Suppression of rice blast,cabbage black leaf spot,and tomato bacterial wilt diseases by Meyerozyma guilliermondii TA-2 and the nature of protection

This study was conducted to evaluate the efficacy of yeast strain TA-2 for controlling rice blast, cabbage black leaf spot, and tomato bacterial wilt diseases. Microscopic and phylogenetic analyses based on rDNA-internal transcribed region (ITS) and rDNA-D1/D2 sequences indicated that yeast strain TA-2 is Meyerozyma guilliermondii. Pretreatment with TA-2 by soil drenching significantly reduced the severity of black leaf spot disease caused by Alternaria brassicicola and leaf blast disease caused by Magnaporthe oryzae. Symptom development of tomato bacterial wilt caused by Ralstonia solanacearum in both soil drench and needle inoculation tests was significantly reduced in TA-2-pretreated plants under soil drenching. Disease severity and R. solanacearum growth were significantly reduced in tomato plants pretreated with yeast culture, cell suspension, or culture filtrate of TA-2 under soil drenching. TA-2 does not produce antibiotics. The present study indicates that disease suppression is systemic, as the roots were treated with TA-2 and the pathogens were inoculated onto leaves or stems, thereby separating the two spatially. M. guilliermondii TA-2 could become a promising natural antimicrobial agent against rice blast, cabbage black leaf spot, and tomato bacterial wilt diseases and might be useful as an eco-friendly control measure, contributing to sustainable agriculture.     

Acibenzolar-S-methyl efficacy against bacterial brown stripe caused by Acidovorax avenae subsp. avenae in creeping bentgrass

Journal of General Plant Pathology - Bacterial brown stripe caused by Acidovorax avenae subsp. avenae (Aaa) causes serious damage on creeping bentgrass on golf course greens. However, there are few...     

Characterisation of novel simple sequence repeat (SSR) markers for melon (Cucumis melo L.) and their use for genotype identification

Summary

The objectives of this study were to provide a set of useful simple sequence repeat (SSR) markers, to characterise them, and to demonstrate their ability to detect polymorphisms across diverse genotypes of melon. A total of 183 SSR markers were developed in melon from libraries enriched for (CA)_n, (CT)_n, (AAG)_n, and (ATG)_n repeats. The efficiency of marker development was highest in the CT library. The efficiencies of the CA, AAG, and ATG libraries were similar, and approx. 60% of that of the CT library. Dinucleotide motifs were observed more frequently than trinucleotide motifs. Approx. 50% of CA/TG motifs and approx. 30% of CT/AG motifs exhibited a repeat number greater than ten, while most other motifs showed a repeat number of less than ten. Fifty primer pairs were selected at random and used to evaluate polymorphisms among 19 melon accessions representing seven varieties. All 50 markers were amplified successfully in the majority of accessions, and 42 markers were polymorphic among the 19 melon accessions. All polymorphic markers could detect variation between at least two accessions belonging to the same variety, with polymorphic information content values ranging from 0.10 - 0.96. The SSR markers developed were variable and transferable and will be valuable molecular tools in melon breeding programmes.     

Evaluating the Contribution of Long-Range Transport of Heavy Metals from the Asian Continent to Their Concentrations in Sediment Cores from Lake Shinji,Western Japan

The historical trend of heavy metal pollution recorded in sediment cores from Lake Shinji, western Japan, was investigated to evaluate the contribution of increasing long-range transport of heavy metals from the Asian continent in recent years. The concentrations of Cd, Co, Cr, Cu, Ni, Pb, Sb, and Zn and lead isotope ratios were determined for sediment cores collected at two sites in the lake. Among the metals, Cd, Sb, and Zn showed markedly high concentrations since the 1970s. Moreover, a high Pb concentration and less radiogenic lead isotope ratios have been observed since the 1980s in the core from a site close to the mouth of a major river. Air masses from the Asian continent, including China, Russia, and South Korea, have less radiogenic lead isotope ratios than those from Japan. This suggests that the recent increase in Pb concentration in the sediment core is primarily due to the long-range transport of heavy metals from the Asian continent, followed by their deposition in the catchment area of the river. The concentration ratios of Pb/Cd, Pb/Sb, and Pb/Zn of the sediment around 2000 were calculated on the basis of the metal concentrations in excess of those before 1940. They were then compared with the volume-weighted annual average concentration ratios of Pb/Cd, Pb/Sb, and Pb/Zn of rain samples collected on the shore of the lake for 1999–2001. The result showed that the ratios of the former to the latter are 1.0 for Cd, 0.69 for Sb, and 0.31 for Zn. Thus, it is likely that the long-range transport of Cd and Sb from the Asian continent also contributes significantly to the recent increase in the concentrations of these metals in the sediment core from Lake Shinji. For Zn, however, the contribution from the Asian continent was evaluated to be small, suggesting the importance of local sources such as effluent discharges.     

