High-density SNP map facilitates fine mapping of QTLs and candidate genes discovery for Aspergillus flavus resistance in peanut (Arachis hypogaea).

KEY MESSAGE: Two novel resistant QTLs mapped and candidate genes identified for Aspergillus flavus resistance in cultivated peanut using SLAF-seq. Aflatoxin contamination in peanuts caused by Aspergillus flavus is a serious food safety issue for human health around the world. Host plant resistance to fungal infection and reduction in aflatoxin are crucial for mitigating this problem. Identification of the resistance-linked markers can be used in marker-assisted breeding for varietal development. Here we report construction of two high-density genetic linkage maps with 1975 SNP loci and 5022 SNP loci, respectively. Two consistent quantitative trait loci (QTL) were identified as qRAF-3-1 and qRAF-14-1, which located on chromosomes A03 and B04, respectively. QTL qRAF-3-1 was mapped within 1.67 cM and had more than 19% phenotypic variance explained (PVE), while qRAF-14-1 was located within 1.34 cM with 5.15% PVE. While comparing with the reference genome, the mapped QTLs, qRAF-3-1 and qRAF-14-1, were located within a physical distance of 1.44 Megabase pair (Mbp) and 2.22 Mbp, harboring 67 and 137 genes, respectively. Among the identified candidate genes, six genes with the same function were found within both QTLs regions. In addition, putative disease resistance RPP13-like protein 1 (RPP13), lipoxygenase (Lox), WRKY transcription factor (WRKY) and cytochrome P450 71B34 genes were also identified. Using microarray analysis, genes responded to A. flavus infection included coding for RPP13, pentatricopeptide repeat-containing-like protein, and Lox which may be possible candidate genes for resistance to A. flavus. The QTLs and candidate genes will further facilitate marker development and validation of genes for deployment in the molecular breeding programs against A. flavus in peanuts.

3D X-ray micro-computed tomography imaging for the microarchitecture evaluation of porous metallic implants and scaffolds.

As an advanced microscopy technology with strong sample adaptability and non-destructive three-dimensional (3D) characteristics, X-ray micro-computed tomography (Micro-CT) can establish the overall connection between various microarchitecture parameters and accelerate the research process of porous metallic implants and scaffolds. In this review, the Micro-CT based quantitative evaluation methods of microarchitecture and bone formation are investigated. To ensure reliability of the results, the Micro-CT setup is discussed briefly and the essential image processing algorithms are introduced in detail. The significance and limitations of Micro-CT are analyzed in the context of research on porous metallic implants. We also discuss the future development of Micro-CT technology in the field of biological tissue engineering.

Ectopic Expression of AhGLK1b (GOLDEN2-like Transcription Factor) in Arabidopsis Confers Dual Resistance to Fungal and Bacterial Pathogens.

GOLDEN2-LIKE (GLK) is a member of the myeloblastosis (MYB) family transcription factor and it plays an important role in the regulation of plastid development and stress tolerance. In this study, a gene named AhGLK1b was identified from a cultivated peanut showing down-regulation in response to low calcium with a complete open reading frame (ORF) of 1212 bp. The AhGLK1b has 99.26% and 96.28% sequence similarities with its orthologs in Arachis ipaensis and A. duranensis, respectively. In the peanut, the AhGLK1b was localized in the nucleus and demonstrated the highest expression in the leaf, followed by the embryo. Furthermore, the expression of AhGLK1b was induced significantly in response to a bacterial pathogen, Ralstonia solanacearum infection. Ectopic expression of AhGLK1b in Arabidopsis showed stronger resistance against important phytopathogenic fungi S. sclerotiorum. It also exhibited high resistance to infection of the bacterial pathogen Pst DC3000. AhGLK1b-expressing Arabidopsis induced defense-related genes including PR10 and Phox/Bem 1 (PBI), which are involved in multiple disease resistance. Taken together, the results suggest that AhGLK1b might be useful in providing dual resistance to fungal and bacterial pathogens as well as tolerance to abiotic stresses.

Effects of intermittent pressure imitating rolling manipulation in traditional Chinese medicine on ultrastructure and metabolism in injured human skeletal muscle cells.

