Zhang Dandan, Liu Muxing, Tang Mingzhi, Dong Bo, Wu Dianxing, Zhang Zhengguang, Zhou Bo
State Key Laboratory of Rice Biology and Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou 310029, China; State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
Plant Sci. 2015 Aug;237:24-32. doi: 10.1016/j.plantsci.2015.05.002. Epub 2015 May 11.
The RNaseIII enzyme Dicer-like 1 (DCL1) processes the microRNA biogenesis and plays a determinant role in plant development. In this study, we reported the function of OsDCL1 in the immunity to rice blast, the devastating disease caused by the fungal pathogen, Magnaporthe oryzae. Expression profiling demonstrated that different OsDCLs responded dynamically and OsDCL1 reduced its expression upon the challenge of rice blast pathogen. In contrast, miR162a predicted to target OsDCL1 increased its expression, implying a negative feedback loop between OsDCL1 and miR162a in rice. In addition to developmental defects, the OsDCL1-silencing mutants showed enhanced resistance to virulent rice blast strains in a non-race specific manner. Accumulation of hydrogen peroxide and cell death were observed in the contact cells with infectious hyphae, revealing that silencing of OsDCL1 activated cellular defense responses. In OsDCL1 RNAi lines, 12 differentially expressed miRNAs were identified, of which 5 and 7 were down- and up-regulated, respectively, indicating that miRNAs responded dynamically in the interaction between rice and rice blast. Moreover, silencing of OsDCL1 activated the constitutive expression of defense related genes. Taken together, our results indicate that rice is capable of activating basal resistance against rice blast by perturbing OsDCL1-dependent miRNA biogenesis pathway.
核糖核酸酶III（RNaseIII）类酶Dicer样1（DCL1）参与微小RNA的生物合成过程，并在植物发育中起决定性作用。在本研究中，我们报道了水稻DCL1（OsDCL1）在水稻对稻瘟病免疫中的功能，稻瘟病是由真菌病原体稻瘟病菌（Magnaporthe oryzae）引起的毁灭性病害。表达谱分析表明，不同的OsDCL呈现动态响应，且在稻瘟病病原体侵染时OsDCL1的表达降低。相反，预测靶向OsDCL1的miR162a表达增加，这意味着水稻中OsDCL1与miR162a之间存在负反馈环。除了发育缺陷外，OsDCL1沉默突变体对强毒稻瘟病菌株表现出非小种特异性的抗性增强。在与侵染性菌丝接触的细胞中观察到过氧化氢积累和细胞死亡，这表明OsDCL1沉默激活了细胞防御反应。在OsDCL1 RNA干扰株系中，鉴定出12个差异表达的微小RNA，其中5个下调，7个上调，表明微小RNA在水稻与稻瘟病菌的互作中呈现动态响应。此外，OsDCL1沉默激活了防御相关基因的组成型表达。综上所述，我们的结果表明，水稻能够通过干扰依赖OsDCL1的微小RNA生物合成途径来激活对稻瘟病的基础抗性。
