Improvement of Resistance to Rice Blast in Zhenshan 97 by Molecular Marker-aided Selection

Fungi blast is one of the most serious diseases of rice worldwide. Breeding resistant varieties have been proved to be the most effective and economical means to control the disease. This paper describes the molecular marker-assisted selection (MAS) procedure for a broad-spectrum blast resistant gene Pi1 integrated into an elite hybrid maintainer line, Zhenshan 97. A simple sequence repeat (SSR) based on molecular marker-aided selection system for Pi1 segment was established. Using a backcross population and a blast isolate F1829, Pi1 gene was mapped on the top of chromosome 11 between markers RZ536 and RM144, with a distance of 9.7 cM and 6.8 cM, respectively. Seventeen families derived from the recurrent parent Zhenshan 97 were obtained with homozygous Pi1 gene. The background of the 17 families was identified with inter simple sequence repeat (ISSR) amplification, the highest recovery of the Zhenshan 97 genetic background was 97.01% after the assay of 167 polymorphic bands.

Primary Study of Rice AFLP Analysis Optimization of Reaction Conditions and Analysis of Thermo sensitive Genic Male Sterile Rice Allelic Mutant Lines

AFLP analysis was performed between a pair of thermo_sensitive genic male sterile (TGMS) rice allelic mutant lines (5460S and 5460F). The reaction conditions for rice AFLP assay were optimized. The relative efficiencies for polymorphism detection of RFLP, RAPD and AFLP were compared. The results indicated that the efficiency for polymorphism detection in rice was in the order of AFLP>RAPD>RFLP, and also indicated that AFLP was a powerful DNA molecular marker technique for polymorphism detection, especially in the case of extremely low polymorphism, such as isogenic lines and allelic mutant lines. Some of the AFLP products between the TGMS rice allelic mutant lines were cloned. Three of them were used as mixed probes to screen BAC library of rice line 5460S. 12 positive clones were screened out. In addition, the advantages and disadvantages of these three molecular marker systems were discussed.

Mapping of S-b Locus for F_1 Pollen Sterility in Cultivated Rice Using PCR Based Markers

In cultivated rice ( Oryza sativa L.), F-1 pollen sterility is controlled by at least 6 loci of the F, pollen sterility genes. To map S-b, one of loci, rice variety Taichung 65 (T65) carrying S-b(j)/S-b(j) and its near-isogenic line TIST2 carrying S-b(i)/S-b(i) were used to develop the mapping population. One hundred and fifty-eight microsatellite markers were selected to survey T65 and TISL2. RM13 on chromosome 5 was found to be polymorphic between them. Cosegregation indicated that RM13 was closely linked with locus S-b. Eleven RFLP markers were selected on the corresponding region from the genetic map of Rice Genome Research Program (RGP) of Japan to convert into sequence-tagged site (STS) markers. Amplicon length polymorphism (ALP) was carried out, but none of them was found to be polymorphic between T65 and TISL2. Then PCR-based RFLP (PBR) was done using six 4-nucleotide recognizing restriction endonucleases. Polymorphism was detected when PCR products of R830STS and R2213SSTS were digested with Taq I. Genetic analysis indicated that the distance between locus S-b and markers, R830STS, RM13 and R2213SSTS were 3.3 cM (centi-Morgan), 5.2 cM and 5.5 cM, respectively. These PCR-based markers could be directly used in marker-assisted selection. The technical system combining genetic mapping and PCR-based marker-assisted selection will facilitate the development of molecular breeding.

Comparative Physical Localization of Rice Pib Gene and Its Linked RFLP Markers in Oryza sativa, O. officinalis and Zea mays

Comparative genetic studies have shown that there are widespread synteny and colinearity of the genes among different species within grass family. Rice ( Oryza sativa L.) is a model plant, and analysis of its genome allows us to reveal the common features and the evolutionary rules of the gramineous genomes and accumulate the data for establishment of a common genetic system in the Poaceae. In this study, a rice gene Pib ( 10.3 kb), a map-based cloned gene, and RFLP markers linked with it are used as the tested probes to investigate their homology and physical location among the tested species. Southern blotting analysis showed that there were sequences homologous to Pib in maize genome. Further, Pib was localized onto the chromosomes of O. sativa ssp. indica cv. Guangluai 4, O. officinalis Wall ex Watt and the inbred line of Zea mays cv. Huangzao 4. The results of fluorescence in situ hybridization (FISH) and double-color FISH indicated that a synteny of Pib and RFLP markers linked with Pib existed among the genomes of the three tested species.

Segmental Duplications Are Common in Rice Genome

Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.

漫话“水则”

漫话“水则”水则足古代观测水位的标记、每市尺为“一侧”．又称为“一划”。竖立在渠道的关键部位，观测洪怕水位的变化．井用以测量水量．作为灌区农用灌溉配水”的依据、同时关系到防洪渡汛的安全。那么，水则是怎样来的呢？早在２０００多年前．都江堰建成后，就用石...

