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The application of selenium (Se) can promote the growth of potatoes and increase the Se content of potato tubers. Nitrogen (N) can promote nutrient absorption and potato yield. However, the effects of Se and N on the yield and Se content of potato tubers have not been reported. Field experiments were conducted in 2019–2020 and 2020–2021. Three N levels, i.e., 0 kg N ha−1 (N0), 150 kg N ha−1 (N1) and 200 kg N ha−1 (N2), and three Se levels, i.e., 0 g Se ha−1 (Se0), 500 g Se ha−1 (Se1) and 1000 g Se ha−1 (Se2), were set up. Potato yield, root dry weight, root activity, leaf area index (LAI), net photosynthetic rate (Pn), malondialdehyde (MDA) content, antioxidant enzyme activity and Se content were investigated. N application increased root dry weight and activity, LAI, antioxidant enzymes activities, Se content and decreased MDA content. Pn, total potato yield and commercial potato yield first increased and then decreased with the increase in N application level. Se application increased root activity, Pn, antioxidant enzyme activities, total yield, commercial potato yield, commercial potato rate, Se content and decreased MDA content. In general, compared with the single application, the combination of N and Se fertilizers further promoted the growth of potatoes, increased the yield of potatoes and the Se content of potato pieces.

Background Chenopodium quinoa is a crop with outstanding tolerance to saline soil, but long noncoding RNAs (LncRNAs) expression profile driven by salt stress in quinoa has rarely been observed yet. Based on the high-quality quinoa reference genome and high-throughput RNA sequencing (RNA-seq), genome-wide identification of LncRNAs was performed, and their dynamic response under salt stress was then investigated. Results In total, 153,751 high-confidence LncRNAs were discovered and dispersed intensively in chromosomes. Expression profile analysis demonstrated significant differences between LncRNAs and coding RNAs. Under salt stress conditions, 4,460 differentially expressed LncRNAs were discovered, of which only 54 were differentially expressed at all the stress time points. Furthermore, a weighted co-expression network was then constructed to infer the potential biological functions of LncRNAs. Seven modules were significantly correlated with salt treatments, resulting in 210 hub genes, including 22 transcription factors and 70 LncRNAs. These results indicated that LncRNAs might interact with transcription factors to respond to salinity stress. Gene ontology enrichment of the coding genes of these modules showed that they were highly related to regulating metabolic processes, biological regulation and response to stress. Conclusions This study is the first report on genome-wide analysis of the LncRNAs responding to salt stress in quinoa. The findings will provide a solid framework for further functional research of salt responsive LncRNAs, contributing to quinoa genetic improvement.

Circularly polarized light (CPL) detection has emerged as a key technology for various optoelectronics. Chiral hybrid perovskites (CHPs) that combine CPL‐sensitive absorption induced by chiral organic ligands and superior photoelectric properties of perovskites are promising candidates for direct CPL detection. To date, most of the CHP detectors are made up of polycrystalline thin‐film, which results in a rather limited discrimination of CPL due to the existence of redundant impurities and intrinsic defect states originating from rapid crystallization process. Here, it is developed a direct CPL detector with high photocurrent and polarization selectivity based on low‐defect CHP single‐crystal nanowire arrays. Large‐scale CHP nanowires are obtained through a micropillar template‐assisted capillary‐bridge rise approach. Thanks to the high crystallinity and ordered crystallographic alignment of these arrays, a CPL photodetector with high light on/off ratio of 1.8 × 104, excellent responsivity of 1.4 A W−1, and an outstanding anisotropy factor of 0.24 for photocurrent has been achieved. These results would provide useful enlightenment for direct CPL detection in high‐performance chiral optoelectronics., An efficient circularly polarized light (CPL) detector is demonstrated with large‐scale chiral hybrid perovskite (CHP) nanowire arrays. Based on the high photocurrent and polarization selectivity of CHP single‐crystals, high‐performance CPL detectors with high light on/off ratio and excellent polarization distinguishability through arranging such single‐crystalline CHP nanowires into low‐defect arrays are achieved.

