Translocation of fungicides and their efficacy in controlling Phellinus noxius, the cause of brown root rot disease

Brown root rot disease (BRRD), caused by Phellinus noxius, is an important tree disease in tropical/subtropical areas. To improve chemical control of BRRD and deter emergence of fungicide resistance in P. noxius, this study investigated control efficacies and systemic activities of fungicides with different modes of action. Fourteen fungicides with 11 different modes of action were tested for inhibitory effects in vitro on 39 P. noxius isolates from Taiwan, Hong Kong, Malaysia, Australia, and Pacific Islands. Cyproconazole, epoxiconazole, and tebuconazole (FRAC 3, target-site G1) inhibited colony growth of P. noxius by 99.9 to 100% at 10 ppm and 97.7 to 99.8% at 1 ppm. The other effective fungicide was cyprodinil + fludioxonil (FRAC 9 + 12, target-site D1 + E2), which showed growth inhibition of 96.9% at 10 ppm and 88.6% at 1 ppm. Acropetal translocation of six selected fungicides was evaluated in bishop wood (Bischofia javanica) seedlings by immersion of the root tips in 100 ppm of each fungicide, followed by liquid or gas chromatography tandem-mass spectrometry analyses of consecutive segments of root, stem, and leaf tissues at 7- and 21-days post-treatment. Bi-directional translocation of the fungicides was also evaluated by stem injection of fungicide solutions. Cyproconazole and tebuconazole were the most readily absorbed by roots and efficiently transported acropetally. Greenhouse experiments suggested that cyproconazole, tebuconazole, and epoxiconazole have a slightly higher potential for controlling BRRD than mepronil, prochloraz, and cyprodinil + fludioxonil. Because all tested fungicides lacked basipetal translocation, soil drenching should be considered instead of trunk injection for their use in BRRD control.

[LONG-TERM RESULTS OF AIRBORNE POLLEN SURVEYS IN THE JAPANESE ARCHIPELAGO FROM THE PERSPECTIVE OF POLLEN ANTIGEN]

BACKGROUND

In 1986, the Ministry of Health and Welfare started an airborne pollen survey as part of measures against JC pollinosis. We reported the important tree pollen antigens in 2016. We have now estimated the longitudinal investigated results for successful prevention and treatment for allergic symptoms related to grass and weed pollen in Japan.

METHOD

Since July 1986 we have monitored airborne pollen, year- round, using a gravitational pollen sampler (Durham's sampler), at more than 20 locations across Japan. Specimens were mailed to our facility, where they were stained with Calberla solution, counted under an optical microscope, and converted to the number of pollen per square centimeter. For convenience the number of collected pollen were compiled every six months, with the January to June samples classified as spring pollen and the July to December as autumn pollen even same family.

RESULT

Total pollen counts at each location were extremely small compared to tree-pollen, averaging 73~650 pollen grains per year. The Sagamihara location had the greatest count. Unlike cedar and cypress there were no significant annual fluctuations, but grass and Ambrosia pollen counts are increasing in some regions. Spring grass pollen gave the largest count, at 30% of the total collected.

CONCLUSION

This indicated we need to examine the rinoconjuctivitis and oral allergy syndrome related to herbaceous pollen carefully.The importance of airborne pollen surveys for the treatment of the patients with pollen allergies was suggested.

LONGITUDINAL MONITORING OF TREE AIRBORNE POLLEN IN JAPAN

RATIONAL

In Japan patients with Japanese Cedar (JC) pollinosis have increased nation widely since the latter of 1970's. The Ministry of Health and Welfare of Japanese Governments has begun to take preventive measures against JC pollinosis and airborne pollen monitoring has begun to investigate as a causative agent since 1986. We have estimated the longitudinal investigation result for successful prevention and treatment against pollinosis in Japan.

METHOD

We have monitored airborne pollen all year around since July 1986 by gravitational pollen sampler, Durham's sampler, at more than 20 locations in the Japanese Islands. Pollen samples were sent to our hospital and counted pollen number per cm² after stained by Calberla solution and then classified main pollen grains as a causative agent of pollinosis.

RESULT AND DISCUSSION

JC pollen number was the most of all, more than 40%, next cypress family, about 20%. They were occupied of more than 60% of all and they increased with the remarkable annual fluctuation as the allergen of JC pollinosis. Beech family pollen counting were also increasing and occupied about 10% of all pollen counts. In Hokkaido the prevalence of birch family pollen count was larger than that in other districts. There is cross-reactivity between beech and birch family which related with oral allergic syndrome.Perspective and Conclusion: In future new occurrences of oral allergy syndrome due to increasing allergic tree pollen grains would be appeared. The contentious pollen research should be important for patients with pollinosis in Japan.