Genetic analysis of ion-beam induced extremely late heading mutants in rice

Two extremely late heading mutants were induced by ion beam irradiation in rice cultivar ‘Taichung 65’: KGM26 and KGM27. The F₂ populations from the cross between the two mutants and Taichung 65 showed clear 3 early: 1 late segregation, suggesting control of late heading by a recessive gene. The genes identified in KGM26 and KGM27 were respectively designated as FLT1 and FLT2. The two genes were mapped using the crosses between the two mutants and an Indica cultivar ‘Kasalath’. FLT1 was located on the distal end of the short arm of chromosome 8. FLT2 was located around the centromere of chromosome 9. FLT1 might share the same locus as EHD3 because their chromosomal location is overlapping. FLT2 is inferred to be a new gene because no gene with a comparable effect to that of this gene was mapped near the centromere of chromosome 9. In crosses with Kasalath, homozygotes of late heading mutant genes showed a large variation of days to heading, suggesting that other genes affected late heading mutant genes.     

Enzymatic saccharification and ethanol production of <Emphasis Type="Italic">Acacia mangium</Emphasis> and <Emphasis Type="Italic">Paraserianthes falcataria</Emphasis> wood,and <Emphasis Type="Italic">Elaeis guineensis</Emphasis> trunk

We examined the saccharification and fermentation of meals from Acacia mangium wood, Paraserianthes falcataria wood, and Elaeis guineensis trunk. The levels of enzymatic hydrolysis of cellulose and ethanol production were highest for P. falcataria wood and lowest for A. mangium wood. Ultrasonication pretreatment of meal further increased the rates of hydrolysis and ethanol production in meal from P. falcataria wood. Through this pretreatment, hemicelluloses (xylan and xyloglucan) and cellulose were released in the meal from P. falcataria wood. Loosening of hemicellulose associations can be expected to make P. falcataria wood more useful for bioethanol production.     

Study of mechanical properties of wooden bolt-nut connector I: effect of size and shape of thread on withdrawal strength

The withdrawal strength of a bolt-nut connector made from wood-based material was evaluated. The thread strength of the wooden bolt-nut connector was tested to select various parameters of the connector and the type of wood material; the wood materials tested were hard maple, white oak, ebony, glue-laminated bamboo, and densified Japanese cedar. A plane model of wooden threads with various thread angles was also evaluated. The results showed that the maximum failure load of the thread increased with increasing bolt density and connection area, which was calculated from the diameter of the bolt and the thickness of the nut. The withdrawal resistance after reaching the maximum load underwent a graded decrease because the bolt threads were broken one by one. In addition, the thread strength depended on the thread angle. In the model with a thread angle of 90°, compressive deformation in the transverse direction occurred prior to shear deformation along the root of the threads; the model with this thread angle thus had higher strength than those with other angles.     

茶叶β-葡萄糖苷酶亲和层析纯化与性质研究

以化学合成的β-葡萄糖苷酶的抑制剂β-葡萄糖脒为配体,通过N-糖苷键交联到支持物上,使糖脒N-糖苷键一侧的氨基保持带正电荷的活化状态,合成了一种β-葡萄糖苷酶的亲和层析树脂。这种合成的亲和层析树脂在弱酸条件下非常稳定,能选择性地吸附β-葡萄糖苷酶,并能多次重复使用。利用这种亲和层析树脂,在pH6和pH5条件下,从薮北种茶树叶片中纯化出两种分子量分别为63和75kDa的β-葡萄糖苷酶单体酶。以对硝基苯酚β-葡萄糖苷为底物,研究了两种酶的性质。TLC分析结果表明,这两种β-葡萄糖苷酶都能水解(Z)-3-己烯醇、苯甲醇和苯乙腈的β-D-葡萄糖苷。     

Evaluating Relative Contribution of Atmospheric Mercury Species to Mercury Dry Deposition in Japan

In this study, we evaluated the relative contribution of atmospheric particulate mercury (Hg(p)) and divalent reactive gaseous mercury (RGM) to mercury dry deposition in Japan. The dry deposition fluxes (on a water surface sampler) and atmospheric PM concentrations of Hg, Cd, Cu, Mn, Ni, Pb and V, which were measured concurrently from April 2004 to March 2006 at 10 sites across the nation, were used in this evaluation. We considered that Hg(p) and RGM, but not Hg⁰, are deposited on the water surface, and that our method of sampling Hg(p) without the use of KCl-coated annular denuders enables the exclusion of a significant amount of RGM artifact. The monthly average dry deposition velocities (= deposition flux/atmospheric PM concentration) of Cd and Pb were found to be similar to each other (Cd/Pb deposition velocities?=?1.06?±?0.58). It was assumed that the deposition velocity of Hg(p) is identical to the mean deposition velocity of Cd and Pb, because the particle size distribution of Hg(p) is likely similar to those of both elements. Using this deposition velocity, the monthly dry deposition flux of Hg(p) was calculated. The average contribution (±1σ) of Hg(p) to the annual deposition flux at ten sites was 26?±?15%. The mercury dry deposition flux increased generally from spring to early summer, which was attributed mostly to the deposition of RGM. This seasonal change correlated to that in photochemical oxidant (primarily O₃) concentration in air at most sites. These suggest that mercury dry deposition in Japan is predominantly deposition of RGM, which was formed via oxidation of Hg⁰ by O₃ in the atmosphere.