Microsatellite Analysis of Expressed Sequence Tags and Development of EST-SSR Markers for Melampsora spp.

In this study,64 498 ESTs of Melampsoraspp.was assembled into 1 998 contigs,and 604SSR loci were detected on these contigs,with 736.6 bp containing one SSR on average.Among these SSRs,trinucleotide repeats were the most abundant repeats(44.70%).As for the composition of microsatellites, AC and AT repeats were the richest motif in dinucleotide repeats,and AGT and AAG repeats were the most frequent motifs in trinucleotide repeats,whereas(AAAN) n and(AAAAN) n repeats were dominant in tetranucleotide and pentanucleotide repeats,respectively.All the dominant repeat motifs of different types of SSRs were rich in A and T.In EST sequences of Melampsoraspp.genome,microsatellites longer than 20 bp accounted for about 15.07%.It was noticeable that microsatellites were highly rich in the expressed sequences of Melampsoraspp.genome,which implied that SSRs played a significant role in triggering the gene mutation in Melampsoraspp.genome.A total of 455 SSR primers were designed according to the detected microsatellites using Primer 5.0 and Oligo 6. 0,and 30 primer pairs were randomly selected for amplification test.Among these primer pairs,27 primer pairs succeed in amplification,with a successful rate of 90%.Eight primer pairs generated polymorphic fingerprints in Melampsoraspp.collected from different poplar genotypes,accounting for 26.7% of the total primer pairs.The EST-SSR markers developed fromMelampsoraspp.EST sequences provided important marker resources for studying Melampsoraspp.from the aspects of pathogen identification and survey of genetic variation.

Nine new species of the spider genus Stedocys (Araneae, Scytodidae) from China and Thailand

Nine new species of the genus Stedocys Ono, 1995 are described: Stedocys gaolingensis Wu & Li sp. n.(♂♀, Guangxi), S. huangniuensis Wu & Li sp. n.(♀, Guangxi), S. ludiyanensis Wu & Li sp. n.(♂♀, Guangxi), S. matuoensis Wu & Li sp. n.(♀, Guangxi), S. pulianensis Wu & Li sp. n.(♂, Guangxi), S. shilinensis Wu & Li sp. n.(♂♀, Hainan), S. xianrenensis Wu & Li sp. n.(♂♀, Guangxi), S. xiangzhouensis Wu & Li sp. n.(♂♀, Guangxi) from China, and S. zhaoi Wu & Li sp. nov.(♂♀, Kanchanaburi) from Thailand. Diagnoses of nine new species are provided. DNA barcodes for six new species are documented for future use and as proof of molecular differences between these species.

Molecular Cloning and Characterization of Citrate Synthase Gene in Rice(Oryza sativa)

The full-length OsCS encoding citrate synthase was isolated from rice (Oryza sativa L. subsp. japonica). OsCS is 1477-bp long and encodes a 474 amino acid polypeptide. Its putative protein sequence is highly identical to Daucus carota, Nicotiana tabacum, Beta vulgaris subsp., Arabidopsis thaliana, and Citrus junos (>70%). The deduced amino-terminal sequence of OsCS showes characteristics of mitochondrial targeting signal. Southern blot analysis using ORF of the OsCS as the probe indicated that this gene exists in multiple copies in rice genome. The band with predicated size of 82 kD was detected by Western blot after being induced by 0.4 mmol/L IPTG.

Structural Analysis of Water-soluble Polysaccharide PIP_1 Extracted from the Cultured Mycelium of Phellinus igniarius

Water-soluble crude polysaccharide（PIP） was extracted from cultured mycelium of the fungus Phellinus igniarius. After ethanol precipitation and sepharose CL-6B gel filtration, the fraction of PIP1 was obtained, which was shown to be a homogeneous polysaccharide by means of high-performance liquid chromatography. The structure of PIP1 was determined by using several methods. GC analysis indicates that PIP1 is composed of the monosaccharides of glucose, galactose, and mannose. Their molar ratio is 3.70∶4.06∶1.00. The molar weight was estimated to be 17 kd via HPLC. IR, GC, partial hydrolysis with acid, periodate oxidation, Smith degradation, methylation, and GC-MS analysis were used for the structural analyses of PIP1. The results show that PIP1 has a small quantity of branch structure. The main glycosidic linkage of PIP1 has a β-configuration. The main chain is made up of a large mass of glucose（ 1→3 ） and few mannose（1→4）; the side chain is composed of glucose（1→3） and galactose（1→6）; the nonreduced end is composed of galactose and glucose. The side chains are branched at 6-O of glucose（1→3,6） and mannose（1→4,6）. On an average, there are three branches among 20 residues. It is presumable that the existence of 1,3-linked Glc in the main and side chains is the main reason for its higher antitumor activity.