Genetic Differentiation and Spatial Structure of Phellinus noxius, the Causal Agent of Brown Root Rot of Woody Plants in Japan

Phellinus noxius is a pathogenic fungus that causes brown root rot disease in a variety of tree species. This fungus is distributed in tropical and sub-tropical regions of Southeast and East Asia, Oceania, Australia, Central America and Africa. In Japan, it was first discovered on Ishigaki Island in Okinawa Prefecture in 1988; since then, it has been found on several of the Ryukyu Islands. Recently, this fungus was identified from the Ogasawara (Bonin) Islands, where it has killed trees, including rare endemic tree species. For effective control or quarantine methods, it is important to clarify whether the Japanese populations of P. noxius are indigenous to the area or if they have been introduced from other areas. We developed 20 microsatellite markers from genome assembly of P. noxius and genotyped 128 isolates from 12 of the Ryukyu Islands and 3 of the Ogasawara Islands. All isolates had unique genotypes, indicating that basidiospore infection is a primary dissemination method for the formation of new disease foci. Genetic structure analyses strongly supported genetic differentiation between the Ryukyu populations and the Ogasawara populations of P. noxius. High polymorphism of microsatellite loci suggests that Japanese populations are indigenous or were introduced a very long time ago. We discuss differences in invasion patterns between the Ryukyu Islands and the Ogasawara Islands.

Comparative genomics of Taphrina fungi causing varying degrees of tumorous deformity in plants

Taphrina fungi are biotrophic plant pathogens that cause plant deformity diseases. We sequenced the genomes of four Taphrina species—Taphrina wiesneri, T. deformans, T. flavorubra, and T. populina—which parasitize Prunus, Cerasus, and Populus hosts with varying severity of disease symptoms. High levels of gene synteny within Taphrina species were observed, and our comparative analysis further revealed that these fungi may utilize multiple strategies in coping with the host environment that are also found in some specialized dimorphic species. These include species-specific aneuploidy and clusters of highly diverged secreted proteins located at subtelomeres. We also identified species differences in plant hormone biosynthesis pathways, which may contribute to varying degree of disease symptoms. The genomes provide a rich resource for investigation into Taphrina biology and evolutionary studies across the basal ascomycetes clade.

Virulence of Bursaphelenchus xylophilus Isolated from Naturally Infested Pine Forests to Five Resistant Families of Pinus thunbergii

Pine wilt disease is one of the most serious epidemic tree diseases in Japan, and resistant pine trees have been developed through a breeding program. To evaluate resistance of resistant families of Japanese black pine, Pinus thunbergii, to the pinewood nematode, Bursaphelenchus xylophilus, isolated from the field, and to determine whether differentiation of pathogenicity to resistant pine families appears in the nematode isolates, seedlings of five resistant pine families were inoculated with 25 nematode isolates. Disease incidence 18 weeks after inoculation was significantly different among nematode isolates and among pine families but there was no interaction effect between nematode isolate and pine family. This indicates that nematode isolates did not have differential host specificity to resistant families of P. thunbergii. Isolate Shimabara, a test isolate of the breeding program, showed the same degree of virulence as the highly virulent isolates frequently used in experiments. However, more virulent isolates than Shimabara were found among the isolates collected from natural pine forest. This indicated that B. xylophilus populations with higher virulence than Shimabara exist in the natural population. These findings are important in development of more efficient breeding procedures for resistant pine trees.

Genomic insights into the origin of parasitism in the emerging plant pathogen Bursaphelenchus xylophilus