Research Progress on Mechanized Mixed Sowing Seed Production Technology of Hybrid Rice

Hybrid rice planting has been widely popularized and applied in the world. However, the high cost of seed production and the complicated procedures have become a bottleneck in the development of hybrid rice. The research progress on mixed sowing seed production techniques of hybrid rice was introduced from the aspects of rice resources creation, breeding, sowing seed technology research and cost benefit analysis. The production technology of the new mixed seeding combina- tion ＂Xinhunyou 6＂ was investigated, including the research and validation of benta- zon treatment period and dosage, mixing ratio of male and female parents, and the comparative test of different different sowing methods, which revealed that the mechanization technology of seed production of hybrid rice was mature and feasible and would be one of the most important development trend of technological devel- opment of hybrid rice production.

A Scheme of Fragile Watermarking Based on SVD and 2D Chaotic Mapping

This paper proposed a novel fragile watermarking scheme based on singular value decomposition (SVD) and 2D chaotic mapping. It obtains chaotic initial values from the image blocks singular value decomposition and the user’s key, then uses the chaotic mapping to get the chaotic sequence and inserts the sequence into the LSBs of the image blocks to get the watermarked image blocks. The paper reconstructed the watermarked image from all the embedded blocks. The analysis and experimental results show that the scheme is pretty fragile to tampering, and it can localize the tampering position accurately, reach 3×3 blocks.

A robust watermarking algorithm based on significant-tree in Contourlet domain

An adaptive algorithm operating in the Contourlet domain is presented. Contourlet is a new image sparse representation, which is better than a wavelet for piecewise smooth images with smooth contours. Because of flexible multiresolution, local and directional sensitivity of Contourlet transform, our approach also defines significant-tree in the Contourlet domain. By analyzing the relation of the Contourlet coefficients, we embed the watermarking into all the coefficients of each significant-tree. Then referring to the statistical properties of the coefficients, the masking characteristics of texture are defined for adaptively controlling the embedding strength. Experimental results show that the proposed algorithm is highly robust to various attacks, such as JPEG compression, medium filtering, cropping and rotation. Furthermore, comparisons with a classical method in the wavelet domain prove the validity of the new algorithm.

Genotype Analysis of Yuzhenxiang, a Long Grain, High Quality Aromatic Rice Cultivar

In China,the market share of a rice cultivar is mainly determined by its yield and quality.Yuzhenxiang is a high-quality variety with extra-slender grain shape,good quality and unique aroma.In order to investigate its genetic background,12 pairs of functional markers were used to detect the genotype distribution of eight major grain shape genes including GS3,GW5,GS6,GW6a,GL7/GW7,GLW7,GW8,GS9,one amylase gene Wx and one aroma gene BADH2 in Yuzhenxiang by using Nipponbare,9311,Huazhan,Zhonghui 8015 and Zhonghui 9308 as controls.The results indicated that the slender grain type of Yuzhenxiang was probably affected by GS3 and GL7/GW7 with the positive co-regulation of multiple grain shape genes,and its outstanding rice quality may be resulted from the cumulative effects of GLW7,GW8 and Wx genotypes,while its unique aroma may be mainly regulated by BADH2-E7 deletion.

Preoperative detection and localization of small bowel hemangioma: Two case reports

Among the various diagnostic modalities for small bowel hemangioma, video capsule endoscopy (VCE) and double-balloon enteroscopy (DBE) can be recommended as part of the work-up in patients with obscure gastrointestinal bleeding (OGIB). DBE is superior to VCE in the accuracy of diagnosis and therapeutic potential, while in most cases total enteroscopy cannot be achieved through only the antegrade or retrograde DBE procedures. As treatment for small bowel bleeding, especially spout bleeding, localization of the lesion for the decision of DBE insertion facilitates early treatment, such as endoscopic hemostatic clipping, allowing patients to avoid useless transfusion and the worsening of their disease into life-threatening status. Applying endoscopic India ink marking prior to laparoscopic surgical resection is a particularly useful technique for more minimally invasive treatment. We report two cases of small bowel hemangioma found in examinations for OGIB that were treated with combination of laparoscopic and endoscopic modalities.

Genetic Similarity Analysis of Hunan Rice Landraces with Same or Similar Name in Household and Genebank Conservations

This study was conducted to analyze the phenotypic and genotypic similarity or diversity of rice （Oryza sativa L.） landraces in household and hypothermic genebank conservations in Hunan Province and identify the genetic distance between the rice landraces with the same or similar names. A total of 92 accessions of rice landraces were divided into seven groups according to their local names, but the morphological traits showed large variations even within the same group as well as between household and genebank conservations. The SSR marker analysis showed that, in all the groups except Group E, the allelic variations within each subgroup of the household conservation were less than those of the genebank conservation, indicating the household-conserved rice landraces’ many-generation purifcation from natural and artifcial selections in the process of their cultivation year after year; and the similarity coeffcient among the household rice landraces was the highest except for Groups C and E. Thus, the study suggested that the same-name or similar-name rice resources retained by farmers would be valuable for collection and evaluation.

