QTL Mapping of Seed Vigor of Backcross Inbred Lines Derived From Oryza longistaminata Under Artificial Aging

Seed vigor is an important character of seed quality that promotes rice to germinate rapidly from soil and developing to a strong seedling, especially in the current rice direct-sowing production system. However, previous studies for seed vigor mainly concentrate in cultivars, and less reports involving in wild rice. In this study, 152 backcross inbred lines (BILs) derived from wild rice Oryza longistaminata were genotyped with re-sequencing technology, and QTLs for seed vigor related traits under normal and artificial aging treatment were analyzed. Totally, 36 QTLs were detected, of which, eight for germination potential (GP), 10 for germination rate (GR), 9 for seedling length (SL), and 9 for root length (RL). Among these, 14 novel QTLs were identified from O. longistaminata. Of which, six QTLs were related to germination, and eight related to seedling growth under aging stress. What’s more, the major QTLs q9SL1.1, q6SL1.1, and q3SL1.1 for seedling length were fallen in the same locus and fine-mapped an interval about 90 Kb. The major QTLs q9GR8.1 and q9GP8.1 related with germination were fine-mapped to an interval about 90 Kb. This work will provide us basis for breeding of high seed vigor rice in rice breeding programs and further cloning of these genes

Development of Elite BPH-Resistant Wide-Spectrum Restorer Lines for Three and Two Line Hybrid Rice

Hybrid rice has contributed significantly to the world food security. Breeding of elite high-yield, strong-resistant broad-spectrum restorer line is an important strategy for hybrid rice in commercial breeding programs. Here, we developed three elite brown planthopper (BPH)-resistant wide-spectrum restorer lines by pyramiding big-panicle gene Gn8.1, BPH-resistant genes Bph6 and Bph9, fertility restorer genes Rf3, Rf4, Rf5, and Rf6 through molecular marker assisted selection. Resistance analysis revealed that the newly developed restorer lines showed stronger BPH-resistance than any of the single-gene donor parent Luoyang-6 and Luoyang-9. Moreover, the three new restorer lines had broad spectrum recovery capabilities for Honglian CMS, Wild abortive CMS and two-line GMS sterile lines, and higher grain yields than that of the recurrent parent 9,311 under nature field conditions. Importantly, the hybrid crosses also showed good performance for grain yield and BPH-resistance. Thus, the development of elite BPH-resistant wide-spectrum restorer lines has a promising future for breeding of broad spectrum BPH-resistant high-yield varieties

Synthesis, characterization, and visible-light photo-Fenton catalytic activity of hydroxy Fe/Al-intercalated montmorillonite

The photochemically assisted Fenton reaction (photo-Fenton) is important because it may be particularly effective for the degradation of harmful organic compounds in the environment using solar light. The purpose of the present study was to determine the effectiveness of hydroxy Fe/Al-intercalated montmorillonites (Fe/Al-Mt) as photo-Fenton catalysts. In particular, different Fe/Al molar ratios were of interest as a means to vary catalytic activity. Intercalation was achieved via an ion-exchange method and brilliant orange X-GN was the test compound for photodegradation by hydrogen peroxide (H O ) under visible-light irradiation (λ > 420 nm) in the presence of Fe/Al-Mt. The Fe/Al-Mt materials obtained were characterized by powder X-ray diffraction, N adsorption/desorption, X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopic analysis, and ultraviolet-visible spectroscopy. The decoloration performance of Fe/Al-Mt was investigated using different experimental parameters, including the synthesis method, the Fe/Al molar ratio of the intercalating solution, the catalyst dosage, the H O dosage, and the pH. The results of photo-Fenton reaction showed that the photocatalytic activity of Fe/Al-Mt was enhanced significantly by the extent of hydroxy Al/Fe intercalation. For optimal reaction conditions, 99.92% degradation efficiency of X-GN was achieved after 140 min of reaction. To obtain further information on the visible-light-assisted photo-Fenton process, a high-performance liquid chromatography-mass spectrometry method was applied to indentify the intermediate products and a degradation pathway was proposed

Sorption of Pyrene by Clay Minerals Coated with Dissolved Organic Matter (DOM) from Landfill Leachate