Bursaphelenchus xylophilus is the nematode responsible for a devastating epidemic of pine wilt disease in Asia and Europe, and represents a recent, independent origin of plant parasitism in nematodes, ecologically and taxonomically distinct from other nematodes for which genomic data is available. As well as being an important pathogen, the B. xylophilus genome thus provides a unique opportunity to study the evolution and mechanism of plant parasitism. Here, we present a high-quality draft genome sequence from an inbred line of B. xylophilus, and use this to investigate the biological basis of its complex ecology which combines fungal feeding, plant parasitic and insect-associated stages. We focus particularly on putative parasitism genes as well as those linked to other key biological processes and demonstrate that B. xylophilus is well endowed with RNA interference effectors, peptidergic neurotransmitters (including the first description of ins genes in a parasite) stress response and developmental genes and has a contracted set of chemosensory receptors. B. xylophilus has the largest number of digestive proteases known for any nematode and displays expanded families of lysosome pathway genes, ABC transporters and cytochrome P450 pathway genes. This expansion in digestive and detoxification proteins may reflect the unusual diversity in foods it exploits and environments it encounters during its life cycle. In addition, B. xylophilus possesses a unique complement of plant cell wall modifying proteins acquired by horizontal gene transfer, underscoring the impact of this process on the evolution of plant parasitism by nematodes. Together with the lack of proteins homologous to effectors from other plant parasitic nematodes, this confirms the distinctive molecular basis of plant parasitism in the Bursaphelenchus lineage. The genome sequence of B. xylophilus adds to the diversity of genomic data for nematodes, and will be an important resource in understanding the biology of this unusual parasite.

Cross Inoculation Tests with Phellinus noxius Isolates from Nine Different Host Plants in the Ryukyu Islands, Southwestern Japan

Brown root rot, caused by Phellinus noxius, leads to problems in management of shade, ornamental, and windbreak trees in subtropical regions of the world, and it has been causing serious problems in Japan since 1988. To identify the pathogenicity, host specialization, and virulence of the pathogen, cross inoculation tests were carried out using isolates of the fungus obtained from nine different tree species. P. noxius was pathogenic to all of the nine tree species tested, and it killed inoculated seedlings. Among the 810 trees inoculated with the fungus, a total of 141 trees (17.4%), including all nine species, were dead within 110 days after inoculation. The first symptom of infection was rapid wilt with discoloration of leaves 20 to 30 days after inoculation, and then the plants quickly declined. Only one isolate of P. noxius that was tested caused significantly higher mortality in its original host than in other species, suggesting that the pathogen has little to no host specificity. However, the fungus did show variation in virulence, with the isolates originating in Bischofia javanica and Casuarina equisetifolia causing significantly higher mortality than those collected from other host species. More isolates of P. noxius from the same host species and/or from various countries should be studied to understand host specialization and virulence of the pathogen.

Quantitative analysis of antigen specific IgE in tears in comparison to serum samples

We determined pollen specific IgE in tears and compared these results to the concentration of specific IgE in serum samples. We obtained tears (using Schirmer strips) and serum samples from subjects with Japanese cedar (Cryptomeria japonica) pollinosis, and tested for C. japonica pollen specific IgE using a quantitative ELISA. Time kinetic analyses through the pollen season showed that specific IgE levels in tears were found to increase earlier than those in sera and reached their maximum at the end of or after the pollen season, from March to early June. In the C. japonica pollen free season, July to December, the specific IgE levels in tears decreased, although the serum levels remained relatively high. These results indicate that the quantitative assay for specific IgE in tears might be useful to identify specific eye allergens.

Erythritol-based dry powder of glucagon for pulmonary administration

Glucagon, a key regulatory element of glycogen metabolism, is known to be effective in the clinical treatment of hypoglycemia and the maintenance of normal circulating glucose levels in patients with total pancreatectomy, however the clinical use of this gut hormone has been restricted to parenteral administration. In this investigation, we prepared dry powder dosage forms of glucagon, which were formulated by mixing micronized glucagon particles and excipients with larger carrier particles. To achieve alveolar deposition for subsequent systemic absorption, a dry powder inhalant (DPI) of glucagon was size-reduced to a mass median diameter between 1 and 6 microm, as measured by laser diffraction analysis. The use of erythritol as both excipient and carrier in DPI of glucagon resulted in high and reproducible flowability and dispersibility of the powder mixtures, and therefore it provided a low dosing of the active substances. Distinct transpulmonary absorption of glucagon was confirmed after intratracheal administration of the glucagon dry powder to anesthetized rats, as evidenced by the increase in the blood glucagon and blood sugar levels. These results suggested the usefulness of an erythritol-based powder form of glucagon for systemic administration.

