A tripartite rheostat controls self-regulated host plant resistance to insects.

Plants deploy receptor-like kinases and nucleotide-binding leucine-rich repeat receptors to confer host plant resistance (HPR) to herbivores1. These gene-for-gene interactions between insects and their hosts have been proposed for more than 50 years2. However, the molecular and cellular mechanisms that underlie HPR have been elusive, as the identity and sensing mechanisms of insect avirulence effectors have remained unknown. Here we identify an insect salivary protein perceived by a plant immune receptor. The BPH14-interacting salivary protein (BISP) from the brown planthopper (Nilaparvata lugens Stål) is secreted into rice (Oryza sativa) during feeding. In susceptible plants, BISP targets O. satvia RLCK185 (OsRLCK185; hereafter Os is used to denote O. satvia-related proteins or genes) to suppress basal defences. In resistant plants, the nucleotide-binding leucine-rich repeat receptor BPH14 directly binds BISP to activate HPR. Constitutive activation of Bph14-mediated immunity is detrimental to plant growth and productivity. The fine-tuning of Bph14-mediated HPR is achieved through direct binding of BISP and BPH14 to the selective autophagy cargo receptor OsNBR1, which delivers BISP to OsATG8 for degradation. Autophagy therefore controls BISP levels. In Bph14 plants, autophagy restores cellular homeostasis by downregulating HPR when feeding by brown planthoppers ceases. We identify an insect saliva protein sensed by a plant immune receptor and discover a three-way interaction system that offers opportunities for developing high-yield, insect-resistant crops.

Facile Synthesis of Nano-Flower ß-Bi2O3/TiO2 Heterojunction as Photocatalyst for Degradation RhB.

Photocatalysis is a hopeful technology to solve various environmental problems, but it is still a technical task to produce large-scale photocatalysts in a simple and sustainable way. Here, nano-flower ß-Bi2O3/TiO2 composites were prepared via a facile solvothermal method, and the photocatalytic performances of ß-Bi2O3/TiO2 composites with different Bi/Ti molar ratios were studied. The nano-flower Bi2O3/TiO2 composites were studied by SEM, XRD, XPS, BET, and PL. The PL result proved that the construction of staggered heterojunction enhanced the separation efficiency of carriers. The degradation RhB was applied to study the photocatalytic performances of prepared materials. The results showed that the degradation efficiency of RhB increased from 61.2% to 99.6% when the molar ratio of Bi/Ti was 2.1%. It is a mesoporous approach to enhance photocatalytic properties by forming heterojunction in Bi2O3/TiO2 composites, which increases the separation efficiency of the generated carriers and improves photocatalytic properties. The photoactivity of the Bi2O3/TiO2 has no evident changes after the fifth recovery, indicating that the Bi2O3/TiO2 composite has distinguished stability.

Secretome Analysis and In Planta Expression of Salivary Proteins Identify Candidate Effectors from the Brown Planthopper Nilaparvata lugens.

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a phloem sap-feeding insect. During feeding on rice plants, BPH secretes salivary proteins with potential effector functions, which may play a critical role in the plant-insect interactions. However, a limited number of BPH effector proteins have been identified to date. Here, we sequenced the salivary gland transcriptomes of five BPH populations and subsequently established a N. lugens secretome consisting of 1,140 protein-encoding genes. Secretome analysis revealed the presence of both conserved and rapidly evolving salivary proteins. A screen for potential effectors that elicit responses in the plant was performed via the transient expression analysis of 64 BPH salivary proteins in Nicotiana benthamiana leaves and rice protoplasts. The salivary proteins Nl12, Nl16, Nl28, and Nl43 induced cell death, whereas Nl40 induced chlorosis and Nl32 induced a dwarf phenotype in N. benthamiana, indicating effector properties of these proteins. Ectopic expression of the six salivary proteins in N. benthamiana upregulated expression of defense-related genes and callose deposition. Tissue expression analysis showed a higher expression level of the six candidate effectors in salivary glands than in other tissues. Subcellular localization and analysis of the domain required for cell death showed a diverse structure of the six effectors. Nl28, Nl40, and Nl43 are N. lugens specific; in contrast, Nl12, Nl16, and Nl32 are conserved among insects. The Nl40 family has numerous isoforms produced by alternative splicing, exemplifying rapid evolution and expansion of effector proteins in the BPH. Our results suggest a potential large effector repertoire in BPH and a higher level of effector conservation exist in BPH compared with that in plant pathogens.