Skeletal muscle injuries can cause significant change in the ultrastructure and the metabolism of the skeletal muscle cells. Observation of the ultrastructure and measurements of the metabolism biomarkers such as total superoxide dismutase (T-SOD), malondialdehyde (MDA), and creatine kinase (CK) can be used to evaluate the degree of damage in human skeletal muscle injury. Rolling manipulation is the most popular myofascial release technique in Traditional Chinese Medicine. This study aimed to investigate the effects of intermittent pressure imitating rolling manipulation (IPIRM) of Traditional Chinese Medicine on ultrastructure and metabolism in the injured HSKMCs. Methods: In vitro techniques were used to culture HSKMCs, which were injured with high doses of dexamethasone sodium phosphate. Cells were divided into four groups-control normal group (CNG), control injured group (CIG), rolling manipulation group (RMG), and sine pressure group (SPG). RMG and SPG cells were cyclically exposed to 3.0 Kg (6.6 Pounds) of maximum force at a frequency of 2.0 Hz for 10 min in the Flexcell compression system for duration of 3 days continually. The cell ultrastructure, total superoxide dismutase (T-SOD) activity, malondialdehyde (MDA) content, and creatine kinase (CK) activity of the groups were assessed. Conclusion: These results suggest that the mechanical effects of rolling manipulation in TCM could not only improve the recovery of injured skeletal muscle cells by ameliorating organelles arrangement, reducing organelle swelling, and maintaining nuclear membrane integrity, but also ameliorate the functions of cellular metabolism by increasing T-SOD activity and decreasing MDA content and CK activity in injured skeletal muscle. Then the Hippo/Yap signal pathway was detected, and the proteins in each group were detected by Western Blot. The protein expression of upstream protein p-LATS1 and downstream protein p-Yap (Ser127) in each group was observed to explore the biomechanical mechanism of the method. The relative protein expression of p-LATS1 and p-Yap in (RMG) group was significantly higher than that in injured (CIG) group (P < 0.05). It was suggested that Hippo/Yap pathway was related to the stimulation of 3D human skeletal muscle cells, and the proliferation pathway of 3D human skeletal muscle cells could be opened by stimulation of three dimensional human skeletal muscle cells. It may be one of the biological mechanisms caused by the mechanical effects of manipulations in TCM.

The genome of cultivated peanut provides insight into legume karyotypes, polyploid evolution and crop domestication.

High oil and protein content make tetraploid peanut a leading oil and food legume. Here we report a high-quality peanut genome sequence, comprising 2.54 Gb with 20 pseudomolecules and 83,709 protein-coding gene models. We characterize gene functional groups implicated in seed size evolution, seed oil content, disease resistance and symbiotic nitrogen fixation. The peanut B subgenome has more genes and general expression dominance, temporally associated with long-terminal-repeat expansion in the A subgenome that also raises questions about the A-genome progenitor. The polyploid genome provided insights into the evolution of Arachis hypogaea and other legume chromosomes. Resequencing of 52 accessions suggests that independent domestications formed peanut ecotypes. Whereas 0.42-0.47 million years ago (Ma) polyploidy constrained genetic variation, the peanut genome sequence aids mapping and candidate-gene discovery for traits such as seed size and color, foliar disease resistance and others, also providing a cornerstone for functional genomics and peanut improvement.

Near-atomic structure of Japanese encephalitis virus reveals critical determinants of virulence and stability.

Although several different flaviviruses may cause encephalitis, Japanese encephalitis virus is the most significant, being responsible for thousands of deaths each year in Asia. The structural and molecular basis of this encephalitis is not fully understood. Here, we report the cryo-electron microscopy structure of mature Japanese encephalitis virus at near-atomic resolution, which reveals an unusual "hole" on the surface, surrounded by five encephalitic-specific motifs implicated in receptor binding. Glu138 of E, which is highly conserved in encephalitic flaviviruses, maps onto one of these motifs and is essential for binding to neuroblastoma cells, with the E138K mutation abrogating the neurovirulence and neuroinvasiveness of Japanese encephalitis virus in mice. We also identify structural elements modulating viral stability, notably Gln264 of E, which, when replaced by His264 strengthens a hydrogen-bonding network, leading to a more stable virus. These studies unveil determinants of neurovirulence and stability in Japanese encephalitis virus, opening up new avenues for therapeutic interventions against neurotropic flaviviruses.Japanese encephalitis virus (JEV) is a Flavivirus responsible for thousands of deaths every year for which there are no specific anti-virals. Here, Wang et al. report the cryo-EM structure of mature JEV at near-atomic resolution and identify structural elements that modulate stability and virulence.

A single mutation in the prM protein of Zika virus contributes to fetal microcephaly.

Zika virus (ZIKV) has evolved into a global health threat because of its unexpected causal link to microcephaly. Phylogenetic analysis reveals that contemporary epidemic strains have accumulated multiple substitutions from their Asian ancestor. Here we show that a single serine-to-asparagine substitution [Ser139→Asn139 (S139N)] in the viral polyprotein substantially increased ZIKV infectivity in both human and mouse neural progenitor cells (NPCs) and led to more severe microcephaly in the mouse fetus, as well as higher mortality rates in neonatal mice. Evolutionary analysis indicates that the S139N substitution arose before the 2013 outbreak in French Polynesia and has been stably maintained during subsequent spread to the Americas. This functional adaption makes ZIKV more virulent to human NPCs, thus contributing to the increased incidence of microcephaly in recent ZIKV epidemics.