Department of Biological Sciences, University of Lethbridge, University Drive 4401, Lethbridge, Alberta, Canada.
Plant Cell Rep. 2010 Dec;29(12):1401-10. doi: 10.1007/s00299-010-0930-9. Epub 2010 Oct 16.
Plant response to stress has been linked to different RNA-silencing processes and epigenetic mechanisms. Our recent results showed that Arabidopsis thaliana Dicer-like (DCL) mutants were impaired in transgenerational changes, recombination frequency and stress tolerance. We also found that transgenerational changes were dependent on changes in DNA methylation. Here, we hypothesized that plants deficient in the production of small RNAs would show an impaired abiotic stress response. To test this, we exposed A. thaliana dcl2, dcl3, dcl4, dcl2 dcl3 (d2d3), dcl2 dcl4 (d2d4), dcl2 dcl3 dcl4 (d2d3d4), nrpd1a, rdr2 and rdr6 mutants to methyl methane sulfonate (MMS). We found dcl4 and rdr6 to be more sensitive and dcl2, dcl3, d2d3 and rdr2 plants more resistant to MMS, as shown by fresh weight, root length and survival rate. The in vitro repair assay showed the lower ability of dcl2 and dcl3 to repair UV-damaged DNA. To summarize, we found that whereas mutants impaired in transactivating siRNA biogenesis were more sensitive to MMS, mutants impaired in natural antisense siRNA and heterochromatic siRNA biogeneses were more tolerant. Our data suggest that plant response to MMS is in part regulated through biogenesis of various siRNAs.
植物对胁迫的反应与不同的 RNA 沉默过程和表观遗传机制有关。我们最近的结果表明，拟南芥 Dicer-like (DCL) 突变体在跨代变化、重组频率和应激耐受性方面存在缺陷。我们还发现，跨代变化依赖于 DNA 甲基化的变化。在这里，我们假设缺乏小 RNA 产生的植物会表现出受损的非生物胁迫反应。为了验证这一点，我们使拟南芥 dcl2、dcl3、dcl4、dcl2 dcl3(d2d3)、dcl2 dcl4(d2d4)、dcl2 dcl3 dcl4(d2d3d4)、nrpd1a、rdr2 和 rdr6 突变体暴露于甲基甲烷磺酸酯 (MMS) 中。我们发现 dcl4 和 rdr6 对 MMS 更敏感，而 dcl2、dcl3、d2d3 和 rdr2 植物对 MMS 的抗性更强，表现在鲜重、根长和存活率上。体外修复实验表明，dcl2 和 dcl3 修复 UV 损伤 DNA的能力较低。总之，我们发现，尽管突变体在反式激活 siRNA 生物发生方面存在缺陷，对 MMS 更敏感，但在天然反义 siRNA 和异染色质 siRNA 生物发生方面存在缺陷的突变体对 MMS 更耐受。我们的数据表明，植物对 MMS 的反应部分受各种 siRNA 生物发生的调节。
