Search

This study was designed to assess the suppressive effects of various anaerobically digested slurries (ADSs), and the microorganisms inhabiting them, against Fusarium wilt in spinach. We used five different ADSs from a range of source materials (dairy cow manure, sewage sludge, food garbage, pig manure, night soil sludge), combined in different proportions. All five raw ADSs suppressed the growth of Fusarium oxysporum f. sp. spinaciae (Fos) on agar plates using a co-culture test. In contrast, filtrate ADSs did not suppress the growth of Fos. In total, 32 bacterial strains were isolated from five ADSs, and eight isolates showed antagonistic activities against Fos. Based on 16S rDNA sequences, the strain AD-3 isolated from ADS from dairy cow manure belonged to Bacillus velezensis. Genome analysis revealed that AD-3 had two kinds of genes related to the production of the non-ribosomal lipopeptides, fengycin/plipastatin (pps genes), and surfactin (srf genes). In pot assays, inoculation of AD-3 (1.0 × 106 CFU·g−1 dry soil) into Fos-infected soil (1.0 × 105 bud-cells·g−1 dry soil) significantly reduced the severity of Fusarium wilt disease at 28 d after seedling. The percentage reductions in disease severity in two replicates were 64.3% and 44.3%, respectively. Thus, bacterial strain AD-3 could be applied to reduce Fusarium wilt in spinach. [ABSTRACT FROM AUTHOR]

This article presents an abstract of the paper "Studies on Diseases of Tropical Crops," which was presented by a winner of the Society Fellowship at the 2013 Annual Meeting of the Phytopathological Society of Japan in Gifu.

A new badnavirus, aucuba ringspot virus (AuRV), was identified in plants of Aucuba japonica showing mild mosaic, vein banding, and yellow ringspot symptoms on the leaves. The complete nucleotide sequence of the AuRV genome was determined and found to be 9,092 nt in length, and the virus was found to have a genome organization typical of members of the genus Badnavirus. ORF3 was predicted to encode a polyprotein containing conserved movement protein, coat protein, aspartic protease, reverse transcriptase (RT), and RNase H domains. Phylogenetic analysis suggested that this virus is most closely related to codonopsis vein clearing virus but belongs to a distinct species, based on only 69.6% nucleotide sequence identity within the part of ORF 3 encoding the RT and RNase H domains. The vector of AuRV is unknown, but based on phylogenetic relationships, it is predicted to be a type of aphid. [ABSTRACT FROM AUTHOR]

Bottle gourd [ Lagenaria siceraria (Mol.) Standl.] plants showing leaf mosaic and mottle were observed in Myanmar in 2007 and shown by RT-PCR and ELISA to be infected with Cucumber green mottle mosaic virus (CGMMV). This is the first report of the virus occurring in Myanmar. Despite considerable differences in geographical origins, natural host species and year of sampling of 22 CGMMV isolates, we found low genetic variation of the CP gene except for isolates GR3 and GR5, which showed similarity higher than 97%; based on the MP gene, and 16 CGMMV isolates showed similarity higher than 94% in nucleotide identities by pairwise comparison. Using MluI restriction endonuclease for CP genes, the CGMMV isolates fell into three types: Type I and Type II were included in the SH group and Type III in the W group. The two CGMMV isolates from Myanmar were found to belong to Type I and Type III, respectively. [ABSTRACT FROM AUTHOR]

A new nectrioid fungus with its sporodochial Cylindrocarpon anamorph, collected on dead bark of Luchu pines ( Pinus luchuensis) in the southern part of Japan (Kagoshima and Okinawa), having perithecia slightly constricted just below the papilla and conidia with a strongly hooked and acute apical cell, belongs to the genus Neonectria according to the recent concept of the Nectriaceae (Hypocreales). Molecular phylogenetic analysis based on the tub2 region of β-tubulin genes also supports the morphological consideration. This fungus is described as Neonectria amamiensis (anamorph: Cylindrocarpon amamiense). [ABSTRACT FROM AUTHOR]

The fungal population in the air and on developing fruit on a nonchemical banana farm in the Philippines was estimated from January 1998 to December 2001 to follow the source, determine the origin, and establish the population dynamics of various fungi associated with postharvest diseases of banana. Forty fungal genera were found in the air on a nonchemical banana farm and 26 were found on developing fruit. Spore density in the air and on the surface of developing fruit varied with seasonal patterns. Fungi of various species were detected on the farm and on developing banana fruit, but it has not been established as to when a specific fungus arrived at the farm and on the fruit. The results suggest that the source and origin of fungi associated with postharvest diseases of banana fruit in Japan imported from the Philippines were the farm itself, and the fungal association with banana fruit began at flower emergence. [ABSTRACT FROM AUTHOR]

