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A total of 651 isolates of cucumber corynespora leaf spot fungus ( Corynespora cassiicola ) collected from cucumber in Japan, either with (438 isolates) or without (213 isolates) a prior history of boscalid use, were tested for their sensitivity to boscalid by using a mycelial growth inhibition method on YBA agar medium. Additionally, seven isolates of C. cassiicola obtained from tomato, soybean, eggplant (aubergine) and cowpea in different locations in Japan were tested before boscalid registration. Minimum inhibitory concentration (MIC) and 50% effective concentration (EC50 ) values for 220 isolates from crops without a prior history of boscalid use ranged from 0·5 to 7·5 μg mL−1 and from 0·04 to 0·59 μg mL−1 , respectively. Two hundred and fourteen out of 438 isolates collected from ten cucumber greenhouses in Ibaraki Prefecture, Japan, which received boscalid spray applications showed boscalid resistance, with MIC values higher than 30 μg mL−1 . Moreover, resistant isolates were divided into two groups: a moderately resistant (MR) group consisting of 189 isolates with EC50 values ranging from 1·1 to 6·3 μg mL−1 , and a very highly resistant (VHR) group consisting of 25 isolates with EC50 values higher than 24·8 μg mL−1 . MR isolates were detected from all ten greenhouses, but VHR isolates were detected from only three. As a result of fungus inoculation tests which used potted cucumber plants, control failures of boscalid were observed against resistant isolates. Efficacy of boscalid was remarkably low against VHR isolates in particular. This is the first known report on boscalid resistance in Japan. 相似文献
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Seko Takuya Imamura Shintaro Ishihara Kenji Yamashita Yumiko Yamashita Michiaki 《Fisheries Science》2020,86(1):171-179
Fisheries Science - The novel organic selenium compound, selenoneine, is found in the blood of tuna and has metal-binding activity. In this report, selenoneine displays tyrosinase inhibitory... 相似文献
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Y. Seko A. Bolay L. Kiss V. Heluta B. Grigaliunaite S. Takamatsu 《Plant pathology》2008,57(2):243-250
A preliminary analysis demonstrated that the powdery mildew fungus infecting Syringa spp. (lilacs) in different parts of the world is divided into two groups (S-type and K-type) based on the nucleotide sequences of the rDNA ITS regions. In spite of the marked genetic differences (only c . 94% similarity between ITS types), fungi belonging to these two ITS groups are difficult to distinguish based on morphological characteristics. To determine their geographical distribution, ITS haplotypes were determined for a total of 139 powdery mildew specimens collected in Asia, Europe and North and South America between 1977 and 2005. Curiously, until 1990, only the S-type was found in Europe, whilst the K-type prevailed in East Asia. The first European specimen belonging to the K-type was collected in Ukraine in 1991. Other European K-type samples were collected in Lithuania and Switzerland in 2000, and in other countries after 2002. The incidence of the S-type decreased rapidly in Europe after the 1990s. This result strongly suggests that the K-type was introduced to Europe from East Asia in the 1990s and expanded from Eastern Europe westward, replacing the S-type present on the European lilacs. The K-type produces abundant chasmothecia (sexual fruiting bodies), whereas chasmothecia on the S-type are rare in Europe and East Asia. It is likely that the recent abundant production of chasmothecia on Syringa spp. in Central Europe is explained by the migration of the K-type to Europe. 相似文献
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Seko Takuya Imamura Shintaro Ishihara Kenji Yamashita Yumiko Yamashita Michiaki 《Fisheries Science》2019,85(4):731-736
Fisheries Science - Selenoneine is a selenium-containing compound that exhibits strong radical-scavenging activity. Here we present a novel function of selenium in which selenoneine exhibits... 相似文献
