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Analysis of structure-activity relationships (SARs) at nano–bio interfaces is important for guiding the safe design of nanomaterials and the assessment of potential toxicity. Metal oxide (MeOx) nanomaterials are used in a wide range of applications due to their unique mechanical stability and optoelectronic properties. However, the increasing number of biosafety issues and exposure risks have led to a focus on the safety assessment of nanomaterials. Considering the wide range of MeOx nanomaterials and their various different properties, it is difficult to assess individual toxicities using traditional toxicological analyses. Nanometric quantitative structure–activity relationship (nano-QSAR) analysis offers new ideas for developing nano-informatics modeling. In this study, six physicochemical properties of 16 MeOx nanomaterials from different classes (MeO, MeO 2 , MeO 3 and Me 2 O 3) were standardized and ordered according to their weights based on the nano-QSAR analysis strategy to construct quasi -SMILES descriptors that can accurately measure the material property characteristics and finally achieve the prediction of material structural properties and bio-toxic effects. The modeling results suggest that the Zeta potential and the metal cation charge number of MeOx nanomaterials may be important parameters affecting the toxicity of associated materials. To further clarify the quantitative relationship between these two important properties and the final toxic endpoint, as well as the possible mechanism of damage, the toxicity mechanisms of four representative MeOx nanomaterials were further analyzed in this study using Caenorhabditis elegans. The results ultimately confirm that nanomaterials with higher absolute Zeta potential or higher metal cation charge may have the greater oxidative capacity and can cause more severe oxidative damage and free radical accumulation in nematodes via smaller uptake levels at the same survival rate. This study highlights the important influence of structural properties of MeOx nanomaterials on toxicity outcomes. Moreover, our data suggest that oxidative stress, an important mechanism of MeOx nanomaterial-induced damage, can be controlled by the material's Zeta potential and cationic charge number. This provides a novel strategy for the safe design and toxicity assessment of nanomaterials in the future. [Display omitted] • Different classes of 16 MeOx NMs were used to construct the nano-QSAR prediction model. • The SMILES-coding system characterizes the physicochemical characteristics of MeOx NMs. • The prediction model was constructed using the LC50 of C. elegans as the effect endpoint. • Oxidative stress is an essential cause of MeOx NMs causing C. elegans damage. • The zeta-potential or cationic charge is the primary internal factor of oxidative damage caused by MeOx NMs. [ABSTRACT FROM AUTHOR]

• The identified 65 Aux/IAA genes show an uneven chromosomal distribution in radish. • Six Aux/IAA genes exhibit specifically high expression level in radish root tissues. • RsIAA33 gene might involve in promoting taproot thickening and development in radish. Auxin/indole–3–acetic acid (Aux/IAA) genes encode short lived nuclear proteins that cooperated with auxin or auxin response factor (ARF), which are involved in plant growth and developmental processes. However, it's still ambiguous how the Aux/IAA genes regulate the process governing taproot thickening in radish. Herein, 65 Aux/IAA genes were identified from the radish genome. Gene duplication analysis showed that two pairs of tandem duplication and 17 (27%) segmental duplication events were identified among Aux/IAA family genes in radish. Transcriptomic analysis revealed that most of Aux/IAA genes (52/65) exhibited differential expression pattern in different root tissues, and six root–specific genes were highly expressed in root cortex, cambium, xylem, and root tip in radish. RT–qPCR analysis showed that the expression level of RsIAA33 was the highest at cortex splitting stage (CSS), and early expanding stage (ES). Furthermore, amiRNA–mediated gene silencing of RsIAA33 indicated that it could inhibit the reproductive growth, thus promoting taproot thickening and development. These results would provide valuable information for elucidating the molecular function of Aux/IAA genes involved in taproot thickening in radish. [ABSTRACT FROM AUTHOR]

Highlights • MeJA and SA have positive effects on GLS accumulation in radish taproot. • Differential expression of genes was observed under MeJA, SA and ABA treatments. • Myrosinase activity and SF content were highly sensitive to SA. • SF is correlated with myrosinase activity and GRA content. Abstract Radish is an important root vegetable crop. The effects of environmental stresses on glucosinolate (GLS) contents were extensively investigated in Brassicaceae species. However, little is known about the accumulation of GLS and sulforaphane (SF) in hormone-treated radish taproot. In this study, the effects of methyl jasmonate (MeJA), salicylic acid (SA) and abscisic acid (ABA) on the accumulation of GLS and SF in radish taproot were investigated. The GLS content increased considerably in response to MeJA treatment. Moreover, MeJA also up-regulated the expression level of several transcription factors and GLS biosynthesis related genes. The effects of SA on GLS content were less obvious, while ABA suppressed GLS biosynthesis. Additionally, the SF content increased under treatments with MeJA, SA and ABA. Furthermore, changes in myrosinase activity and glucoraphanin (GRA) content after the application of MeJA, SA and ABA were consistent with the changes in SF contents. The results indicated that the MeJA represents one of the most effective plant growth regulators (PGRs) for increasing the GLS content in radish taproot by up-regulating the expression levels of a few GLS biosynthetic related genes. These findings also implied that SF formation is correlated with myrosinase activity and GRA content in radish taproot. [ABSTRACT FROM AUTHOR]