[Assumption of the area supplying Okayama Prefecture with Cryptomeria japonica and Cupressaceae airborne pollen, and of their scattering routes]

It is very important to predict and disseminate information about the total pollen counts of both Cryptomeria japonica and Cupressaceae for patients with pollinosis. In Okayama Prefecture, we have reported that the pollen counts of both Cryptomeria japonica and Cupressaceae are influenced by the meteorological conditions in the previous July. We predicted the area supplying Okayama Prefecture with Cryptomeria japonica and Cupressaceae pollen, and also the route of airborne pollen from the meteorological conditions and a topographical map of Okayama and four neighboring prefectures. It was found that Cryptomeria japonica and Cupressaceae pollen counts at the four observation sites correlated very well with the meteorological conditions at Tsuyama weather station in Okayama prefecture. Therefore, we considered that the areas supplying Okayama prefecture with Cryptomeria japonica and Cupressaceae pollen were the central northern areas including Tsuyama, 85.7% of whose plantation areas contained Cryptomeria japonica and Chamaecyparis obtusa, and that their pollen was carried along the routes of three major rivers, R. Takahashi, R. Asahi and R. Yoshii.

[Epidemiological survey on orchard pollinosis]

OBJECTIVE

To investigate the prevalence of Orchard Pollinosis in China.

METHOD

From 1995 to 1998, an epidemiological survey on orchard pollinosis was carried on among 1,660 primary and middle school students and 2,167 university students, including questionnaire investigation, nasal inspection and scratch test. From April to June of 1998, a clinical investigation of orchard pollinosis was adopted among 30 patients of allergic rhinitis including scratch test and nasal mucosa test.

RESULT

1. The total positive rate of orchard pollen scratch test was 6.7%, and the prevalence of orchard pollinosis was 0.37%. 2. 5 cases (16.7%) were hypersensitive to orchard pollen clinically in allergen test.

CONCLUSION

Orchard pollinosis is one kind of important pollinosis and should be paid high attention to.

Temporal variations in isolation frequency of endophytic fungi of Japanese beech

To determine the dominant fungal endophytes of the Japanese beech (Fagus crenata Blume) and to monitor their isolation frequency, we isolated fungi from symptomless organs of beech including leaves, petioles, and current and old (1- to 5-year-old) twigs after surface sterilization. Of the 13 fungal taxa obtained, 3 were isolated most often. An unidentified species of Discula and an unidentified sterile fungus, Lb, were isolated frequently from leaves, and an unidentified species of Phomopsis was isolated most frequently from twigs. The isolation frequency over the growing season varied for the two dominant fungal species in the leaves, Discula sp. and Lb. These two species had similar patterns of isolation, even in petioles and current-year twigs, although isolation frequencies of a given species varied with organs. An organ-specific distribution of the fungal species in the host plant was apparent. The three fungal species noted above were considered to be the dominant endophytes of the Japanese beech.Key words: fungal endophyte, Fagus crenata, isolation frequency, organ specificity.

[Prevalence rate of allergy to Japanese cedar pollen in Tokyo--from field investigation in 1996 by Tokyo Japanese Cedar Pollen Allergy Measurements and Review Committee]

Prevalence rate of allergy to Japanese cedar pollen was investigated by means of questionnaires and immunological examinations in residents of 3 regions in Tokyo (Akiruno city, Chofu city, and Ota ward). The results were as follows: 1) the prevalence rate of allergy to Japanese cedar pollen in Tokyo was 25.7% in Akiruno city, 21.1% in Chofu city, and 17.7% in Ota ward in 1996; 2) stratification by the age reveal that the prevalence rate was the highest in the age group of 30 to 44, and the group showed prevalence rate of above 40% in Akiruno city; 3) overall prevalence rate of Tokyo was 19.4% in 1996, which was approximately twice as much as that in 1985; 4) increase in prevalence rate in the recent decade was most significant in Akiruno city where the largest number of Japanese cedar pollen was detected in the air, and prevalence rate tended to rise in the young group of 14 or less.

[Forecast of the beginning day of Japanese cedar pollen release using variation pattern in air temperature]

It is important to forecast the beginning day of Japanese cedar pollen release for taking the preventive medical measure. We analyzed the relation between the beginning day of pollen release and the changing pattern of daily air temperature. A simple and practical method for forecasting the beginning day of pollen release is suggested. Polynomial of degree three was applied to represent the general variation pattern of air temperature. Multiple correlation coefficients between parameters of the polynomial and the beginning days of pollen release were 0.88 for the difference by year, and 0.81 for the difference by place. It was shown that the minimum value and the date of the fitted polynomial curve were related closely to the difference in the beginning day of pollen release by year. The minimum value and the date of the original series of air temperature showed high correlation with the difference in the beginning day of pollen release by place. We propose to use the minimum value and the date of original series and fitted curve of air temperature for forecasting the beginning day of cedar pollen release.

Yearly and seasonal changes of specific IgE to japanese cedar pollen in a young population

BACKGROUND

There have been no detailed long-term observations of the relationship between specific IgE production and stimulation by various naturally occurring allergens.

