The mapping of functional genes plays an important role in studies of genome structure, function, and evolution, as well as allowing gene cloning and marker-assisted selection to improve agriculturally important traits. Simple sequence repeats (SSRs) developed from expressed sequence tags (ESTs), EST-SSR (eSSR), can be employed as putative functional marker loci to easily tag corresponding functional genes. In this paper, 2218 eSSRs, 1554 from G. raimondii-derived and 754 from G. hirsutum-derived ESTs, were developed and used to screen polymorphisms to enhance our backbone genetic map in allotetraploid cotton. Of the 1554 G. raimondii-derived eSSRs, 744 eSSRs were able to successfully amplify polymorphisms between our two mapping parents, TM-1 and Hai7124, presenting a polymorphic rate of 47.9%. However, only a 23.9% (159/754) polymorphic rate was produced from G. hirsutum-derived eSSRs. No relationship was observed between the level of polymorphism, motif type, and tissue origin, but the polymorphism appeared to be correlated with repeat type. After integrating these new eSSRs, our enhanced genetic map consists of 1790 loci in 26 linkage groups and covers 3425.8 cM with an average intermarker distance of 1.91 cM. This microsatellite-based, gene-rich linkage map contains 71.96% functional marker loci, of which 87.11% are eSSR loci. There were 132 duplicated loci bridging 13 homeologous At/Dt chromosome pairs. Two reciprocal translocations after polyploidization between A2 and A3, and between A4 and A5, chromosomes were further confirmed. A functional analysis of 975 ESTs producing 1122 eSSR loci tagged in the map revealed that 60% had clear BLASTX hits (,1e À10 ) to the Uniprot database and that 475 were associated mainly with genes belonging to the three major gene ontology categories of biological process, cellular component, and molecular function; many of the ESTs were associated with two or more category functions. The results presented here will provide new insights for future investigations of functional and evolutionary genomics, especially those associated with cotton fiber improvement.

In order to construct a saturated genetic map and facilitate marker-assisted selection (MAS) breeding, it is necessary to enhance the current reservoir of known molecular markers in Gossypium. Microsatellites or simple sequence repeats (SSRs) occur in expressed sequence tags (EST) in plants. Many ESTs are publicly available now and represent a good tool in developing EST-SSRs. From 13,505 ESTs developed from our two cotton fiber/ovule cDNA libraries constructed for Upland cotton, 966 (7.15%) contained one or more SSRs and from them, 489 EST-SSR primer pairs were developed. Among the EST-SSRs, 59.1% are trinucleotides, followed by dinucleotides (30%), tetranucleotides (6.4%), pentanucleotides (1.8%), and hexanucleotides (2.7%). AT/TA (18.4%) is the most frequent repeat, followed by CTT/GAA (5.3%), AG/TC (5.1%), AGA/TCT (4.9%), AGT/TCA (4.5%), and AAG/TTC (4.5%). One hundred and thirty EST-SSR loci were produced from 114 informative EST-SSR primer pairs, which generated polymorphism between our two mapping parents. Of these, 123 were integrated on our allotetraploid cotton genetic map, based on the cross [(TM-1xHai7124)TM-1]. EST-SSR markers were distributed over 20 chromosomes and 6 linkage groups in the map. These EST-SSR markers can be used in genetic mapping, identification of quantitative trait loci (QTLs), and comparative genomics studies of cotton.

Background: Upland cotton has the highest yield, and accounts for > 95% of world cotton production. Decoding upland cotton genomes will undoubtedly provide the ultimate reference and resource for structural, functional, and evolutionary studies of the species. Here, we employed GeneTrek and BAC tagging information approaches to predict the general composition and structure of the allotetraploid cotton genome.

Cannabis sativa L. is an important economic plant for the production of food, fiber, oils, and intoxicants. However, lack of sufficient simple sequence repeat (SSR) markers has limited the development of cannabis genetic research. Here, large-scale development of expressed sequence tag simple sequence repeat (EST-SSR) markers was performed to obtain more informative genetic markers, and to assess genetic diversity in cannabis (Cannabis sativa L.). Based on the cannabis transcriptome, 4,577 SSRs were identified from 3,624 ESTs. From there, a total of 3,442 complementary primer pairs were designed as SSR markers. Among these markers, trinucleotide repeat motifs (50.99%) were the most abundant, followed by hexanucleotide (25.13%), dinucleotide (16.34%), tetranucloetide (3.8%), and pentanucleotide (3.74%) repeat motifs, respectively. The AAG/CTT trinucleotide repeat (17.96%) was the most abundant motif detected in the SSRs. One hundred and seventeen EST-SSR markers were randomly selected to evaluate primer quality in 24 cannabis varieties. Among these 117 markers, 108 (92.31%) were successfully amplified and 87 (74.36%) were polymorphic. Forty-five polymorphic primer pairs were selected to evaluate genetic diversity and relatedness among the 115 cannabis genotypes. The results showed that 115 varieties could be divided into 4 groups primarily based on geography: Northern China, Europe, Central China, and Southern China. Moreover, the coefficient of similarity when comparing cannabis from Northern China with the European group cannabis was higher than that when comparing with cannabis from the other two groups, owing to a similar climate. This study outlines the first large-scale development of SSR markers for cannabis. These data may serve as a foundation for the development of genetic linkage, quantitative trait loci mapping, and marker-assisted breeding of cannabis.