An Institutional Innovation for Agricultural Technology Adaptation and Adoption： Rice in West and Central Africa

This paper traces the origins and achievements of the R^seau Ouest et Centre Africain du Riz--ROCARIZ （West and Central Africa Rice Research and Development Network）. The ROCARIZ institutional arrangement showed that rice science is approached from multi-stakeholder perspectives that place end users and entrepreneurs at the center of research for development, and collaboration among rice-based stakeholders can be enhanced and sustained. The ROCARIZ used competitive research grants through multi-stakeholder task forces to generate, adapt, and facilitate the adoption of rice-based technologies and approaches by resource poor households. The grants contributed to： （1） farmer adoption of high yielding and multiple stress resilient lowland NERICAs （New Rices for Africa） （NERICA-L）; （2） producer access to credit and services resulting in increased marketing of quality seed rice, paddy, and grain rice by farmer entrepreneurs and poor rural households; （3） improved skills of stakeholders on the use of impact assessment tools to demonstrate adoption of rice-based technologies; （4） enhanced skills of rice breeders in molecular assisted marker selection to shorten the varietal development process; and （S） experiential learning and sharing to improve access to information and knowledge.

ISSR markers based on GA and AG repeats reveal genetic relationship among rice varieties tolerant to drought,flood,or salinity

Drought, flood, salinity, or a combination of these limits rice production. Several rice varieties are well known for their tolerance to specific abiotic stresses. We determined genetic relationship among 12 rice varieties including 9 tolerant to drought, flood, or salinity using inter-simple sequence repeat （ISSR） markers. Based on all markers, the nine tolerant varieties formed one cluster distinct from the cluster of three control varieties. The salt-tolerant varieties were closest to two flood-tolerant varieties, and together they were distinct from the drought-tolerant varieties. （GA）8YG was the most informative primer, showing the highest polymorphic information content （PIC） and resolving power （Rp）. The drought-, flood-, and salt-tolerant varieties grouped in three distinct clusters within the group of tolerant varieties, when （GA）8YG was used. Sabita was the only exception. The two aus varieties, Nagina22 and FR13A, were separated and grouped with the drought- and flood-tolerant varieties, respectively, hut they were together in dendrograms based on other primers. The results show that ISSR markers associated with （GA）sYG delineated the three groups of stress-tolerant varieties from each other and can be used to identify genes/new alleles associated with the three abiotic stresses in rice germplasm.

Identification of the novel recessive gene pi55(t) conferring resistance to Magnaporthe oryzae

The elite rice cultivar Yuejingsimiao 2 （YJ2） is characterized by a high level of grain quality and yield, and resistance against Magnaporthe oryzae. YJ2 showed 100% resistance to four fungal populations collected from Guangdong, Sichuan, Liaoning, and Heilongjiang Provinces, which is a higher frequency than that shown by the well-known resistance （R） gene donor culti- vats such as Sanhuangzhan 2 and 28zhan. Segregation analysis for resistance with F2 and F4 populations indicated the re- sistance of YJ2 was controlled by multiple genes that are dominant or recessive. The putative R genes of YJ2 were roughly tagged by SSR markers, located on chromosomes 2, 6, 8, and 12, in a hulked-segregant analysis using genome-wide selected SSR markers with F4 lines that segregated into 3 resistant （R）： 1 susceptible （S） or 1R：3S. The recessive R gene on chromosome 8 was further mapped to an interval ~1.9 cM/152 kb in length by linkage analysis with genomic position-ready markers in the mapping population derived from an F4 line that segregated into 1R：3S. Given that no major R gene was mapped to this inter- val, the novel R gene was designated as pi55（t）. Out of 26 candidate genes predicted in the region based on the reference genomic sequence of the cultivar Nipponbare, two genes that encode a leucine-rich repeat-containing protein and heavy-metalassociated domain-containing protein, respectively, were suggested as the most likely candidates for pi55（t）.

Label-free quantification of differentially expressed proteins in mouse liver cancer cells with high and low metastasis rates by a SWATH acquisition method

Label-free quantification is a valuable tool for the analysis of differentially expressed proteins identified by mass spectrometry methods.Herein,we used a new strategy:data-dependent acquisition mode identification combined with label-free quantification by SWATH acquisition mode,to study the differentially expressed proteins in mouse liver cancer metastasis cells.A total of 1528 protein groups were identified,among which 1159 protein groups were quantified and 249 protein groups were observed as differentially expressed proteins(86 proteins up-regulated and 163 down-regulated).This method provides a commendable solution for the identification and quantification of differentially expressed proteins in biological samples.

