Despite a substantial investment in the development of panels of single nucleotide polymorphism (SNP) markers, the simple sequence repeat (SSR) technology with a limited multiplexing capability remains a standard, even for applications requiring whole-genome information. Diversity arrays technology (DArT) types hundreds to thousands of genomic loci in parallel, as previously demonstrated in a number diploid plant species. Here we show that DArT performs similarly well for the hexaploid genome of bread wheat (Triticum aestivum L.). The methodology previously used to generate DArT fingerprints of barley also generated a large number of high-quality markers in wheat (99.8% allele-calling concordance and approximately 95% call rate). The genetic relationships among bread wheat cultivars revealed by DArT coincided with knowledge generated with other methods, and even closely related cultivars could be distinguished. To verify the Mendelian behaviour of DArT markers, we typed a set of 90 Cranbrook x Halberd doubled haploid lines for which a framework (FW) map comprising a total of 339 SSR, restriction fragment length polymorphism (RFLP) and amplified fragment length polymorphism (AFLP) markers was available. We added an equal number of DArT markers to this data set and also incorporated 71 sequence tagged microsatellite (STM) markers. A comparison of logarithm of the odds (LOD) scores, call rates and the degree of genome coverage indicated that the quality and information content of the DArT data set was comparable to that of the combined SSR/RFLP/AFLP data set of the FW map.

Understanding the distribution of genetic diversity among individuals, populations and gene pools is crucial for the efficient management of germplasm collections and breeding programs. Diversity analysis is routinely carried out using sequencing of selected gene(s) or molecular marker technologies. Here we report on the development of Diversity Arrays Technology (DArT) for pigeonpea (Cajanus cajan) and its wild relatives. DArT tests thousands of genomic loci for polymorphism and provides the binary scores for hundreds of markers in a single hybridization-based assay. We tested eight complexity reduction methods using various combinations of restriction enzymes and selected PstI/HaeIII genomic representation with the largest frequency of polymorphic clones (19.8%) to produce genotyping arrays. The performance of the PstI/HaeIII array was evaluated by typing 96 accessions representing nearly 20 species of Cajanus. A total of nearly 700 markers were identified with the average call rate of 96.0% and the scoring reproducibility of 99.7%. DArT markers revealed genetic relationships among the accessions consistent with the available information and systematic classification. Most of the diversity was among the wild relatives of pigeonpea or between the wild species and the cultivated C. cajan. Only 64 markers were polymorphic among the cultivated accessions. Such narrow genetic base is likely to represent a serious impediment to breeding progress in pigeonpea. Our study shows that DArT can be effectively applied in molecular systematics and biodiversity studies.

Understanding the distribution of genetic diversity within and among individuals, populations, species and gene pools is crucial for the efficient management of germplasm collections. Molecular markers are playing an increasing role in germplasm characterization, yet their broad application is limited by the availability of markers, the costs and the low throughput of existing technologies. This is particularly true for crops of resource-poor farmers such as cassava, Manihot esculenta. Here we report on the development of Diversity Arrays Technology (DArT) for cassava. DArT uses microarrays to detect DNA polymorphism at several hundred genomic loci in a single assay without relying on DNA sequence information. We tested three complexity reduction methods and selected the two that generated genomic representations with the largest frequency of polymorphic clones (PstI/TaqI: 14.6%, PstI/BstNI: 17.2%) to produce large genotyping arrays. Nearly 1,000 candidate polymorphic clones were detected on the two arrays. The performance of the PstI/TaqI array was validated by typing a group of 38 accessions, 24 of them in duplicate. The average call rate was 98.1%, and the scoring reproducibility was 99.8%. DArT markers displayed fairly high polymorphism information content (PIC) values and revealed genetic relationships among the samples consistent with the information available on these samples. Our study suggests that DArT offers advantages over current technologies in terms of cost and speed of marker discovery and analysis. It can therefore be used to genotype large germplasm collections.

