MicroRNAs from the parasitic plant Cuscuta campestris target host messenger RNAs
MicroRNAs from the parasitic plant Cuscuta campestris target host messenger RNAs
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DOI：
10.1038/nature25027
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发表时间：
2018-01-04
期刊：
影响因子：
64.8
通讯作者：
Axtell, Michael J.
中科院分区：
文献类型：
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作者：
Shahid, Saima;Kim, Gunjune;Axtell, Michael J.
菟丝子（菟丝子）是专性寄生植物，通过称为吸器的特殊取食结构从寄主植物的茎中获取水分和营养。菟丝子吸器促进病毒、蛋白质和mrna在宿主和寄生虫之间的双向运动(1)，但这些运动的功能影响尚不清楚。本研究表明，吸虫Cuscuta campestris hastoria在寄生拟南芥（Arabidopsis thaliana）时积累了大量新的microRNAs （miRNAs）。许多这些mirna的长度为22个核苷酸。这种长度的植物mirna并不常见，并且与通过次级短干扰RNA （siRNA）产生的靶沉默扩增有关(2)。在寄生过程中，一些拟南芥mRNA被22个核苷酸的campestris miRNAs靶向，导致mRNA分裂，产生次级siRNA， mRNA积累减少。编码目标mrna的两个基因座发生突变的宿主支持campestris显著更高的生长。campestris寄生拟南芥时表达并活跃的mirna在其感染benthamiana时也表达并活跃。来自许多其他植物物种的靶mrna的同源物也含有诱导的campestris miRNAs的预测靶位。这些数据表明，campestris C. campestris miRNAs可以作为宿主基因表达的跨物种调节因子，并提示它们可能在寄生过程中起毒力因子的作用。
Dodders (Cuscuta spp.) are obligate parasitic plants that obtain water and nutrients from the stems of host plants via specialized feeding structures called haustoria. Dodder haustoria facilitate bidirectional movement of viruses, proteins and mRNAs between host and parasite(1), but the functional effects of these movements are not known. Here we show that Cuscuta campestris haustoria accumulate high levels of many novel microRNAs (miRNAs) while parasitizing Arabidopsis thaliana. Many of these miRNAs are 22 nucleotides in length. Plant miRNAs of this length are uncommon, and are associated with amplification of target silencing through secondary short interfering RNA (siRNA) production(2). Several A. thaliana mRNAs are targeted by 22-nucleotide C. campestris miRNAs during parasitism, resulting in mRNA cleavage, secondary siRNA production, and decreased mRNA accumulation. Hosts with mutations in two of the loci that encode target mRNAs supported significantly higher growth of C. campestris. The same miRNAs that are expressed and active when C. campestris parasitizes A. thaliana are also expressed and active when it infects Nicotiana benthamiana. Homologues of target mRNAs from many other plant species also contain the predicted target sites for the induced C. campestris miRNAs. These data show that C. campestris miRNAs act as trans-species regulators of host-gene expression, and suggest that they may act as virulence factors during parasitism.