Radish is an economical cool-season root vegetable crop worldwide. Heat shock protein 70 (HSP70) plays indispensable roles in plant growth, development and abiotic stress responses. Nevertheless, little information is available regarding the identification and functional characterization of HSP70 gene family in radish. Herein, a total of 34 RsHSP70 genes were identified at the radish genome level, among which nine and 25 RsHSP70s were classified into the HSP110/SSE and DnaK subfamilies, respectively. RNA-seq analysis revealed that some RsHSP70 genes had differential expression profile in radish leaf, root, stamen and pistil. A range of RsHSP70 genes exhibited differential expression under several abiotic stresses such as heat, salt and heavy metals. Intriguingly, the expression of four RsHSP70 genes (RsHSP70-7 , RsHSP70-12 , RsHSP70-20 and RsHSP70-22) was dramatically up-regulated under heat stress (HS). RT-qPCR and transient LUC reporter assay indicated that both the expression and promoter activity of RsHSP70-20 was strongly induced by HS. Notably, overexpression of RsHSP70-20 significantly enhanced thermotolerance by decreasing reactive oxygen species and promoting proline accumulation in radish, whereas its knock-down plants exhibited increased thermosensitivity, indicating that RsHSP70-20 positively regulate HS response in radish. These results would provide valuable information to decipher the molecular basis of RsHSP70 -mediated thermotolerance in radish. [Display omitted] • RsHSP70 gene family was systematically characterized at genome-wide level in radish. • Expression and promoter activity of RsHSP70-20 was markedly induced by heat stress. • Transgenic analysis reveals that RsHSP70-20 enhanced thermotolerance of radish plant. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) could be used in the field of biology and medicine as excellent nano-scale fluorescent probes due to their unique optical properties, but the adverse effects of QDs are always the obstruction for its usage in living organisms. In this study, we observed that CdTe QDs exposure decreased the cell viability while increased the apoptosis rates in the L929 cells. Apart from QD-induced oxidative stress indicated by excessive ROS generation, three signal transductions, including Akt, p38 and JNK, played important roles on the regulation of cell apoptosis by CdTe QDs exposure as well. In order to reduce the toxicity of CdTe QDs, we explored the protective effects of three treatments, i.e. resveratrol, H 2 S and thermotherapy at 43 °C, against the cell apoptosis elicited by CdTe QDs. The results showed that resveratrol, H 2 S and thermotherapy at 43 °C were capable of attenuating cell apoptosis and intercellular ROS production through inhibiting signal pathways of Akt, p38 and JNK, respectively. As there is only limited number of exogenous treatments reported to diminish the toxicity of QDs, our findings will provide a novel insight for researchers who try to reduce or even eliminate the adverse health effects of QDs. [ABSTRACT FROM AUTHOR]

• Totally 42 members of the Histone gene family were firstly identified in radish. • Seven RsCENH3 genes exhibited specifically high expression level in the radish bud. • RsCENH3 gene might be involved in promoting microspore development in radish. Histone, a predominant protein component of chromatin, participates in DNA packaging and transcriptional regulation. However, the available information of Histone gene family is limited in radish. In this study, a total of 42 Histone gene family members were identified from the radish genome. Sequence alignment and phylogenetic analyses classified the Histone family into three groups (H2A, H2B and H3). Motif analysis showed that the functions of some motifs shared by H3 subfamily genes were related to chromosome regulation and cell development activities, such as motif 5 containing Cks1 and PPR region. Analysis of intron/exon structure indicated that RsCENH3 (RsHistone 18) has the characteristics of variant Histone. Furthermore, several motifs, including the LTR, G-box and TC-elements, were found in the promoters of RsHistone genes, which involved in cell development or various abiotic stresses responses. Transcriptome analysis indicated that the RsHistone genes exhibited higher expression level in floral buds than in roots and leaves. Subcellular localization showed that the RsCENH3 was localized on the nucleus, and it was highly expressed in the floral bud of 3.0–4.0 mm in radish. These findings would provide valuable information for characterization and potential utilization of Histone genes, and facilitate the efficient induction of double haploid plants in radish. [ABSTRACT FROM AUTHOR]