Differences between Neonectria castaneicola, which causes stem and perennial canker of trees, and Neo. rugulosa have not been clearly shown in previous studies. In this study these two species were compared in detail using 17 Japanese isolates consisting of 10 strains of Neo. castaneicola and seven of Neo. rugulosa. Four-spored asci were constantly found in Neo. castaneicola and this species produced larger ascospores and macroconidia than Neo. rugulosa which produced eight-spored asci. The mating system of Neo. castaneicola was homothallic while Neo. rugulosa was heterothallic. Characters in each species, such as the number of ascospores in an ascus and mating system, were constantly transferred to the 3rd generation. Molecular analysis revealed that the 10 isolates of Neo. castaneicola and seven of Neo. rugulosa were differentiated using rDNA sequence data from the nuclear rDNA ITS region. Moreover, Neo. castaneicola and Neo. rugulosa were separated into different clades. From these results, it was concluded that Neo. castaneicola should be maintained as an independent species, separate from Neo. rugulosa. The isolates of Neo. rugulosa used in this study were the first reported in Japan and found on Castanea crenata, Castanopsis sp., Myrica rubra and Quercus acutissima. [ABSTRACT FROM AUTHOR]

Isolates ofBanana bunchy top virus(BBTV), which causes bunchy top disease in bananas, were collected in field surveys on seven islands in Okinawa Prefecture, Japan. From 44 banana samples, one isolate from each island was selected, and the DNA-1 and DNA-3 components were sequenced. Analysis of the major common region of DNA-1 showed that BBTV in Okinawa belongs to the Asian group of BBTV. DNA-1 and DNA-3 analysis revealed that Okinawan BBTV had a closer relationship with isolates from Taiwan and the Philippines than with some isolates from China and Vietnam. All the Okinawan BBTV isolates had high homology in the nucleotide sequences of DNA-1 and DNA-3 (%) because of a single, recent BBTV invasion of this area. [ABSTRACT FROM AUTHOR]

Rice yellow mottle virus (RYMV) causes severe rice (Oryza sativa L.) yield loss. It has been endemic to sub-Saharan Africa and Madagascar since 1966. Transmission (plant community level) and long-dispersal (regional and continental scale) models have been established but viral spread in farming communities continues, while the conditions causing local disease outbreaks remain unclear. We hypothesized that local outbreaks, comprising inter-plot virus spread and intra-plot disease aggravation, are significantly associated with individual farmers' attributes and agronomic practices. To test this hypothesis, spatial autoregressive models were constructed using variables collected by visual observation and farmer interviews. Field surveys were conducted during four consecutive cropping seasons from 2011 to 2013 in the Lower Moshi Irrigation Scheme of Kilimanjaro, Tanzania. Our models detected spatial dependence in inter-plot virus spread, but not in intra-plot disease aggravation. The probability of inter-plot virus spread increased with use of the IR64 cultivar (26.9%), but decreased with straw removal (27.8%) and crop rotation (47.7%). The probability of intra-plot disease aggravation decreased with herbicide application (24.3%) and crop rotation (35.4%). A simple cost-benefit analysis suggested that inter-plot virus spread should be mitigated by cultivar replacement and straw removal. When disease severity is critical, intra-plot disease aggravation should be inhibited by herbicide application, and rice should be rotated with other crops. This is the first study to upscale the spatial autoregressive model from the experimental field level to the farming community level, by obtaining variables through easy-to-implement techniques such as visual observation and farmer interview. Our models successfully identified candidate agronomic practices for the control of RYMV. However, as the causal relationships between agronomic practices and RYMV outbreaks remain unknown, field trials are needed to develop robust control measures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A potyvirus with the proposed name ashitaba mosaic virus was detected in ashitaba [Angelica keiskei (Miq.)] plants exhibiting mosaic and vein clearing in Japan. The host range of the virus includes species from three families, Apiaceae, Chenopodiaceae, and Solanaceae. The genome of the virus was determined to comprise 9,651 nucleotides, excluding the poly(A) tail. A phylogenetic analysis based on the polyprotein revealed the virus is closely related to carrot thin leaf virus and potyviruses isolated from Apiales and Apiaceae plant species. Sequence comparisons indicated the nucleotide and polyprotein amino acid identities between the isolated virus and related species are 53.4–60.5% and 49.7–58.7%, respectively. These results suggest this virus is a new species in the genus Potyvirus. Furthermore, the results of a field survey suggest the virus may be widespread on the Izu Islands, with isolates classified into two genotypes. [ABSTRACT FROM AUTHOR]