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A self-consistent theory is developed based on the principle of relativity for a plane wave in a moving non-dispersive, lossless, non-conducting, isotropic uniform medium. Light-momentum criterion is set up for the first time, which states that the momentum of light in a medium is parallel to the wave vector in all inertial frames of reference. By rigorous analysis, novel basic properties of the plane wave are exposed: (1) Poynting vector does not necessarily represent the electromagnetic (EM) power flow when a medium moves, (2) Minkowski light momentum and energy constitute a Lorentz four-vector in a form of single EM-field cell or single photon, and Planck constant is a Lorentz invariant, (3) there is no momentum transfer taking place between the plane wave and the uniform medium, and the EM momentum conservation equation cannot be uniquely determined without resort to the principle of relativity, and (4) when the medium moves opposite to the wave vector at a faster-than-dielectric light speed, negative frequency and negative EM energy density occur, with the plane wave becoming left-handed. Finally, a new physics of so-called "intrinsic Lorentz violation" is presented as well.

Ramie (Boehmeria nivea L. Gaud) is one of the most important natural fiber crops, and improvement of fiber yield and quality is the main goal in efforts to breed superior cultivars. However, efforts aimed at enhancing the understanding of ramie genetics and developing more effective breeding strategies have been hampered by the shortage of simple sequence repeat (SSR) markers. In our previous study, we had assembled de novo 43,990 expressed sequence tags (ESTs). In the present study, we searched these previously assembled ESTs for SSRs and identified 1,685 ESTs (3.83%) containing 1,878 SSRs. Next, we designed 1,827 primer pairs complementary to regions flanking these SSRs, and these regions were designated as SSR markers. Among these markers, dinucleotide and trinucleotide repeat motifs were the most abundant types (36.4% and 36.3%, respectively), whereas tetranucleotide, pentanucleotide, and hexanucleotide motifs represented <10% of the markers. The motif AG/CT was the most abundant, accounting for 28.74% of the markers. One hundred EST-SSR markers (97 SSRs located in genes encoding transcription factors and 3 SSRs in genes encoding cellulose synthases) were amplified using polymerase chain reaction for detecting 24 ramie varieties. Of these 100 markers, 98 markers were successfully amplified and 81 markers were polymorphic, with 2–6 alleles among the 24 varieties. Analysis of the genetic diversity of all 24 varieties revealed similarity coefficients that ranged from 0.51 to 0.80. The EST-SSRs developed in this study represent the first large-scale development of SSR markers for ramie. These SSR markers could be used for development of genetic and physical maps, quantitative trait loci mapping, genetic diversity studies, association mapping, and cultivar fingerprinting.

Bio-organic fertilizers (BOFs) combine functional microbes with a suitable substrate and have been shown to effectively suppress soil-borne diseases and promote plant growth. Here, we developed a novel bio-organic fertilizer (BOF) by fermentation of a cow plus chicken manure (M) compost using Fen-liquor Daqu (FLD) as a fermentation starter and compared the compositions of bacterial and fungal communities in the rhizosphere soil of watermelon plants after treatment with different fertilizers. Further, we aimed to explore the mechanisms underlying plant-promoting and disease (Fusarium wilt)-suppressing activities of each rhizosphere microbial community. The microbial communities of soil amended with cow plus chicken manure compost (S+M), soil amended with the BOF (S+BOF), and untreated control soil (S) without plants were analyzed through sequence analysis using the Illumina MiSeq platform. The results showed that a new microbial community was formed in the manure compost after fermentation by the Daqu. Application of the BOF to the soil induced remarkable changes in the rhizosphere microbial communities, with increased bacterial diversity and decreased fungal diversity. Most importantly, S+BOF showed the lowest abundance of Fusarium. Moreover, watermelon quality was higher (P < 0.05) in the S+BOF than in the S+M treatment. Thus, application of the BOF favorably altered the composition of the rhizosphere microbial community, suppressing Fusarium wilt disease and promoting plant quality.