A Mucin-Like Protein of Planthopper Is Required for Feeding and Induces Immunity Response in Plants.

The brown planthopper, Nilaparvata lugens, is a pest that threatens rice (Oryza sativa) production worldwide. While feeding on rice plants, planthoppers secrete saliva, which plays crucial roles in nutrient ingestion and modulating plant defense responses, although the specific functions of salivary proteins remain largely unknown. We identified an N. lugens-secreted mucin-like protein (NlMLP) by transcriptome and proteome analyses and characterized its function, both in brown planthopper and in plants. NlMLP is highly expressed in salivary glands and is secreted into rice during feeding. Inhibition of NlMLP expression in planthoppers disturbs the formation of salivary sheaths, thereby reducing their performance. In plants, NlMLP induces cell death, the expression of defense-related genes, and callose deposition. These defense responses are related to Ca2+ mobilization and the MEK2 MAP kinase and jasmonic acid signaling pathways. The active region of NlMLP that elicits plant responses is located in its carboxyl terminus. Our work provides a detailed characterization of a salivary protein from a piercing-sucking insect other than aphids. Our finding that the protein functions in plant immune responses offers new insights into the mechanism underlying interactions between plants and herbivorous insects.

The central nervous system is a target of acute graft versus host disease in mice.

Despite significant advances in prevention and management, graft versus host disease (GVHD) is still a leading complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although skin, gut, liver, thymus, and lung are GVHD targets, neurological complications (NC) have also been reported following allo-HSCT. We demonstrate that the central nervous system (CNS) can be a direct target of alloreactive T cells following allo-HSCT in mice. We found significant infiltration of the CNS with donor T lymphocytes and cell death of neurons and neuroglia in allo-HSCT recipients with GVHD. We also found that allo-HSCT recipients with GVHD had deficits in spatial learning/memory and demonstrated increased anxious behavior. These findings highlight CNS sensitivity to damage caused by alloreactive donor T cells and represent the first characterization of target cell subsets and NC during GVHD. Therefore, these clinically relevant studies offer a novel and rational explanation for the well-described neurological symptoms observed after allo-HSCT.

Intraspecific and Interspecific Variations in the Mitochondrial Genomes of Nilaparvata (Hemiptera: Delphacidae).

Planthoppers in the genus Nilaparvata Distant are serious pests of rice and many other crops in tropical and temperate Asia, and northern Australia. In this study, the mitochondrial genomes of four Nilaparvata planthoppers were sequenced, three in Nilaparvata lugens Stål and one in Nilaparvata muiri China. Mitochondrial genome of Nilaparvata contain the standard set of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region. The nucleotide composition of Nilaparvata mitochondrial sequence is biased toward adenine and thymine, and the amino acid composition is affected to a similar degree by the bias to AT. We compare the four mitochondrial genomes and find intra- and interspecific variation in gene length, base composition, nucleotide and amino acid substitutions, intergenic spacer length, and gene overlap. The intra- and interspecific variations reveal that nucleotide and amino acid substitutions in mitochondrial protein-coding genes make a contribution to the formation of various insect biotypes in one species. Furthermore, the accumulation of nonsynonymous substitutions in the mitochondrial protein-coding genes, as well as differences in start codons, the length of intergenic spacers, and gene overlap regions contribute to differences between the two species investigated here. In addition, cox is the most conserved gene family and nad4-nad4l cluster is variable in Nilaparvata mitochondrial genes for the intra- and interspecific variation.

Identification and characterization of Bph14, a gene conferring resistance to brown planthopper in rice.