New perennial canker diseases ofAbies veitchiiandAcer crataegifoliumare described. Pathogenicity of the causal fungus was confirmed on stems of youngAbiesandAcertrees using two monoascospore isolates from the perithecia from the two tree species. The causal fungus, producingNectria-state-teleomorph andCylindrocarpon-anamorph, was identified asNectria castaneicola. It was then transferred to the genusNeonectria, asN. castaneicola(W. Yamam. et Oyasu) Tak. Kobay. et Hirooka, comb. nov. followed by the recent concept of Nectriaceae. [ABSTRACT FROM AUTHOR]

In 2016, in Miyakojima, Okinawa, Japan, banana plants (Musa × paradisiaca) ‘Shima-banana’ developed yellowing and wilt associated with vascular discoloration of the pseudostems. Fusarium oxysporum, identified based on morphological characters, was frequently isolated from the vascular tissue of the infected plant and reproduced the original symptoms on ‘Shima-banana’ after drench inoculation with a spore suspension. Thereby, we determined that the disease is Panama disease caused by F. oxysporum. This is the first official report of Panama disease (Panama-byo in Japanese) of banana in Japan. [ABSTRACT FROM AUTHOR]

We investigated the occurrence of insect pests and natural enemies on rice plants and weeds around rice fields in Uganda, East Africa, during 2010 and 2013. The following pest arthropods were collected with an insect net: large-sized stalk-eyed fly (Diopsis longicornis), small-sized stalk-eyed fly (D. apicalis), plant bugs (Pentatomidae and Alydidae), planthoppers and leafhoppers (Delphacidae and Cicadellidae), leaf beetles (Chaetocnema spp., Chrysispa viridicyanea and Altica spp.), short-horned grasshoppers (Coryphosima spp. etc.) and long-horned grasshoppers (Tettigoniidae). Small-sized natural enemies, such as parasitic wasps (Hymenoptera: Eulophidae, Cynipoidea, Braconidae and Ichneumonidae), were also captured. [ABSTRACT FROM AUTHOR]

Tobacco leaf curl Japan virus, Honeysuckle yellow vein mosaic virus and Tomato yellow leaf curl virus are three begomoviruses that infect tomato crops in Japan. Tomato infection by begomoviruses has increased in Japan after the development of a high level of resistance to certain insecticides in some populations of the vector B. tabaci biotypes 'B and Q'. Ty-1 and Ty-2 homozygous tomato hybrids were evaluated for reaction to monopartite begomovirus species in Japan by Agrobacterium-mediated inoculation. Test plants were evaluated by a disease assessment scale ( DAS), varying from 1 = no symptoms to 4 = severe symptoms, and systemic infection was evaluated by polymerase chain reaction ( PCR), using specific begomovirus primers for each virus. Ty-1 hybrids showed tolerance to HYVMV and with a large number of plants being neither virus-free nor symptom-free. The response of Ty-1 hybrids was also resistant to moderately resistant against Tb LCJV. The response of Ty-2 hybrids was resistant to highly resistant against the three monopartite begomoviruses, when compared with susceptible plants. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV) has been reported from potato production areas in Europe, USA, Japan and more frequently in regions with warm climates such as Egypt, India, Saudi Arabia and Syria. As it is considered as an uncommon virus in potato, the characterization of potato isolates of CMV is far behind those from other hosts. In addition to potato, CMV is a common virus infecting many crops in Syria, but nothing is known about its molecular characteristics. The present study aimed to characterize Syrian CMV isolates collected from potato and neighboring tobacco fields. All potato isolates of CMV (total of four) co-infected potato plants with Potato virus Y (PVY) which is the most frequent potato virus in Syria. According to the sequence analyses of the coat protein (CP) coding region, three potato and three tobacco CMV isolates were found to be closely related regardless of the host species or geographic origin, and all belonged to the IA strain subgroup of CMV. A potato CMV isolate, PoCMV7-5, readily infected solanaceous plants in which it induced systemic infection, but was less infectious to other hosts including those of Leguminosae and Cucurbitaceae. When inoculated on potato plants, PoCMV7-5 alone or with various PVY strains was able to cause local but not systemic infection in all potato cultivars inoculated. PoCMV7-5 contained heterogeneous variants of satellite RNA which varied in length due to A or/and T deletion/ insertion at approximate nucleotide position 225-240. This is the first report on CMV satellite RNA from potato. [ABSTRACT FROM AUTHOR]