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Allozyme polymorphism at seven loci (TPI, G6PD-2,IDH-1, SKD-2, MDH-1, GOT-1, andGOT-2) was employed to detect the level of geneticdiversity in C.alismatifolia populations from both cultivatedand wild habitats in Thailand. High diversity was observed in allpopulations with relatively lower values in cultivated populations.Percentage of polymorphic loci (P)varied from 85.7–100% in cultivated populations comparedwith 100% in all natural populations. Allele number per locus(A
L) was 3.14 in cultivatedpopulations, and from 2.86–4 in natural populations. Allelenumber per polymorphic locus(A
P) of cultivated andnatural populations ranged from 3.14–3.5 and 2.86–4,respectively. Genetic diversity within populations(H
S) varied from0.586–0.611 in cultivated and from 0.621–0.653 in naturalpopulations. The genetic identity(I
SP) for the species was0.833. The cultivated populations yielded higher value of geneticidentity with highland populations(I
C
/H
=0.776) than with the lowland ones(I
C
/L
=0.754). The analysis of genetic similarities with theNeighbor-Joining algorithm results in the separation ofcultivated populations from all wild populations. One highlandpopulation from the tourist spot, H2, was placed in a separatecluster between the cultivated and other wild populations. It isconsidered as the possible origin of the cultivatedpopulations. 相似文献
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Summary Wheat breeding efforts for a half century in Japan were investigated by using of 129 varieties registered in MAFF from 1929 to 1984 in the view point of case history for three years. Varieties released in each breeding station are classified apparently by growth habit associated closely with duration of the cold requirement. Heading date is earlier in varieties released in southwest breeding stations (southern varieties) than in varieties released in northern breeding stations (northern varieties). Culm length is higher and the pre-harvest sprouting is more sensitive in northern varieties. In quality characters, northern varieties has the higher milling rate, lower apparent amylose content and larger particle size of flour. In varieties released in the Tohoku district, trend of breeding direction with time is smaller ear numbers and larger 1,000-grain weight and greater resistance to powdery mildew. In varieties released in the Kyushu district, a significant correlation with released year was clearly observed with regard to early maturity, short culm length, less grain crude protein content, less apparent amylose content and higher milling rate on breeding advancement. 相似文献
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Distribution and molecular characterization of Corynespora cassiicola isolates resistant to boscalid
T. Miyamoto H. Ishii G. Stammler A. Koch T. Ogawara Y. Tomita J. M. Fountaine S. Ushio T. Seko S. Kobori 《Plant pathology》2010,59(5):873-881
A total of 618 isolates of corynespora leaf spot fungus (Corynespora cassiicola) collected from 24 commercial cucumber greenhouses in 12 cities in Ibaraki Prefecture, Japan, were tested for their sensitivity to boscalid. Boscalid‐resistant isolates were detected in 17 out of 19 greenhouses with a history of use of this fungicide and detection frequencies of the resistant isolates exceeded 47% in nine greenhouses. Frequencies of very highly resistant (VHR) isolates with 50% effective concentration (EC50) values of boscalid exceeding 30 μg mL?1 were higher than those of moderately resistant (MR) isolates with EC50 ranging from 2·0 to 5·9 μg mL?1 in 11 greenhouses. Additionally, highly resistant (HR) isolates with EC50 from 8·9 to 10·7 μg mL?1 were first detected. Furthermore, molecular characterization of genes encoding succinate dehydrogenase (SDH) subunits (SdhA, SdhB, SdhC and SdhD) was carried out to elucidate the amino acid substitution responsible for the resistance to boscalid. All 23 VHR isolates had the same mutation from CAC to TAC in the SdhB gene leading to the substitution of histidine with tyrosine at amino acid position 278 (B‐H278Y). At the same position, the substitution to arginine conferred by a mutation to CGC (B‐H278R) was detected in all four HR isolates. Some MR isolates showed a substitution from serine to proline at position 73 in SdhC (C‐S73P), from serine to proline or from glycine to valine at position 89 (D‐S89P) and 109 (D‐G109V), respectively, in SdhD. There was no common mutation in SDH genes of all MR isolates. 相似文献
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