Application of Functional Markers to Identify Genes for Bacterial Blight Resistance in Oryza rufipogon

Field resistances of nine accessions of common wild rice （Oryza rufipogon Griff.） and one rice variety （IR24） were evaluated by using nine strains of bacterial blight pathogen （Xanthomonas oryzae pv. oryzae） from the Philippines. IR24 was highly susceptible to all the strains, and six common wild rice accessions resisted all the nine strains, with a resistance frequency of 67%. The accessions Yulin and Wanning were only susceptible to PXO280 and PXO71, respectively. The accession Gaozhou was susceptible to the three strains PXO79, PXO99 and PXO339, whereas resistant to the other six strains. It could be concluded that there is at least one resistance gene in each common wild rice accession. The functional markers of the genes xa5, xa13, Xa21 and Xa27 were used to detect the presence of these resistance genes in the nine tested wild rice accessions, and it was found that four wild rice accessions contained heterozygous xa13. Among the nine common wild rice accessions, five were homozygous for Xa27 and three homozygous for xa27, and the accession Laibin contained neither xa27 nor Xa27. In addition, there were no xa5 and Xa21 in all of these accessions.

Breeding of near-isogenic japonica rice lines with three major genes for resistance to bacterial blight

From 1986 to 1993, a set of near-isogenic japonicarice Iines with three major genes Xα-3, Xα - 4,and Xα-12 for resistance to bacterial blight(Xan-thomonas oryzae pv.oryzae)were developed anddesignated as CBB3, CBB4, and CBB12 respective-

Analyses of gene effects and inheritance of resistance to bacterial blight in rice

We analyzed the resistant inheritance of ajaponica variety,Jia23,to two bacterial blightpathogen strains,KS-6-6 and Zhe 173,rep-resenting respectively the two predominantpathogenic types(Ⅱ and Ⅳ)in the rice crop-ping area along the Yangtze River Valley.Jia23 was crossed with susceptible vari-eties,Ewan8 and 7416.Fplants were back-

Evaluatien of Near-lsogenic Rice Lines with 8 Genes for Bacterial Blight Resistance to Strains in China

A set of near-isogenic rice lines withmonogenic resistance to bacterial blight weredeveloped by IRRI.The Cultivar IR24 wasused as the recurred parent.They wereevaluated with 6 races of Xanthomonascampestris pv.oryzae(Xco)in the Philip-pines at the maximum tillering and the bootingstages by ZHANG and MEW at IRRI in 1989.

Characterization of root-associated bacterial community structures in soybean and corn using locked nucleic acid(LNA) oligonucleotide-PCR clamping and 454 pyrosequencing

supported in part by grants from the Strategic Priority Research Program of Chinese Academy of Sciences （XDB15010103）;the National Natural Science Foundation of China （41201247）

Identification of molecular markers linked to rice bacterial blight resistance genes from Oryza meyeriana

Y73 is a progeny of asymmetric somatic hybridization between Oryza sativa cv.Dalixiang and the wild rice species Oryza meyeriana.Inoculation with a range of strains of Xanthomonas oryzae pv.oryzae showed that Y73 had inherited a high level of resistance to rice bacterial blight(BB)from its wild parent.An F2 population of 7125 individuals was constructed from the cross between Y73 and a BB-susceptible cultivar IR24.After testing 615 SSR and STS markers covering the 12 rice chromosomes,186 markers were selected that showed polymorphism between Y73 and IR24.Molecular markers linked to the BB resistance genes in Y73 were scanned using the F2 population and the polymorphic markers.The SSR marker RM128 on chromosome 1,the STS marker R03D159 on chromosome 3 and the STS marker R05D104 on chromosome 5 were found to be linked to the rice BB resistance genes in Y73.

Expression,purification and immunocharacteristics of recombination UreB protein of H.pylori

INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat shock protein and vacuolating cytotoxin and so on ,and urease is an important factor in the colinization of the gastric mucosa and suspected to cause damage to the gastric mucosa[10-14].At the same time ,urdase is also one of the important protective antigens .