High Temperature Modifies Resistance Performances of Rice Varieties to Brown Planthopper,Nilaparvata lugens(Stl)

To investigate the effect of temperature on the resistance characteristics of rice varieties with different resistance genes to brown planthopper(BPH),Nilaparvata lugens(Stl),the resistances of IR26(Bph1)and IR36(bph2)to BPH population in Hangzhou,China were monitored in greenhouse during September in 2007 and 2008 by using the standard seedling screening techniques(SSST)developed by the International Rice Research Institute(IRRI).Furthermore,the changes in resistance of IR26 and IR36 to BPH,soluble sugar and oxalic acid contents in 25-day-old rice plants of susceptible variety TN1 and resistant varieties IR26 and IR36 were detected at five temperatures(22℃,25℃,28℃,31℃ and 34℃).IR26 completely lost resistance both in greenhouse and at the five tested temperatures.IR36 still had moderate resistance at natural temperature,but its resistance decreased gradually when the temperature increased from 25℃ to 34℃,and fully lost its resistance at 31℃ and 34℃.The highest durable resistance of IR26 and IR36 were recorded at 25℃.The soluble sugar content in plants of the three tested rice varieties increased with temperature increase,and the oxalic acid content increased with the temperature increase at first,maximized at 25℃,and then declined.Two-way ANOVA indicated significant effects of temperature and rice variety on contents of soluble sugar and oxalic acid in rice plants.

Natural infectious behavior of the urediniospores of Melampsora larici-populina on poplar leaves

The uredinial stage in the life cycle of Melampsora larici-populina on poplar leaves is the most important pathogenic phase. We captured partial phases of uredinial infection in the wild, aiming to reconstruct the process of uredinial ontogeny by using scanning and transmission electron microscope. At the initial infection stage, germ tubes germinated from the echinulate urediniospores. Germ tubes were frequently seen to merge with the leaf surface and cuticle breakage was observed, indicating direct hyphal penetration. Stomata penetration occurred commonly, sometimes with more than one germ tube penetrating the same stoma. Melampsora larici-populina did not form appressoria in the infection process,implying that infectious behavior of this pathogen may differ from the other rust pathogens. In general, germ tubes branched randomly, and no distinct evidence indicated that stoma could induce or orient germ tube branches. However, oriented germ tube growth has been occasionally observed in other studies. The urediniospores collapsed and finally wizened when they became nutrient stressed. At the last stage of infection, the uredinia erupted from the leaf epidermis and appeared as orange pustules on the leaf surface.

Estimation of aboveground biomass using in situ hyperspectral measurements in five major grassland ecosystems on the Tibetan Plateau

Aims There are numerous grassland ecosystem types on the Tibetan Plateau.These include the alpine meadow and steppe and degraded alpine meadow and steppe.This study aimed at developing a method to estimate aboveground biomass(AGB)for these grasslands from hyperspectral data and to explore the feasibility of applying air/satellite-borne remote sensing techniques to AGB estimation at larger scales.Methods We carried out a field survey to collect hyperspectral reflectance and AGB for five major grassland ecosystems on the Tibetan Plateau and calculated seven narrow-band vegetation indices and the vegetation index based on universal pattern decomposition(VIUPD)from the spectra to estimate AGB.First,we investigated correlations between AGB and each of these vegetation indices to identify the best estimator of AGB for each ecosystem type.Next,we estimated AGB for the five pooled ecosystem types by developing models containing dummy variables.At last,we compared the predictions of simple regression models and the models containing dummy variables to seek an ecosystem type-independent model to improve prediction of AGB for these various grassland ecosystems from hyperspectral measurements.Important findings When we considered each ecosystem type separately,all eight vegetation indices provided good estimates of AGB,with the best predictor of AGB varying among different ecosystems.When AGB of all the five ecosystems was estimated together using a simple linear model,VIUPD showed the lowest prediction error among the eight vegetation indices.The regression models containing dummy variables predicted AGB with higher accuracy than the simple models,which could be attributed to the dummy variables accounting for the effects of ecosystem type on the relationship between AGB and vegetation index(VI).These results suggest that VIUPD is the best predictor of AGB among simple regression models.Moreover,both VIUPD and the soil-adjusted VI could provide accurate estimates of AGB with dummy variables integrated in regression models.Therefore,ground-based hyperspectral measurements are useful for estimating AGB,which indicates the potential of applying satellite/airborne remote sensing techniques to AGB estimation of these grasslands on the Tibetan Plateau.