^(18)F-Labeling techniques for positron emission tomography

Much research effort has been made to understand various biological processes at levels of molecules using molecular imaging techniques. Because of great sensitivity, high resolution, and rapid detection, positron emission tomography （PET） imaging is becoming one of the most used imaging techniques for medical diagnose and pre-clinical studies. Here we provide a review on molecular imaging and PET imaging. An introduction is also provided on ~SF-fluorine labeling techniques for the preparation of PET imaging probes. A summary and comparison of currently available ~SF-fluorine labeling methods is provided. The per- spectives for 18F-fluorine labeling techniques are also given.

The role of soluble sugars during drought in tropical tree seedlings with contrasting tolerances

Aims Non-structural carbohydrates(NSCs)are plant storage compounds used for metabolism,transport,osmoregulation and regrowth following the loss of plant tissue.Even in conditions suitable for optimal growth,plants continue to store NSCs.This storage may be due to passive accumulation from sink-inhibited growth or active reserves that come at the expense of growth.The former pathway implies that NSCs may be a by-product of sink limitation,while the latter suggests a functional role of NSCs for use during poor conditions.Methods Using 13C pulse labelling,we traced the source of soluble sugars in stem and root organs during drought and everwet conditions for seedlings of two tropical tree species that differ in drought tolerance to estimate the relative allocation of NSCs stored prior to drought versus NSCs assimilated during drought.We monitored growth,stomatal conductance,stem water potential and NSC storage to assess a broad carbon response to drought.Important Findings We found that the drought-sensitive species had reduced growth,conserved NSC concentrations in leaf,stem and root organs and had a larger proportion of soluble sugars in stem and root organs that originated from pre-drought storage relative to seedlings in control conditions.In contrast,the drought-tolerant species maintained growth and stem and root NSC concentrations but had reduced leaf NSCs concentrations with a larger proportion of stem and root soluble sugars originated from freshly assimilated photosynthates relative to control seedlings.These results suggest the drought-sensitive species passively accumulated NSCs during water deficit due to growth inhibition,while the drought-tolerant species actively responded to water deficit by allocating NSCs to stem and root organs.These strategies seem correlated with baseline maximum growth rates,which supports previous research suggesting a trade-off between growth and drought tolerance while providing new evidence for the importance of plasticity in NSC allocation during drought.

An experimental investigation of tribological performance of triangular textures in water lubrication regime

Surface texturing has been considered as an effective approach to improve the tribological performances.Based on the consideration of enhancing the tribological performance,the experiments are carried out to investigate tribological performance of triangular textures in water lubrication.The textures are generated by the Nd:YAG laser marking system,with an area density of 20%and a depth of 7 m and are distributed uniformly on the surface of the SiC rings.Compared with the circular textures,the triangular textures have obvious tribological anisotropy.The triangular textures in clockwise direction show the best friction reduction effect among the three textures.The friction reduction mechanisms of the triangular textures in clockwise direction are also analyzed and discussed.

A novel method for identification and relative quantification of N-terminal peptides using metal-element-chelated tags coupled with mass spectrometry

By means of the reaction between a DOTA-NHS-ester bifunctional reagent and N-terminal peptides of proteins, and then che- lation of lanthanide metal ions as tags, we established a novel method for the identification of N-terminal peptides of proteins and their relative quantification using metal-element-chelated tags coupled with mass spectrometry. The experimental results indicate that metal elements are able to completely label N-terminal peptides at the protein level. The N-terminal peptides are enriched as the peptides digested with trypsin are selectively eliminated by isothiocyanate-coupled silica beads. We success- fully identified the N-terminal peptides of 158 proteins of Thermoanaerobacter tengcongensis incubated at 55 and 75 ℃, among which N-terminal peptides of 24 proteins are partially acetylated. Moreover, metal-element tags with high molecule weights make it convenient for N-terminal peptides consisting of less than 6 amino acids to be identified; these make up 55 percent of the identified proteins. Finally, we developed a general approach for the relative quantification of proteins based on N-terminal peptides. We adopted lysozyme and ribonuclease B as model proteins; the correlation coefficients （R2） of the standard curves for the quantitative method were 0.9994 and 0.9997, respectively, with each concentration ratio ranging from 0.1 to 10 and both relative standard derivations （RSD） measured at less than 5%. In T. tengcongensis at two incubation tem- peratures, 80 proteins possess quantitative information. In addition, compared with the proteins of T. tengcongensis incubated at 55 ℃, in T. tengcongensis incubated at 75 ℃, 7 proteins upregulate whereas 16 proteins downregulate, and most differential proteins are related to protein synthesis.