Potassium (K) is the essential element for plant growth. It is one of the critical factors that determine crop yield, quality, and especially leaf development in tobacco. However, the molecular mechanism of potassium use efficiency (KUE), especially non-coding RNA, is still unknown. In this study, tobacco seedlings were employed, and their hydro-cultivation with K treatments of low and sufficient concentrations was engaged. Physiological analysis showed that low potassium treatment could promote malondialdehyde (MDA) accumulation and antioxidant enzyme activities such as peroxidase (POD), ascorbate-peroxidase (APX). After transcriptomic analysis, a total of 10,585 LncRNA transcripts were identified, and 242 of them were significantly differently expressed under potassium starvation. Furthermore, co-expression networks were constructed and generated 78 potential regulation modules in which coding gene and LncRNAs are involved and functional jointly. By further module-trait analysis and module membership (MM) ranking, nine modules, including 616 coding RNAs and 146 LncRNAs, showed a high correlation with K treatments, and 20 hub K-responsive LncRNAs were finally predicted. Following gene ontology (GO) analysis, the results showed potassium starvation inducing the pathway of antioxidative stress which is consistent with the physiology result mentioned above. Simultaneously, a part of detected LncRNAs, such as

Secondary wall-associated NAC (SWN) genes are a subgroup of NAC (NAM, ATAF, and CUC) transcription factors (TF) that play a key role in regulating secondary cell wall biosynthesis in plants. However, this gene family has not been systematically characterized, and their potential roles in response to hormones are unknown in Nicotiana tabacum. In this study, a total of 40 SWN genes, of which 12 from Nicotiana tomentosiformis, 13 from Nicotiana sylvestris, and 15 from Nicotiana tabacum, were successfully identified. The 15 SWNs from Nicotiana tabacum were further classified into three groups, namely, vascular-related NAC domain genes (NtVNDs), NAC secondary wall thickening promoting factor genes (NtNSTs), and secondary wall-associated NAC domain genes (NtSNDs). The protein characteristic, gene structure, and chromosomal location of 15 NtSWNs (also named Nt1 to Nt15) were also analyzed. The NtVND and NtNST group genes had five conserved subdomains in their N-terminal regions and a motif (LP[Q/x] L[E/x] S[P/A]) in their diverged C- terminal regions. Some hormones, dark and low-temperature related cis-acting elements, were significantly enriched in the promoters of NtSWN genes. A comprehensive expression profile analysis revealed that Nt4 and Nt12 might play a role in vein development. Others might be important for stem development. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) revealed that in the NtNST group, genes such as Nt7, Nt8, and Nt13 were more sensitive than the genes in NtVND and NtSND groups under abiotic stress conditions. A transactivation assay further suggested that Nt7, Nt8, and Nt13 showed a significant transactivation activity. Overall, SWN genes were finally identified and characterized in diploid and tetraploid tobacco, revealing new insights into their evolution, variation, and homology relationships. Transcriptome, cis-acting element, qRT-PCR, and transactivation assay analysis indicated the roles in hormonal and stress responses, which provided further resources in molecular mechanism and genetic improvement.

Quinoa is a gluten-free food crop that contains all the essential amino acids and vitamins. The selection of proper housekeeping and tissue-specific genes is the crucial prerequisite for gene expression analysis using the common approach, real-time quantitative PCR (RT-qPCR). In this study, we identified 40 novel candidate housekeeping genes by the minimum transcript per million (TPM), coefficient of variation (CV) and maximum fold change (MFC) methods and 19 candidate tissue-specific genes by the co-expression network method based on an RNA-seq dataset that included 53 stem, leaf, flower and seed samples, as well as additional shoot and root samples under different stresses. The expression stability of 12 housekeeping and tissue-specific genes, as well as that of another two traditionally used housekeeping genes, was further evaluated using qPCR and ranked using NormFinder, BestKeeper and the comparative delta-Ct method. The results demonstrated that MIF, RGGA, VATE and UBA2B were ranked as the top four most stable candidate housekeeping genes. qPCR analysis also revealed three leaf-specific genes and five root-specific genes, but no stem-specific gene was identified. Gene Ontology (GO) enrichment analysis identified that housekeeping genes were mainly enriched in the small molecule metabolic process, organonitrogen compound metabolic process, NAD binding and ligase activity. In addition, tissue-specific genes are closely associated with the major functions of a specific tissue. Specifically, GO terms “photosynthesis” and “thylakoid” were most significantly overrepresented in candidate leaf-specific genes. The novel housekeeping and tissue-specific genes in our study will enable better normalization and quantification of transcript levels in quinoa.

