National Engineering Research Center for Sugarcane, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.
College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.
Sci Rep. 2020 Aug 6;10(1):13202. doi: 10.1038/s41598-020-70061-7.
RNA silencing is a conserved mechanism in eukaryotic organisms to regulate gene expression. Argonaute (AGO), Dicer-like (DCL) and RNA-dependent RNA polymerase (RDR) proteins are critical components of RNA silencing, but how these gene families' functions in sugarcane were largely unknown. Most stress-resistance genes in modern sugarcane cultivars (Saccharum spp.) were originated from wild species of Saccharum, for example S. spontaneum. Here, we used genome-wide analysis and a phylogenetic approach to identify four DCL, 21 AGO and 11 RDR genes in the S. spontaneum genome (termed SsDCL, SsAGO and SsRDR, respectively). Several genes, particularly some of the SsAGOs, appeared to have undergone tandem or segmental duplications events. RNA-sequencing data revealed that four SsAGO genes (SsAGO18c, SsAGO18b, SsAGO10e and SsAGO6b) and three SsRDR genes (SsRDR2b, SsRDR2d and SsRDR3) tended to have preferential expression in stem tissue, while SsRDR5 was preferentially expressed in leaves. qRT-PCR analysis showed that SsAGO10c, SsDCL2 and SsRDR6b expressions were strongly upregulated, whereas that of SsAGO18b, SsRDR1a, SsRDR2b/2d and SsRDR5 was significantly depressed in S. spontaneum plants exposed to PEG-induced dehydration stress or infected with Xanthomonas albilineans, causal agent of leaf scald disease of sugarcane, suggesting that these genes play important roles in responses of S. spontaneum to biotic and abiotic stresses.
RNA 沉默是真核生物中调节基因表达的一种保守机制。Argonaute（AGO）、Dicer 样（DCL）和 RNA 依赖性 RNA 聚合酶（RDR）蛋白是 RNA 沉默的关键组成部分，但这些基因家族在甘蔗中的功能在很大程度上是未知的。现代甘蔗品种（Saccharum spp.）中的大多数抗逆性基因都来自野生甘蔗物种，例如 S. spontaneum。在这里，我们使用全基因组分析和系统发育方法在 S. spontaneum 基因组中鉴定了四个 DCL、21 个 AGO 和 11 个 RDR 基因（分别命名为 SsDCL、SsAGO 和 SsRDR）。一些基因，特别是一些 SsAGOs，似乎经历了串联或片段重复事件。RNA-seq 数据显示，四个 SsAGO 基因（SsAGO18c、SsAGO18b、SsAGO10e 和 SsAGO6b）和三个 SsRDR 基因（SsRDR2b、SsRDR2d 和 SsRDR3）在茎组织中表达偏好，而 SsRDR5 在叶片中表达偏好。qRT-PCR 分析表明，SsAGO10c、SsDCL2 和 SsRDR6b 的表达强烈上调，而 SsAGO18b、SsRDR1a、SsRDR2b/2d 和 SsRDR5 的表达在 S. spontaneum 植物暴露于 PEG 诱导的脱水胁迫或感染黄单胞菌（Xanthomonas albilineans）时显著下调，黄单胞菌是甘蔗叶烧病的病原体，这表明这些基因在 S. spontaneum 对生物和非生物胁迫的反应中发挥重要作用。
