毛白杨长链非编码RNAs响应镉胁迫的遗传调控机制

Cadmium pollution not only affects plant growth and development, but also threatens human health. But so far, the regulatory mechanism of many genes expression under cadmium stress is still unclear. And as an important regulatory factor, lncRNAs play an important regulatory role in plant growth, development and stress physiology. Therefore, lncRNAs may be involved in the genetic regulatory network related to cadmium stress. Adopting bioinformatics technology, population genetics technology and molecular biology technology, our project would launch three research topics as follows: (1) Identification of differentially expressed lncRNAs under cadmium stress and prediction of their target genes in Populus tomentosa, and transcriptome analysis of differentially expressed target genes; (2) Analysis of the genetic effects of SNPs of differentially expressed lncRNAs and their target genes on phenotypes using the association analysis strategy combining with the population phenotypes associated with growth and photosynthesis, and exploration the significantly correlated genetic factors;(3) Analysis and validation of 2-3 significantly related and important lncRNAs and their target genes in the biological functions of P. tomentosa and Arabidopsis thaliana. Therefore, we believe that the study of this project in the natural population of P. tomentosa will provide important scientific theoretical basis and technical guidance for tree molecular breeding.

镉污染不仅影响植物的生长发育，而且威胁到人类的生命健康。但到目前为止，镉胁迫下许多基因表达调控机制还不是很清楚，而lncRNAs作为一类重要的调控因子在植物生长发育和逆境生理等方面起着重要的调控作用，因此，lncRNAs可能参与到镉胁迫相关的遗传调控网络中。本项目拟采用生物信息学技术、群体遗传学技术和分子生物学技术，拟开展：（1）毛白杨镉胁迫条件下差异表达的lncRNAs的发掘及其靶基因的预测，差异表达的靶基因的转录组分析；（2）结合生长和光合作用相关的群体表型，利用关联分析策略解析差异表达的lncRNAs及其靶基因内SNPs位点对表型的遗传效应，发掘显著关联的遗传因子；（3）2-3个显著关联的重要的lncRNAs及其靶基因在杨树和拟南芥中的生物功能的分析验证。申请者认为，在毛白杨自然群体中开展本项目的研究，将为林木分子育种提供重要的科学理论依据与技术指导。

镉作为重金属污染的主要元素之一，严重威胁了土壤生态系统和人类生命健康。与草本植物相比，多年生木本植物对镉具有更强的超积累能力和耐受能力，是吸附土壤镉的理想植物材料。然而，多年生林木响应镉胁迫的生理变化规律及转录调控模式尚不清晰；长链非编码RNA（long non-coding RNA，lncRNA）参与了植物的生长发育等调控过程，但多年生木本植物lncRNAs响应镉胁迫的遗传机制有待深入研究。为此，本研究以毛白杨为材料，发现在镉胁迫条件下，毛白杨的光合作用发生了显著变化。采用链特异性高通量测序技术，共鉴定了172个毛白杨镉胁迫响应差异表达lncRNAs，剖析了杨树响应镉胁迫的转录调控模式。依托毛白杨种质资源群体内435株个体，结合光合作用和生长相关性状，利用加性、显性与上位性效应的关联分析策略，进一步解析了lncRNAs及其靶基因内的等位变异对光合作用和生长相关性状的遗传效应，构建了镉胁迫响应关键lncRNA及其靶基因的上位性互作网络。最后，利用遗传转化技术，解析了阐明了镉胁迫响应关键lncRNA-mRNA模块 MSTRG.22608.1-PtoMYB73和MSTRG.5634.1-PtoMYB27增强杨树镉胁迫耐受性的作用机制，研究结果为林木抗逆性状遗传改良提供了理论指导与技术支撑。

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