Background Several studies have mined short-read RNA sequencing datasets to identify long non-coding RNAs (lncRNAs), and others have focused on the function of individual lncRNAs in abiotic stress response. However, our understanding of the complement, function and origin of lncRNAs – and especially transposon derived lncRNAs (TE-lncRNAs) - in response to abiotic stress is still in its infancy. Results We utilized a dataset of 127 RNA sequencing samples that included total RNA datasets and PacBio fl-cDNA data to discover lncRNAs in maize. Overall, we identified 23,309 candidate lncRNAs from polyA+ and total RNA samples, with a strong discovery bias within total RNA. The majority (65%) of the 23,309 lncRNAs had sequence similarity to transposable elements (TEs). Most had similarity to long-terminal-repeat retrotransposons from the Copia and Gypsy superfamilies, reflecting a high proportion of these elements in the genome. However, DNA transposons were enriched for lncRNAs relative to their genomic representation by ~ 2-fold. By assessing the fraction of lncRNAs that respond to abiotic stresses like heat, cold, salt and drought, we identified 1077 differentially expressed lncRNA transcripts, including 509 TE-lncRNAs. In general, the expression of these lncRNAs was significantly correlated with their nearest gene. By inferring co-expression networks across our large dataset, we found that 39 lncRNAs are as major hubs in co-expression networks that respond to abiotic stress, and 18 appear to be derived from TEs. Conclusions Our results show that lncRNAs are enriched in total RNA samples, that most (65%) are derived from TEs, that at least 1077 are differentially expressed during abiotic stress, and that 39 are hubs in co-expression networks, including a small number that are evolutionary conserved. These results suggest that lncRNAs, including TE-lncRNAs, may play key regulatory roles in moderating abiotic responses.

Several studies have mined short-read RNA sequencing datasets to identify lncRNAs, and others have focused on the function of individual lncRNA in abiotic stress response. However, our understanding of the complement, function and origin of long-non-coding RNA (lncRNAs) response to abiotic stress, especially transposon derived lncRNA (TE-lncRNA), is still in its infancy. To discover and study lncRNAs in maize (Zea mays ssp. mays), we utilized a dataset of 127 RNA sequencing samples that included PacBio fl-cDNA and total RNA-Seq datasets. Overall, we identified 23,309 candidate lncRNAs, 60% of which were identified in polyadenylated (polyA+) samples. The majority (65%) of the 23,309 lncRNAs had sequence similarity to transposable elements (TEs). Most had similarity to long-terminal-repeat retrotransposons from the Copia and Gypsy superfamilies, representing the high proportion of these elements in the genome, but class II, DNA transposons were enriched for lncRNAs relative to their genomic representation by 2-fold. By assessing the fraction of lncRNAs that respond to abiotic stresses like heat, cold, salt and drought, we identified 1,077 differentially expressed lncRNA transcripts. Their expression was correlated (r2=0.48) with their nearest gene, suggesting that lncRNAs are subject to some of the cis regulatory features as neighboring genes. By inferring co-expression networks across our large dataset, we found that 39 lncRNAs act as major hubs in co-expression networks, of which 18 appeared to be derived from TEs. These results suggest that lncRNAs, especially TE-lncRNAs, may play key regulatory roles in moderating abiotic responses.

Purpose To demonstrate a new MR imaging approach that unambiguously identifies and quantitates contrast agents based on intrinsic agent properties such as r1 , r2 , r2*, and magnetic susceptibility. The approach is referred to as magnetic barcode imaging (MBI). Methods Targeted and bioresponsive contrast agents were imaged in agarose phantoms to generate T1 , T2 , T2*, and quantitative susceptibility maps. The parameter maps were processed by a machine learning algorithm that is trained to recognize the contrast agents based on these parameters. The output is a quantitative map of contrast agent concentration, identity, and functional state. Results MBI allowed the quantitative interpretation of intensities, removed confounding backgrounds, enabled contrast agent multiplexing, and unambiguously detected the activation and binding states of bioresponsive and targeted contrast agents. Conclusion MBI has the potential to overcome significant limitations in the interpretation, quantitation, and multiplexing of contrast enhancement by MR imaging probes. Magn Reson Med 77:970-978, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Additional file 1: Figure S1. A schematic showing the data used in this paper, the bioinformatic pipeline for lncRNA identification, numbers of genes and identified lcRNAs, and some features of downstream lncRNA analyses. Figure S2. The chromosomal distribution of lncRNAs. Density was plotted across each chromosome. Figure S3. Differential expressed genes (DEGs) under different abiotic stresses. A-D, Venn diagram of DEGs under different stresses across different development stage V3-V6. E-G, Venn diagram of DEGs under different stress conditions at one stage. Figure S4. The correlation values (r) between each of the inferred coexpression modules and the specific traits (e.g., Heat, Cold) at different development times (e.g., V3 to V6). A subset of these data for the top 16 stress-associated modules is provided as a heat map in Figure 3. Figures S5-S9. These figures are the same format as that of Figure 4, but represent cold (Figure S5), drought (Figure S6), salt (Figure S7), UV (Figure S8) and ozone stress (Figure S9). Each figure contains a heat map (top) and graphs of the expression of specific TElncRNAs (bottom) that were chosen because they overrepresented with high interconnectivity. The heat graph shows transcript expression levels for genes and lncRNAs in each module (y-axis) and across conditions (x-axis). The key to modules (yaxis) and stress conditions (x-axis) are shown on the right legend, with conditions also separated by developmental stage (bottom of x-axis). Warmer colors within the heat map indicate high expression, and cooler colors are under-expression. The bar plots below the heat graph are eigen-lncRNA expression values selected from the top overrepresented lncRNAs with high interconnectivity. The x-axis is the same as the heat map, and the id of the lncRNAs is provided by the color key.

