Small RNA sequencing of a complex of parasitic plant, Cuscuta japonica and Glycine max.

Cuscuta japonica is a stem parasitic plant that has a broad host range. It is widely accepted that parasitic plants and host plants exchange various molecules not only water and minerals, but also proteins, peptides, mRNAs and small RNAs. In order to elucidate the biological significance of sRNA exchange, we performed sRNA sequencing of a complex consisting of a parasitic plant, Cuscuta japonica, and a host plant, Glycine max, in order to prioritize sRNAs that were translocated from host to parasite, and vice versa. RNA samples were prepared from the parasitic interface, C. japonica stem distant from the parasitic interface, G. max stem distant from the parasitic junction, non-parasitized C. japonica stem, and non-parasitized G. max stem. Candidates for host-to-parasite mobile sRNAs were identified by mapping C. japonica reads from parasitized stem onto G. max reference transcriptome. On the other hand, candidates for parasite-to-host mobile sRNAs were identified by mapping G. max reads from parasitized stem to C. japonica reference transcriptome.

日本菟丝子（Cuscuta japonica）是一类寄主范围广泛的茎寄生植物。目前学界普遍认为，寄生植物与寄主植物之间不仅会交换水分与矿质元素，还会传递蛋白质、多肽、信使RNA（mRNA）以及小RNA（small RNA，sRNA）等多种分子。为阐明sRNA跨物种交换的生物学意义，本研究对由寄生植物日本菟丝子与寄主植物大豆（Glycine max）组成的寄生复合体开展了sRNA测序，以筛选出从寄主向寄生植物转运以及反向转运的sRNA候选序列。本研究从以下五类材料中提取了RNA样本：寄生界面、远离寄生界面的日本菟丝子茎段、远离寄生接合处的大豆茎段、未被寄生的日本菟丝子茎段，以及未被寄生的大豆茎段。通过将取自被寄生茎段的日本菟丝子测序读段（reads）比对至大豆参考转录组，本研究鉴定出寄主向寄生植物移动的sRNA候选序列。另一方面，通过将取自被寄生茎段的大豆测序读段比对至日本菟丝子参考转录组，本研究鉴定出寄生植物向寄主移动的sRNA候选序列。