMF和DSE共诱导灰杨根系响应砷胁迫的代谢和转导途径；（5）通过RT-PCR，验证了As胁迫下双接种AMF和DSE，显著调控了灰杨两种 H+-ATPases 相关的基因和7种与重金属转运相关的基因的表达。本研究最终阐明AMF和DSE提高灰杨耐砷的细胞和分子机理，该研究对应用菌根技术提高林木耐重金属性具有重要的理论与实践意义。