Here we present the 15 pseudochromosomes of sweet potato, Ipomoea batatas, the seventh most important crop in the world and the fourth most significant in China. By using a novel haplotyping method based on genome assembly, we have produced a half haplotype-resolved genome from ~296 Gb of paired-end sequence reads amounting to roughly 67-fold coverage. By phylogenetic tree analysis of homologous chromosomes, it was possible to estimate the time of two recent whole-genome duplication events as occurring about 0.8 and 0.5 million years ago. This half haplotype-resolved hexaploid genome represents the first successful attempt to investigate the complexity of chromosome sequence composition directly in a polyploid genome, using sequencing of the polyploid organism itself rather than any of its simplified proxy relatives. Adaptation and application of our approach should provide higher resolution in future genomic structure investigations, especially for similarly complex genomes.Assembly of polyploid plant genomes has been technically challenging. Now, a study presents a half haplotype-resolved hexaploid genome of sweet potato, Ipomoea batatas, using a novel haplotyping method.

High N loss and low N use efficiency (NUE), caused by high N fertilizer inputs and inappropriate fertilization patterns, have become important issues in the rice (Oryza sativa L.) growing regions of southern China. Changing current farmer fertilizer practice (FFP, 225 kg ha–1 N as three applications, 40% as basal fertilizer, 30% as tillering fertilizer and 30% as jointing fertilizer) to one—time root—zone fertilization (RZF, 225 kg ha–1 N applied once into 10 cm deep holes positioned 5 cm from the rice root as basal fertilizer) will address this problem. A two—year field experiment covering two rice growing regions was conducted to investigate the effect of urea one—time RZF on rice growth, nutrient uptake, and NUE. The highest NH4+–N content for RZF at fertilizer point at 30 d and 60 d after fertilization were 861.8 and 369.9 mg kg–1 higher than FFP, respectively. Rice yield and total N accumulation of RZF increased by 4.3–44.9% and 12.7–111.2% compared to FFP, respectively. RZF reduced fertilizer—N loss by 56.3–81.9% compared to FFP. The NUEs following RZF (mean of 65.8% for the difference method and 43.7% for the labelled method) were significantly higher than FFP (mean of 35.7% for the difference method and 14.4% for the labelled method). In conclusion, RZF maintained substantial levels of fertilizer—N in the root—zone, which led to enhanced rice biomass and N uptake during the early growth stages, increased fertilizer—N residual levels and reduced fertilizer—N loss at harvest. RZF produced a higher yield increment and showed an increased capacity to resist environmental threats than FFP in sandy soils. Therefore, adopting suitable fertilizer patterns plays a key role in enhancing agricultural benefits.

Although the sweet potato, Ipomoea batatas, is the seventh most important crop in the world and the fourth most significant in China, its genome has not yet been sequenced. The reason, at least in part, is that the genome has proven very difficult to assemble, being hexaploid and highly polymorphic; it has a presumptive composition of two B1 and four B2 component genomes (B1B1B2B2B2B2). By using a novel haplotyping method based on de novo genome assembly, however, we have produced a half haplotype-resolved genome from ∼267Gb of paired-end sequence reads amounting to roughly 60-fold coverage. By phylogenetic tree analysis of homologous chromosomes, it was possible to estimate the time of two whole genome duplication events as occurring about 525,000 and 341,000 years ago. Our analysis also identified many clusters of genes for specialized compounds biosynthesis in this genome. This half haplotype-resolved hexaploid genome represents the first successful attempt to investigate the complexity of chromosome sequence composition directly in a polyploid genome, using direct sequencing of the polyploid organism itself rather than of any of its simplified proxy relatives. Adaptation and application of our approach should provide higher resolution in future genomic structure investigations, especially for similarly complex genomes.