Planthoppers are highly destructive pests in crop production worldwide. Brown planthopper (BPH) causes the most serious damage of the rice crop globally among all rice pests. Growing resistant varieties is the most effective and environment-friendly strategy for protecting the crop from BPH. More than 19 BPH-resistance genes have been reported and used to various extents in rice breeding and production. In this study, we cloned Bph14, a gene conferring resistance to BPH at seedling and maturity stages of the rice plant, using a map-base cloning approach. We show that Bph14 encodes a coiled-coil, nucleotide-binding, and leucine-rich repeat (CC-NB-LRR) protein. Sequence comparison indicates that Bph14 carries a unique LRR domain that might function in recognition of the BPH insect invasion and activating the defense response. Bph14 is predominantly expressed in vascular bundles, the site of BPH feeding. Expression of Bph14 activates the salicylic acid signaling pathway and induces callose deposition in phloem cells and trypsin inhibitor production after planthopper infestation, thus reducing the feeding, growth rate, and longevity of the BPH insects. Our work provides insights into the molecular mechanisms of rice defense against insects and facilitates the development of resistant varieties to control this devastating insect.

Isolation and characterization of microsatellite markers in brown planthopper (Nilaparvata lugens Stål).

Brown planthopper (Nilaparvata lugens Stål) (Homoptera: Delphacidae) is an economically important pest on rice. In this study, 30 polymorphic microsatellite markers were developed from N. lugens genomic libraries using the method of Fast Isolation by AFLP of Sequence Containing Repeats (FIASCO). Polymorphism of each locus was detected in 48 individuals from two natural populations. These microsatellite loci revealed 2 to 18 alleles, and the expected and observed heterozygosities ranged from 0.042 to 0.937 and from 0.042 to 0.958, respectively. These markers will be useful for the future study of this agricultural pest in population genetics and molecular genetics.

Luteolin induces mitochondrial apoptosis in HT29 cells by inhibiting the Nrf2/ARE signaling pathway.

The aim of the current study was to investigate luteolin-induced apoptosis and the molecular mechanisms underlying it in HT29 cells. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to assess the cytotoxicity of luteolin on HT29 cells, and a dichloro-dihydro-fluorescein diacetate assay was used to measure cellular levels of reactive oxygen species (ROS). The effects of luteolin on the mitochondrial membrane potential were also evaluated. Bax and Bcl-2 mRNA expression were determined using reverse transcription-quantitative PCR. Additionally, western blot analysis was performed to assess changes in cytochrome c and caspase-3 protein expression. Localization of nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus was also assessed using immunofluorescence. Luteolin exhibited cytotoxicity on HT29 cells in a time- and concentration-dependent manner. Additionally, ROS production was indicated to be increased and ROS scavenging was decreased, which resulted in a significant increase in the levels of ROS in the cells. The mitochondrial membrane potential was indicated to decrease following luteolin treatment. At the molecular level, luteolin significantly increased the mRNA expression of Bax and the protein expression of cytochrome c, caspase-3, p47phox and p22phox. The results revealed that luteolin decreased Bcl-2 protein expression and inhibited the nuclear localization of Nrf2. In conclusion, the current study indicated that luteolin inhibited HT29 cell proliferation and induced apoptosis via the mitochondrial pathway.

Development of an artificial neuronal network with post-mitotic rat fetal hippocampal cells by polyethylenimine.

The selection of appropriate surface materials that promote cellular adhesion and growth is an important consideration when designing a simplified neuronal network in vitro. In the past, extracellular matrix proteins such as laminin (LN) or positively charged substances such as poly-l-lysine (PLL) have been used. In this study, we examined the ability of another positively charged polymer, polyethyleneimine (PEI), to promote neuronal adhesion, growth and the formation of a functional neuronal network in vitro. PEI, PLL and LN were used to produce grid-shape patterns on glass coverslips by micro-contact printing. Post-mitotic neurons from the rat fetal hippocampus were cultured on the different polymers and the viability and morphology of these neurons under serum-free culture conditions were observed using fluorescent microscopy and atomic force microscopy (AFM). We show that neurons cultured on the PEI- and PLL-coated surfaces adhered to and extended neurites along the grid-shape patterns, whereas neurons cultured on the LN-coated coverslips clustered into clumps of cells. In addition, we found that the neurons on the PEI and PLL-coated grids survived for more than 2 weeks in serum-free conditions, whereas most neurons cultured on the LN-coated grids died after 1 week. Using AFM, we observed some neurosynapse-like structures near the neuronal soma on PEI-coated coverslips. These findings indicate that PEI is a suitable surface for establishing a functional neuronal network in vitro.

