Detection of Alternaria solani with high accuracy and sensitivity during the latent period of potato early blight.

Early blight (EB) disease, caused mainly by Alternaria solani, is an economic threat to potato and tomato production worldwide. Thus, accurate and sensitive detection of the fungal pathogen of this disease in plants at the early infection stage is important for forecasting EB epidemics. In this study, we developed an RNA-based method that enables highly accurate and sensitive A. solani detection in a whole potato leaf at a single spore level based on quantitative real-time polymerase chain reaction (qPCR). We discovered jg1677, a highly expressed gene whose full-length coding sequence is very specific for A. solani, by analyzing A. solani transcripts isolated from enhanced high throughput transcriptome of infected potato leaves by A. solani and using the National Center for Biotechnology Information's basic local alignment search tool. The specificity of the primers derived from jg1677 was determined using 22 isolates of common potato pathogens, including seven Alternaria isolates. Detecting jg1677 transcripts with qPCR is 1,295 times more sensitive than detecting genomic DNA. In addition, the expression pattern of jg1677 at different infection stages was determined by qPCR. What is more, jg1677 was expressed relatively stable between 15 and 35°C in infected leaves, and its expression was virtually unaffected in isolated leaves left at room temperature for 24 h. Our work provides a much more sensitive and accurate method compared to conditional DNA-based ones, permitting a very early diagnosis of EB and lowering the risk of EB epidemics.

[Enlightenment on Carrying out Reporting Responsibility of Manufactures in China from Reviewing Medical Device Reporting Practice in US].

OBJECTIVE: By introducing the Medical Device Reporting (MDR) system and related inspection practice of the US, this paper puts forward some suggestions on implementing reporting responsibility of manufactures in China. METHODS: The MDR system and the related inspection system in the US were systematically analyzed. RESULTS: The US had established a sound system for discovering and reporting MDR, and a mechanism for inspecting the implementing of manufactures, forming an effective post-market surveillance system. CONCLUSIONS: By learning from the experience of the US, we can carry out the post-market surveillance of medical devices adverse events in China from the aspects of implementing the existing system, strengthening the reporting ability and perfecting the inspection mechanism.

Detecting the Interaction of Double-stranded RNA Binding Protein, Viral Protein and Primary miRNA Transcript by Co-immunoprecipitation in planta.

MicroRNAs (miRNAs) play important roles in plant growth, development, and response to infection by microbes. Double-stranded RNA binding protein 1 (DRB1) facilitates the processing of primary miRNA transcripts into mature miRNAs. Recently, we found that NS3 protein encoded by rice stripe virus (RSV) associates with DRB1 and promotes miRNA biogenesis during RSV infection ( Zheng et al., 2017 ). RNA co-immunoprecipitation (RIP) method was applied to identity association patterns among DRB1, NS3, and miRNA transcript.

Rice stripe virus NS3 protein regulates primary miRNA processing through association with the miRNA biogenesis factor OsDRB1 and facilitates virus infection in rice.

MicroRNAs (miRNAs) are small regulatory RNAs processed from primary miRNA transcripts, and plant miRNAs play important roles in plant growth, development, and response to infection by microbes. Microbial infections broadly alter miRNA biogenesis, but the underlying mechanisms remain poorly understood. In this study, we report that the Rice stripe virus (RSV)-encoded nonstructural protein 3 (NS3) interacts with OsDRB1, an indispensable component of the rice (Oryza sativa) miRNA-processing complex. Moreover, the NS3-OsDRB1 interaction occurs at the sites required for OsDRB1 self-interaction, which is essential for miRNA biogenesis. Further analysis revealed that NS3 acts as a scaffold between OsDRB1 and pri-miRNAs to regulate their association and aids in vivo processing of pri-miRNAs. Genetic evidence in Arabidopsis showed that NS3 can partially substitute for the function of double-stranded RNA binding domain (dsRBD) of AtDRB1/AtHYL1 during miRNA biogenesis. As a result, NS3 induces the accumulation of several miRNAs, most of which target pivotal genes associated with development or pathogen resistance. In contrast, a mutant version of NS3 (mNS3), which still associated with OsDRB1 but has defects in pri-miRNA binding, reduces accumulation of these miRNAs. Transgenic rice lines expressing NS3 exhibited significantly higher susceptibility to RSV infection compared with non-transgenic wild-type plants, whereas the transgenic lines expressing mNS3 showed a less-sensitive response. Our findings revealed a previously unknown mechanism in which a viral protein hijacks OsDRB1, a key component of the processing complex, for miRNA biogenesis and enhances viral infection and pathogenesis in rice.

Viral-inducible Argonaute18 confers broad-spectrum virus resistance in rice by sequestering a host microRNA.

Viral pathogens are a major threat to rice production worldwide. Although RNA interference (RNAi) is known to mediate antiviral immunity in plant and animal models, the mechanism of antiviral RNAi in rice and other economically important crops is poorly understood. Here, we report that rice resistance to evolutionarily diverse viruses requires Argonaute18 (AGO18). Genetic studies reveal that the antiviral function of AGO18 depends on its activity to sequester microRNA168 (miR168) to alleviate repression of rice AGO1 essential for antiviral RNAi. Expression of miR168-resistant AGO1a in ago18 background rescues or increases rice antiviral activity. Notably, stable transgenic expression of AGO18 confers broad-spectrum virus resistance in rice. Our findings uncover a novel cooperative antiviral activity of two distinct AGO proteins and suggest a new strategy for the control of viral diseases in rice.