A putative Potexvirus was detected from bottle gourd (Lagenaria siceraria) showing mosaic and mottle symptoms in Myanmar in 2007. The virus was designated Lagenaria mild mosaic virus (LaMMoV) and was further characterized. In artificial inoculation tests, infectivity of LaMMoV was limited to two families: Chenopodiaceae and Cucurbitaceae. The host range of LaMMoV differs from those of the two cucurbit-infecting potexviruses, Alternanthera mosaic virus (AltMV) and Papaya mosaic virus (PapMV). Sequence analyses of LaMMoV showed that the C-terminal 3,859 nucleotides, excluding the poly-A tail, includes the C-terminal region of an RNA-dependent RNA polymerase (RdRp), a triple gene block (TaB), a coat protein (CP), and a 3' untranslated region (UTR), all of which are typical of potexviruses. Although LaMMoV is related closely to AltMV and PapMV, its nucleotide sequences differ from those of other previously reported potexviruses. Therefore, we report LaMMoV as a new species of the genus Potexvirus that occurs in the cucurbit bottle gourd. [ABSTRACT FROM AUTHOR]

Based on inoculation experiments and morphological and molecular phylogenetic studies, Cylindrocladium damping-off of strawberry and Cylindrocladium blight of coral bells in Japan were demonstrated to be caused by Cylindrocladium canadense. This is the first report of a disease on strawberry and coral bells caused by this fungus. [ABSTRACT FROM AUTHOR]

Brown leaf spot disease caused by Cylindrocladium was found on Howea belmoreana on Hachijojima Island, Tokyo, Japan, in December 2001. Typical symptoms were incited after artificial inoculation. A culture of white mycelia, isolated from leaf spot symptoms, produced reddish perithecia of a nectriaceous fungus. Based on morphological and molecular analyses, this fungus was identified as Calonectria ilicicola (anamorph: Cylindrocladium parasiticum). Pathogenicity of this fungus on five plants cultivated on Hachijojima Island was confirmed by artificial inoculation. This report is the first on Cylindrocladium brown leaf spot of H. belmoreana caused by C. ilicicola (anamorph: Cy. parasiticum). [ABSTRACT FROM AUTHOR]

We isolated 629 fungi from 1296 berry seeds of solanaceous plants, including tomato ( Lycopersicon esculentum), eggplant ( Solanum melongena), bell pepper ( Capsicum annuum), and red pepper ( Capsicum annuum var. annuum) preserved for long and short terms. The isolates were classified into 22 genera excluding unidentified fungi, and the fungal floras were divided into two types: the tomato–eggplant and pepper groups. The results of cluster analysis with unweighted pair-group method with arithmetic average also supported these groups. Most tomato seeds infested with Geotrichum candidum germinated and grew the same as uninfested seeds. Cladosporium sphaerospermum and Arthrinium sp. isolated from eggplant seeds strongly suppressed germination, and Penicillium variabile suppressed seminal root elongation on eggplant. Alternaria alternata, Botrytis cinerea, and Myrothecium verrucaria detected from red pepper or bell pepper seeds were pathogenic to the fruits and the seedlings after artificial inoculation. [ABSTRACT FROM AUTHOR]

• Fluorescent LAMP assay using dried-reagent for Sri Lankan cassava mosaic virus was developed. • The LAMP sensitivity was 10,000 times higher than PCR assay. • The LAMP detected SLCMV from a leaf and stem without DNA extraction. • On-site detection of SLCMV was available using dried LAMP kit and thermos bottle. Recently, the widespread occurrence of Sri Lankan cassava mosaic virus (SLCMV), genus Begomovirus , family Geminiviridae , which causes a mosaic disease in cassava (Manihot esculenta Crantz) in South-East Asia have, become a serious economic issue. Since cassava is propagated through vegetative cuttings, a rapid virus diagnostic method is crucial for generating virus-free planting materials. In this study, a loop-mediated isothermal amplification (LAMP) assay using six primers was developed and validated for the rapid detection of SLCMV in cassava leaves. This SLCMV assay had a detection sensitivity that was up to 10,000 times higher than that of the conventional polymerase chain reaction assay and can detect the virus from symptomless stem cutting, which is a potential long-distance spreader of the virus. Furthermore, a practical LAMP protocol using stable dried reagents from a commercial kit was established so that the assay could be performed in the field by incubating the reactions in water at 60–65 °C instead of using a thermal cycler. The primer sequences and the LAMP protocol described here should be useful for the rapid and sensitive on-site detection of SLCMV. [ABSTRACT FROM AUTHOR]