Subhankar Bera, Yamaguchi Katsushi, Shigenobu Shuji, Aoki Koh
Gradute School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
Functional Genomics Facility, National Institute for Basic Biology (NIBB), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan.
Plant Biotechnol (Tokyo). 2021 Jun 25;38(2):187-196. doi: 10.5511/plantbiotechnology.21.0121a.
Parasitic plants exchange various types of RNAs with their host plants, including mRNA, and small non-coding RNA. Among small non-coding RNAs, miRNA production is known to be induced at the haustorial interface. The induced miRNAs transfer to the host plant and activate secondary siRNA production to silence target genes in the host. In addition to interfacial transfer, long-distance movement of the small RNAs has also been known to mediate signaling and regulate biological processes. In this study, we tested the long-distance movement of -species small RNAs in a parasitic-plant complex. Small RNA-Seq was performed using a complex of a stem parasitic plant, , and a host, . In the host plant's parasitized stem, genes involved in the production of secondary siRNA, and , were upregulated, and 22-nt small RNA was enriched concomitantly, suggesting the activation of secondary siRNA production. Stem-loop RT-PCR and subsequent sequencing experimentally confirmed the mobility of the small RNAs. -species mobile small RNAs were detected in the parasitic interface and also in distant organs. To clarify the mode of long-distance translocation, we examined whether -derived small RNA moves long distances in and mutants or not. Mobility of -derived small RNA in and mutants suggested the occurrence of direct long-distance transport without secondary siRNA production in the recipient plant.
寄生植物与寄主植物交换各种类型的RNA，包括信使核糖核酸（mRNA）和小非编码RNA。在小非编码RNA中，已知在吸器界面会诱导微小核糖核酸（miRNA）的产生。诱导产生的miRNA转移到寄主植物中，并激活次级小干扰核糖核酸（siRNA）的产生，从而使寄主中的靶基因沉默。除了界面转移外，小RNA的长距离移动也已知可介导信号传导并调节生物学过程。在本研究中，我们测试了寄生植物复合体中物种小RNA的长距离移动。使用一种茎寄生植物和一种寄主组成的复合体进行了小RNA测序。在寄主植物被寄生的茎中，参与次级siRNA产生的基因以及被上调，并且22核苷酸的小RNA同时富集，这表明次级siRNA产生被激活。茎环逆转录聚合酶链反应（Stem-loop RT-PCR）及随后的测序实验证实了小RNA的移动性。在寄生界面以及远处的器官中都检测到了物种移动性小RNA。为了阐明长距离转运的模式，我们研究了源自的小RNA在和突变体中是否能长距离移动。源自的小RNA在和突变体中的移动性表明，在受体植物中存在直接的长距离运输，而无需产生次级siRNA。