Interactions of dissolved organic matter (DOM) from landfill leachate with clays could affect significantly the fate of hydrophobic organic compounds (HOCs) in soils. The complexes of montmorillonite (MT) and kaolinite (KL) with DOM extracted from landfill leachate were prepared under controlled conditions, termed CMT and CKL, respectively. The bare clays and their complexes were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Batch experiments were designed to investigate the sorption behavior of pyrene onto the clays in the presence of DOM. The maximum sorption capacities of pyrene on MT, CMT, KL, and CKL were 22.18, 38.96, 42.00, and 44.99 μg·g−1, respectively, at the initial concentration of 1000 ± 150 μg·L−1. The sorption isotherms of pyrene by the bare clays followed the Henry model well, whereas the Freundlich sorption isotherm provided a better fit to the equilibrium data of the sorption by the complexes. The role of montmorillonite and kaolinite complexes with DOM in the retention of pyrene in soils was different. This may be due to the different crystal structures between montmorillonite and kaolinite

Effect of the Matrix and Target on the Accurate Quantification of Genomic and Plasmid DNA by Digital Polymerase Chain Reaction

In polymerase chain reaction (PCR)-based nucleic acid quantification, the DNA template type, primer/probe sequence, and instrument platform such as real-time quantitative PCR (qPCR) and digital PCR (dPCR) affect the accuracy and reliability of quantitative results. In this study, a plasmid DNA (pDNA) pBI121-screening, genetically modified (GM) rice SDrice genomic DNA (gDNA), and GM rapeseed SDrape gDNA, all carrying the same 11 screening elements, were used to prepare samples of different levels of gDNA and pDNA in a non-GM gDNA background. The comparison of the dPCR assays targeting the 11 screening elements revealed that the primer/probe set is a key factor that affects the accuracy of dPCR quantification. The optimal PCR method for the 11 screening elements was screened out from among the validated qPCR methods. The accuracy of the qPCR quantification of the low-level pDNA and gDNA test samples was low when pDNA was used as a calibrator, whereas that of the dPCR quantification was high and not affected by variations in template type and detection target. The validated dPCR assays targeting one or two elements can be randomly selected to characterize multiple-target pDNA reference materials (RMs). Low-level pDNA RMs with certified values can be used as quality controls for dPCR assays to avoid significant bias in gDNA quantification

Removal of reactive brilliant orange X-GN from aqueous solutions by MG-Al layered double hydroxides

Among the many techniques used to remove toxic dyes from the environment, layered double hydroxides (LDH) are considered to be especially environmentally friendly, but, this quality may be altered by variations in the octahedral Mg/Al molar ratios in the LDH structure. The aim of the present study was to synthesize environmentally sound LDH for use as an economically viable sorbent for the adsorption of reactive brilliant orange X-GN. Layered double hydroxides with Mg/Al molar ratios of 2:1 and 4:1 were prepared by co-precipitation. The materials obtained were characterized by powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray fluorescence spectroscopy (XRF), and surface-area analysis. Batch experiments were carried out to investigate the effects of contact time, pH, adsorbent dosage, and initial dye concentration on the adsorption behavior of the reactive brilliant orange X-GN by Mg-Al LDH. The results showed that the optimum pH value for dye adsorption was 3.0, at which the adsorption capacities of the reactive brilliant orange X-GN by the 2:1 LDH and the 4:1 LDH at 298 K were 79.370 mg/g and 83.343 mg/g, respectively. Further analysis of the dye-adsorption kinetics show that they fit the pseudo second-order model well. The adsorption equilibrium data showed that the Langmuir model provided better correlation of the equilibrium data than the Freundlich model. This result indicates that LDH provide specific homogeneous sites where monolayer dye adsorption occurs. The results of XRD and FTIR analyses of LDH before and after the dye adsorption demonstrated that the adsorption mechanisms were ion exchange and coulombic attraction

Novel QTLs from Wild Rice Oryza longistaminata Confer Strong Tolerance to High Temperature at Seedling Stage

Global warming poses a threat to rice production. Breeding heat-tolerant rice is an effective and economical approach to address this challenge. African rice is a valuable genetic resource for developing heat-tolerant crops due to its intricate mechanism for adapting to high temperatures. Oryza longistaminata, a widely distributed wild rice species in Africa, may harbor an even richer gene pool for heat tolerance, which remains untapped. In this study, we identified three heat tolerance QTLs from O. longistaminata at the seedling stage, including novel heat tolerance loci qTT4 and qTT5. Our findings demonstrated that the O. longistaminata alleles for these two QTLs can enhance the heat tolerance of rice seedlings. Remarkably, qTT5 was mapped to a region spanning approximately 287.2 kb, which contains 46 expressing genes. Through the analysis of Gene Ontology and expression differences under heat induction, we identified four candidate genes. Our results lay the foundation for discovering heat tolerance genes underlying O. longistaminata and developing new genetic resources for heat-tolerant rice breeding

Additional file 5: Table S4. of Artificial Selection of Gn1a Plays an Important role in Improving Rice Yields Across Different Ecological Regions

Primers used in this study. (DOC 30 kb