small RNAs sequences from grafted Arabidopsis thaliana and Nicotiana benthamiana tissues. small RNAs sequences from grafted Arabidopsis thaliana and Nicotiana benthamiana tissues

A silencing signal in plants with an RNA specificity determinant moves through plasmodesmata and the phloem. To identify the mobile RNA we grafted Arabidopsis thaliana shoots to roots that would be a recipient for the silencing signal. Using high throughput sequencing as a sensitive detection method and mutants to block small RNA (sRNA) biogenesis in either source or recipient tissue, we detected endogenous and transgene specific sRNA that moved across the graft union. Surprisingly we found that the mobile endogenous sRNAs account for a substantial proportion of the sRNA in roots and we provide evidence that 24nt mobile sRNAs direct epigenetic modifications in the genome of the recipient cells. Mobile sRNA thus represents a mechanism for transmitting the specification of epigenetic modification and could affect genome defence and responses to external stimuli that have persistent effects in plants. Keywords: Small RNA Analysis, Epigenetics Overall design: 34 unique samples, 15 Biological Replicates

携带RNA特异性决定因子的植物沉默信号可通过胞间连丝与韧皮部进行传递。为鉴定可移动RNA，我们将拟南芥（Arabidopsis thaliana）的地上部分嫁接到可作为沉默信号受体的根部组织上。本研究采用灵敏度优异的高通量测序（high throughput sequencing）技术作为检测手段，并利用在供体或受体组织中阻断小RNA（sRNA）生物发生的突变体，成功检测到跨嫁接接合部移动的内源及转基因特异性小RNA。令人意外的是，我们发现可移动内源小RNA在根部小RNA总量中占相当大的比例；同时我们提供证据表明，24nt的可移动小RNA可在受体细胞的基因组中介导表观遗传修饰。因此，可移动小RNA代表了一种传递表观遗传修饰特异性的机制，或可影响植物的基因组防御以及对外界刺激产生具有持久性效应的应答反应。
关键词：小RNA分析、表观遗传学
实验整体设计：共34个独立样本，包含15次生物学重复