Ultrasmall (3, 4, 5, and 6 nm), water-soluble Fe3O4 magnetic nanoparticles were synthesized in diethylene glycol (DEG) via a facile one-pot reaction. Hydrodynamic size and relaxation time measurements did not show particle aggregation when Fe3O4 nanoparticles were dispersed in phosphate buffered saline, fetal bovine serum, or calf bovine serum for 1 week. Furthermore, the new Fe3O4 nanoparticles tolerated high salt concentrations (≤1 M NaCl) and a wide pH range from 5 to 11. Surface modification of the nanoparticles with poly(ethylene glycol) bis(carboxymethyl) ether (HOOC-PEG-COOH, 600 g/mol) was accomplished through a ligand-exchange reaction. The effects of PEG modification on magnetization and relaxivity of the Fe3O4 nanoparticles were investigated, and the results indicate that the increase in transverse relaxivity after PEG modification may be due to the increased volume of slowly diffusing water surrounding each nanoparticle. In vitro experiments showed that the DEG- and PEG-coated Fe3O4 nanoparticles have little effect on NIH/3T3 cell viability.

By one-pot reaction, biocompatible magnetite nanocrystals with surface reactive moieties were prepared through the thermal decomposition of Fe(acac)3 in 2-pyrrolidone using α , ω -dicarboxyl-terminated poly(ethylene glycol) as surface capping molecule. The successful conjugation between the magnetite nanocrystals and 9-amino acridine on the one hand demonstrates the existence of free carboxylic groups from PEG binding on the particle surface, on the other hand may also lead to a new type of magneto-optical materials as well as magneto-drugs.

To demonstrate a new MR imaging approach that unambiguously identifies and quantitates contrast agents based on intrinsic agent properties such as rTargeted and bioresponsive contrast agents were imaged in agarose phantoms to generate TMBI allowed the quantitative interpretation of intensities, removed confounding backgrounds, enabled contrast agent multiplexing, and unambiguously detected the activation and binding states of bioresponsive and targeted contrast agents.MBI has the potential to overcome significant limitations in the interpretation, quantitation, and multiplexing of contrast enhancement by MR imaging probes. Magn Reson Med 77:970-978, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

"H"-like organic nanowire heterojunctions with two parallel 2-acetyl-6-dimethylamino-naphthalene wires vertically bridged by one 2,4,5-triphenylimidazole wire are prepared via cooperative molecular assembly in liquid phase. The exciton conversion at the junction interfaces is beneficial for the design of multichannel light-controlled photo-switches. The results provide better understanding of molecular assembly toward specific structures and open up new prospects for the creation of novel photonic materials.

UNLABELLED • PREMISE OF THE STUDY There is an ongoing debate about the importance of whole-plant control vs. local modular mechanisms for root growth. We conducted a split-root experiment with different patch/background levels of nitrogen to examine whether local root growth and death are controlled by local resource levels or at the whole-plant level.• METHODS Three microrhizotrons with 0, 10, and 100 µg N/g growth medium levels (74 g growth medium each) were attached to pots of high or low soil N in which one Ailanthus altissima individual was growing. One fine root was guided into each of the microrhizotrons and photographed every 4 d. Plants were harvested after 28 d; root growth and mortality in the microrhizotrons were recorded. Changes in root length, number of laterals, and interlateral length were determined from the photos and analyzed.• KEY RESULTS While overall plant growth was influenced by background N level, both patch and background N levels influenced root growth and mortality in patches. Local roots proliferated most when the patch N level was high and background level low, and they proliferated least and showed highest mortality when patch N was low and the background level high.• CONCLUSIONS The fate of roots growing in a patch is influenced by the resource environment of the plant's other roots as well as the resource levels in the patch itself. Thus, the growth and death of roots in patches is determined by both modular and whole-plant mechanisms.

A one-pot reaction process was developed to synthesize highly dispersible, superparamagnetic Fe(3)O(4) nanoflowers; the potential of these nanoflowers as MRI contrast agents was investigated.

Magnetic resonance imaging (MRI) has become a powerful technique in biological molecular imaging and clinical diagnosis. With the rapid progress in nanoscale science and technology, nanostructure-based MR contrast agents are undergoing rapid development. This is in part due to the tuneable magnetic and cellular uptake properties, large surface area for conjugation and favourable biodistribution. In this review, we describe our recent progress in the development of high-performance nanostructured MR contrast agents. Specifically, we report on Gd-enriched nanostructured probes that exhibit T(1) MR contrast and superparamagnetic Fe(3)O(4) and CoFe(2)O(4) nanostructures that display T(2) MR contrast enhancement. The effects of nanostructure size, shape, assembly and surface modification on relaxivity are described. The potential of these contrast agents for in vitro and in vivo MR imaging with respect to colloidal stability under physiological conditions, biocompatibility, and surface functionality are also evaluated.