To further reduce the total phenols of coal-gasification wastewater which comes from the Lurgi pressurized coal-gasification process, methyl isobutyl ketone (MIBK) instead of diisopropyl ether (DIPE) is used as the extraction solvent in the process to remove the phenols. To obtain process parameters for an industrial trial, process simulations with a treatment capacity of 100 ton/h wastewater are carried out. The simulation results show that with the use of MIBK as an extraction solvent, the total phenol concentration of coal-gasification wastewater can be reduced from 5410 ppm to less than 200 ppm. The operation cost estimate shows that using MIBK as an extraction solvent to extract and remove phenols from coal-gasification wastewater has good economic feasibility. With the process parameters obtained from the simulation, an industrial trial is implemented and satisfactory agreement is found. With the total phenol concentration reduced to below 200 ppm in the pretreatment, the coal-gasification wastewater can be decontaminated in the subsequent biological treatment.

Summary Vitellogenin (Vg) is a well‐known nutritious protein involved in reproduction in nearly all oviparous animals, including insects. Recently, Vg has been detected in saliva proteomes of several piercing–sucking herbivorous arthropods, including the small brown planthopper (Laodelphax striatellus, SBPH). Its function, however, remains unexplored. We investigated the molecular mechanism underlying SBPH orally secreted Vg‐mediated manipulation of plant–insect interaction by RNA interference, phytohormone and H2O2 profiling, protein–protein interaction studies and herbivore bioassays. A C‐terminal polypeptide of Vg (VgC) in SBPH, when secreted into rice plants, acted as a novel effector to attenuate host rice defenses, which in turn improved insect feeding performance. Silencing Vg reduced insect feeding and survival on rice. Vg‐silenced SBPH nymphs consistently elicited higher H2O2 production, a well‐established defense mechanism in rice, whereas expression of VgC in planta significantly hindered hydrogen peroxide (H2O2) accumulation and promoted insect performance. VgC interacted directly with the rice transcription factor OsWRKY71, a protein which is involved in induction of H2O2 accumulation and plant resistance to SBPH. These findings indicate a novel effector function of Vg: when secreted into host rice plants, this protein effectively weakened H2O2‐mediated plant defense through its association with a plant immunity regulator.

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BACKGROUND Calcium (Ca2+)‐binding proteins in the saliva of herbivorous insects function as effectors to attenuate host plant defenses and thus improve insect feeding performance. Silencing these genes via transgenic plant‐mediated RNAi is thus a promising pest control strategy. However, their sequences and functions in the small brown planthopper Laodelphax striatellus (SBPH) remain to be investigated. RESULTS We identified a putative EF‐hand Ca2+‐binding protein (LsECP1) in SBPH watery saliva. LsECP1 was expressed extremely high in the salivary glands but at a low level during the egg stage. Transient LsECP1 expression in rice cells indicated its cytoplasm and nucleus localization. The bacterially expressed recombinant LsECP1 protein exhibited Ca2+‐binding activity. Rice plants fed by SBPH nymphs with knocked down LsECP1 exhibited higher levels of cytosolic Ca2+, jasmonic acid (JA), jasmonoyl‐isoleucine (JA‐Ile) and hydrogen peroxide (H2O2). Consistently, application of heterogeneously expressed LsECP1 protein suppressed wound‐induced JA, JA‐Ile and H2O2 accumulation in rice. Thus, LsECP1 knockdown by dsRNA injection resulted in reduced feeding, fecundity and survival rates of SBPH reared on rice plants. Transgenic rice plants constitutively expressing LsECP1 dsRNA were produced, and plant‐mediated LsECP1 knockdown enhanced rice resistance to SBPH. CONCLUSION SBPH LsECP1 acts as an effector to impair host rice defense responses and promotes SBPH performance. This discovery provides a potential gene target for plant‐mediated RNAi‐based pest management. © 2021 Society of Chemical Industry

In recent years, developing alternative liquid to fossil fuels has drawn much attention from world industry. In China, the coal/biomass-based Fischer−Tropsch (FT) liquid is a promising alternative to address the shortage of petroleum supplies. However, there is a lack of systematic and quantitative assessment of sustainability of these processes. This paper proposes a multi-dimensional set of metrics to assess sustainability performance of the coal/biomass to FT liquids processes in China. The assessment indicates that the coal-to-FT fuel process performs well in technical and economic aspects, while unsatisfactorily in relation to environmental features. Besides, the production potential of coal-to-FT in China by 2020 is rather limited. On the other hand, the biomass-to-FT fuel process shows great potential for replacement of petroleum-derived fuels and good environmental performance, although it does not perform well in terms of economic and technical characteristics at present. Co-processing biomass with coal to make FT fuel is a preferable compromise option for its low GHG emissions and good economic performance, although further investigations and technical improvements are needed.