The expression and antigenicity identification of recombinant rat TGF-β1 in bacteria

In order to study structure-function details of TGF-beta1, the recombinant mature form of rat TGF-beta1 was expressed in bacteria. Synthesis of the 112 amino-acid carboxyl-terminal part of TGF-beta1 (amino acid 279-390) was controlled by an inducible gene expression system based on bacteriophage T7 RNA polymerase. This system allowed an active and selective synthesis of recombinant TGF-beta1. The molecular weight of expressed TGF-alpha1 monomer determined on SDS-polyacrylamide gel under reducing conditions was about 13 kD. Serial detergent washes combined with a single gel-filtration purification step were sufficient to purify the expression product to homogeneity. Amino-terminal sequencing revealed that the N-terminal of the recombinant protein was identical to the published data. In Western blot analysis the recombinant polypeptide showed excellent antigenicity against polyclonal TGF-beta1 antibody. The mature recombinant rat TGF-beta1 expressed in this study provides a useful tool for future detailed structural and functional studies.

The bacterial and host factors associated with extrapulmonary dissemination of Mycobacterium tuberculosis

With high morbidity and mortality worldwide, tuberculosis （TB） is still an important public health threat. The majority of human TB cases are caused by Mycobacterium tuberculosis. Although pulmonary TB is the most common presentation, M. tuberculosis can disseminate into other organs and causes extrapulmonary TB （EPTB）. The dissemination of bacteria from the initial site of infection to other organs can lead to fatal diseases, such as miliary and meningeal TB. Thoroughly understanding the mechanisms and pathways of dissemination would develop therapies to prevent the lethal prognosis of EPTB （miliary and meningeal TB） and vaccines to promote the development of adaptive immunity. This review focuses on risk factors of EPTB, bacterial and host genes involved in EPTB, and potential mechanisms of M. tuberculosis extrapulmonary dissemination.

Bacterial community composition and abundance in leachate of semi-aerobic and anaerobic landfills

The abundance and phylogenetic composition of bacterial community in leachate of semi-aerobic and anaerobic landfill were compared through real-time polymerase chain reaction and denaturing gradient gel electrophoresis. In semi-aerobic landfill scenario, the bacterial 16S rRNA copy numbers in leachate had no significant reduction from initial stage to stable period. In the scenario of anaerobic landfill, the largest bacterial 16S rRNA gene copy number was found in leachate at initial stage, but it reduced significantly at stable period. Moreover, methane-oxidizing bacteria population in stable period was lower than that in initial period in both two landfill processes. However, semi-aerobic landfill leachate had more methanotrophic bacteria populations than that in the anaerobic one. Furthermore, according to the sequences and phylogenetic analysis, obvious difference could be detected in bacterial community composition in different scenarios. Proteobacteria and bacteroidetes took up a dominantly higher proportion in semi-aerobic landfill leachate. To summarize up, different landfill methods and its landfill ages had crucial impacts on bacterial abundance and composition in leachate of semi-aerobic and anaerobic landfills.

Effect of reclaimed water effluent on bacterial community structure in the Typha angustifolia L. rhizosphere soil of urbanized riverside wetland, China

In order to evaluate the impact of reclaimed water on the ecology of bacterial communities in the Typha angustifolia L. rhizosphere soil, bacterial community structure was investigated using a combination of terminal restriction fragment length polymorphism and 16S rRNA gene clone library. The results revealed significant spatial variation of bacterial communities along the river from upstream and downstream. For example, a higher relative abundance of γ-Proteobacteria, Firmicutes, Chloroflexi and a lower proportion of β-Proteobacteria and ε-Proteobacteria was detected at the downstream site compared to the upstream site. Additionally, with an increase of the reclaimed water interference intensity, the rhizosphere bacterial community showed a decrease in taxon richness, evenness and diversity. The relative abundance of bacteria closely related to the resistant of heavy-metal was markedly increased, while the bacteria related for carbon/nitrogen/phosphorus/sulfur cycling wasn＇t strikingly changed. Besides that, the pathogenic bacteria markedly increased in the downstream rhizosphere soil since reclaimed water supplement, while the possible plant growth-promoting rhizobacteria obviously reduced in the downstream sediment. Together these data suggest cause and effect between reclaimed water input into the wetland, shift in bacterial communities through habitat change, and alteration of capacity for biogeochemical cycling of contaminants.