Significantly low level of small RNA accumulation derived from an encapsidated mycovirus with dsRNA genome

AbstractThe role of RNA silencing as an antiviral defence has been well elucidated in plants and invertebrates, but not in filamentous fungi. We have previously determined the complete genome sequence of Magnaporthe oryzae virus 2 (MoV2), a dsRNA virus that infects the rice blast fungus Magnaporthe oryzae. In this study, we detected small interfering RNAs (siRNAs) from both positive- and negative-strand MoV2 viral RNA, suggesting that the RNA silencing machinery in M. oryzae functions against the mycovirus. Cloning and characterisation of MoV2 siRNAs indicated that, in MoV2, the ratio of virus-derived siRNAs to total small RNA is significantly lower than that in either plant viruses or Cryphonectria hypovirus 1 (CHV1), another mycovirus. Nevertheless, any MoV2-encoded proteins did not exhibit RNA silencing suppressor activity in both the plant and fungal systems. Our study suggests the existence of a novel viral strategy employed to evade host RNA silencing

Plant viruses and viroids in Japan

An increasing number of plant viruses and viroids have been reported from all over the world due largely to metavirogenomics approaches with technological innovation. Herein, the official changes of virus taxonomy, including the establishment of megataxonomy and amendments of the codes of virus classification and nomenclature, recently made by the International Committee on Taxonomy of Viruses were summarized. The continued efforts of the plant virology community of Japan to index all plant viruses and viroids occurring in Japan, which represent 407 viruses, including 303 virus species and 104 unclassified viruses, and 25 viroids, including 20 species and 5 unclassified viroids, as of October 2021, were also introduced. These viruses and viroids are collectively classified into 81 genera within 26 families of 3 kingdoms (Shotokuvirae, Orthornavirae, Pararnavirae) across 2 realms (Monodnaviria and Riboviria). This review also overviewed how Japan’s plant virus/viroid studies have contributed to advance virus/viroid taxonomy

Dramatic Transcriptional Changes in an Intracellular Parasite Enable Host Switching between Plant and Insect

Phytoplasmas are bacterial plant pathogens that have devastating effects on the yields of crops and plants worldwide. They are intracellular parasites of both plants and insects, and are spread among plants by insects. How phytoplasmas can adapt to two diverse environments is of considerable interest; however, the mechanisms enabling the “host switching” between plant and insect hosts are poorly understood. Here, we report that phytoplasmas dramatically alter their gene expression in response to “host switching” between plant and insect. We performed a detailed characterization of the dramatic change that occurs in the gene expression profile of Candidatus Phytoplasma asteris OY-M strain (approximately 33% of the genes change) upon host switching between plant and insect. The phytoplasma may use transporters, secreted proteins, and metabolic enzymes in a host-specific manner. As phytoplasmas reside within the host cell, the proteins secreted from phytoplasmas are thought to play crucial roles in the interplay between phytoplasmas and host cells. Our microarray analysis revealed that the expression of the gene encoding the secreted protein PAM486 was highly upregulated in the plant host, which is also observed by immunohistochemical analysis, suggesting that this protein functions mainly when the phytoplasma grows in the plant host. Additionally, phytoplasma growth in planta was partially suppressed by an inhibitor of the MscL osmotic channel that is highly expressed in the plant host, suggesting that the osmotic channel might play an important role in survival in the plant host. These results also suggest that the elucidation of “host switching” mechanism may contribute to the development of novel pest controls

New Detection Systems of Bacteria Using Highly Selective Media Designed by SMART: Selective Medium-Design Algorithm Restricted by Two Constraints