OBJECTIVE

This study was conducted to elucidate the yearly and seasonal changes of specific IgE antibody production to Japanese cedar pollen, an allergen of Japanese cedar pollinosis, in young adults.

METHODS

The number of Japanese cedar pollen were counted over a period of 9 years. Changes in the percentages of antibody carriers to Japanese cedar pollen and mite were examined during these years. Changes in Japanese cedar pollen-specific IgE levels between a low exposure year and a high exposure year in individual subjects were also investigated.

RESULTS

From 1987 to 1995, the percentages of Japanese cedar pollen-IgE carriers varied from about 30% to 50% with the intensity of pollen stimulation, and carriers tended to increase yearly. The rates of anti-mite IgE carriers changed little. In the spring which is the pollen season, Japanese cedar pollen-IgE levels in low exposure years were weaker than those in high exposure years in individual subjects. Levels in autumn, which is not the pollen season, showed equivalent levels in both high and low exposure years. Anti-mite IgE levels in individual subjects varied little during these years.

CONCLUSIONS

A long-term follow-up study supported that Japanese cedar pollen-IgE production is mainly associated with the degree of allergen exposure.

Allergic conjunctivitis caused by sugi (Cryptomeria japonica D. Don) pollen out of season

Allergic conjunctivitis caused by sugi pollen is considered to be strictly a "spring disease". However, a recent report indicated that sugi pollen is scattered not only in spring but in all seasons, especially in the autumn. We retrospectively determined the number of patients with allergic conjunctivitis caused by sugi pollen during each month for 3 consecutive years, and also investigated the growth of sugi male cones in November for four years. Diagnosis of allergic conjunctivitis was based on symptomatic complaints, clinical findings, and serum sugi pollen specific IgE measured by the Multiple Antigen Simultaneous Test 16. The annual incidence of allergic conjunctivitis peaked twice, once in spring and again in autumn. Scattering of sugi pollen occurred mostly in March and October, whilst the growth of sugi male cones was highest in November. Thus, allergy to sugi pollen can cause allergic conjunctivitis both in the spring and late autumn.

Change in the northward movement of the pollen front of Cryptomeria japonica in Japan, during 1986-1991

A map of pollen fronts of Cryptomeria japonica was compiled from pollen counts taken at 28 airborne sampling sites in Japan in 1986. Thereafter, the number of sites was increased, reaching 80 in 1991. In this way an accurate and complete map of the C. japonica pollen fronts was compiled annually. We used the results obtained from mapping the pollen fronts to draw up a map of the average locations of the front, from which the beginning of the pollen season can be predicted. A close correlation was found between the latitude of the airborne sampling sites and the mean interval between January 1 and the day pollen release began during these 6 years.

Pollen morphology of Ginkgo biloba and Cycas revoluta

Morphological studies on pollen grains of Ginkgo biloba L. and Cycas revoluta Thunb. were carried out by scanning electron microscopy. The pollen grains of both species are generally oblong with 1-sulcate apertures which are shrunken as a result of dryness. However, the swollen grains show an almost spherical form with a large and rounded germinal aperture. This aperture may not correspond to any aperture type so far known, although the term "anaporate" can be fitted to the swollen pollen grains. Auricular projections, which may be derived from protrusions of the ectosexine, can be seen sometimes on the surface of the pollen grains. These projections remind us of degraded versions of the bladders that may have been present on the pollen grains of the fossil ancestor. The inner side of the exine, which can be seen in thin sections obtained with the freezing microtome, is ornamented with reticulumlike sculptures. These endosculptures may be the first reported among gymnosperm pollen grains.

Increased papilla formation, a major factor of induced resistance in the barley – Erysiphe graminis f.sp. hordei system

Using two barley cultivars, 'Hanna' and 'Russian No. 12', resistance to Erysiphe graminis DC. f.sp. hordei Em. Marchal induced by preliminary inoculation with a compatible or an incompatible race of the powdery mildew fungus was examined with respect to cellular responses. When the primary leaves of barley seedlings were preliminarily inoculated with a compatible or an incompatible race on the abaxial leaf surface, they became resistant to the disease caused by challenge inoculation with the same pathogen on the adaxial surface. The resistance induced was expressed as decrease of fungal penetration and restriction of hyphal growth. These phenomena seemed to be attributable to the increase of papillae or papillalike structures which do not seem to be responsible for the race-specific resistance. On the basis of these results, it is suggested that the resistance induced may be different from race-specific resistance.