Culturing is an indispensable technique in microbiological research, and culturing with selective media has played a crucial role in the detection of pathogenic microorganisms and the isolation of commercially useful microorganisms from environmental samples. Although numerous selective media have been developed in empirical studies, unintended microorganisms often grow on such media probably due to the enormous numbers of microorganisms in the environment. Here, we present a novel strategy for designing highly selective media based on two selective agents, a carbon source and antimicrobials. We named our strategy SMART for highly Selective Medium-design Algorithm Restricted by Two constraints. To test whether the SMART method is applicable to a wide range of microorganisms, we developed selective media for Burkholderia glumae, Acidovorax avenae, Pectobacterium carotovorum, Ralstonia solanacearum, and Xanthomonas campestris. The series of media developed by SMART specifically allowed growth of the targeted bacteria. Because these selective media exhibited high specificity for growth of the target bacteria compared to established selective media, we applied three notable detection technologies: paper-based, flow cytometry-based, and color change-based detection systems for target bacteria species. SMART facilitates not only the development of novel techniques for detecting specific bacteria, but also our understanding of the ecology and epidemiology of the targeted bacteria

Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF) 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species

Evaluation of Simultaneous Dual-radioisotope SPECT Imaging Using 18F-fluorodeoxyglucose and 99mTc-tetrofosmin

Objective(s): Use of a positron emission tomography (PET)/single-photonemission computed tomography (SPECT) system facilitates the simultaneousacquisition of images with fluorine-18 fluorodeoxyglucose (18F-FDG) andtechnetium (99mTc)-tetrofosmin. However, 18F has a short half-life, and 511keV Compton-scattered photons are detected in the 99mTc energy window.Therefore, in this study, we aimed to investigate the consequences of thesefacts.Methods: The crosstalk correction for images in the 99mTc energy windowinvolved the dual energy window (DEW) subtraction method. In phantomstudies, changes in the count of uniform parts in a phantom (due to attenuationfrom decay), signal detectability in the hot-rod part of the phantom, and thedefect contrast ratio in a cardiac phantom were examined.Results: For 18F-FDG in the step-and-shoot mode, nearly a 9% difference wasobserved in the count of projection data between the start and end positionsof acquisition in the uniform part of the phantom. Based on the findings,the detectability of 12 mm hot rods was relatively poor. In the continuousacquisition mode, the count difference was corrected, and detectability of thehot rods was improved. The crosstalk from 18F to the 99mTc energy windowwas approximately 13%. In the cardiac phantom, the defect contrast in 99mTcimages from simultaneous dual-radionuclide acquisition was improved byapproximately 9% after DEW correction; the contrast after correction wassimilar to acquisition with 99mTc alone.Conclusion: Based on the findings, the continuous mode is useful for 18F-FDGacquisition, and DEW crosstalk correction is necessary for 99mTc-tetrofosminimaging

List of roles and number of appearances in eight repositories.

List of roles and number of appearances in eight repositories.</p

List of data curation activities by field.

In recent years, with the trend of open science, there have been many efforts to share research data on the internet. To promote research data sharing, data curation is essential to make the data interpretable and reusable. In research fields such as life sciences, earth sciences, and social sciences, tasks and procedures have been already developed to implement efficient data curation to meet the needs and customs of individual research fields. However, not only data sharing within research fields but also interdisciplinary data sharing is required to promote open science. For this purpose, knowledge of data curation across the research fields is surveyed, analyzed, and organized as an ontology in this paper. As the survey, existing vocabularies and procedures are collected and compared as well as interviews with the data curators in research institutes in different fields are conducted to clarify commonalities and differences in data curation across the research fields. It turned out that the granularity of tasks and procedures that constitute the building blocks of data curation is not formalized. Without a method to overcome this gap, it will be challenging to promote interdisciplinary reuse of research data. Based on the analysis above, the ontology for the data curation process is proposed to describe data curation processes in different fields universally. It is described by OWL and shown as valid and consistent from the logical viewpoint. The ontology successfully represents data curation activities as the processes in the different fields acquired by the interviews. It is also helpful to identify the functions of the systems to support the data curation process. This study contributes to building a knowledge framework for an interdisciplinary understanding of data curation activities in different fields.</div