Layer-by-layer assembly of polyelectrolyte films improving cytocompatibility to neural cells.

The using of layer-by-layer assembly polyelectrolyte (PE) films has been suggested as a new versatile technique for surface modification aimed at tissue engineering and cell-based chips. In this study, we investigated the surface morphology of the hyaluronic acid (HA)-based PE films deposited on the amino-functionalized glass slides using atomic force microscopy. These thin films (bilayer number <9) were measured to have nanoscale roughness ranging from 10 to 100 nm. Then the primary hippocampal and cortical neural cells were cultured on the PE films, respectively. After 5 days of culturing, the cytocompatibility to neural cells was evaluated by cellular morphology, neurite outgrowth, and microtubule-associated protein 2 expressions. From the present results, the HA-based PE films were found to be able to support neural cell adhesion and neurite development, especially for the polycation-ending films. It is suggested these HA-based multilayer PE films or similar build-ups could thus be used in the future as a way to modify surfaces for nerve scaffolds and neuron-based chips.

Maternal Brain TNF-α Programs Innate Fear in the Offspring.

Tumor necrosis factor alpha (TNF-α) is a cytokine that not only coordinates local and systemic immune responses [1, 2] but also regulates neuronal functions. Most prominently, glia-derived TNF-α has been shown to regulate homeostatic synaptic scaling [3-6], but TNF-α-null mice exhibited no apparent cognitive or emotional abnormalities. Instead, we found a TNF-α-dependent intergenerational effect, as mothers with a deficit in TNF-α programmed their offspring to exhibit low innate fear. Cross-fostering and conditional knockout experiments indicated that a TNF-α deficit in the maternal brain, rather than in the hematopoietic system, and during gestation was responsible for the low-fear offspring phenotype. The level of innate fear governs the balance between exploration/foraging and avoidance of predators and is thus fundamentally important in adaptation, fitness, and survival [7]. Because maternal exercise and activity are known to reduce both brain TNF-α [8] and offspring innate fear [9], whereas maternal stress has been reported to increase brain TNF-α [10] and offspring fear and anxiety [11, 12], maternal brain TNF-α may report environmental conditions to promote offspring behavioral adaptation to their anticipated postnatal environment.

Behavioural traits propagate across generations via segregated iterative-somatic and gametic epigenetic mechanisms.

Parental behavioural traits can be transmitted by non-genetic mechanisms to the offspring. Although trait transmission via sperm has been extensively researched, epidemiological studies indicate the exclusive/prominent maternal transmission of many non-genetic traits. Since maternal conditions impact the offspring during gametogenesis and through fetal/early-postnatal life, the resultant phenotype is likely the aggregate of consecutive germline and somatic effects; a concept that has not been previously studied. Here, we dissected a complex maternally transmitted phenotype, reminiscent of comorbid generalized anxiety/depression, to elementary behaviours/domains and their transmission mechanisms in mice. We show that four anxiety/stress-reactive traits are transmitted via independent iterative-somatic and gametic epigenetic mechanisms across multiple generations. Somatic/gametic transmission alters DNA methylation at enhancers within synaptic genes whose functions can be linked to the behavioural traits. Traits have generation-dependent penetrance and sex specificity resulting in pleiotropy. A transmission-pathway-based concept can refine current inheritance models of psychiatric diseases and facilitate the development of better animal models and new therapeutic approaches.

Maternal hematopoietic TNF, via milk chemokines, programs hippocampal development and memory.

Tumor necrosis factor α (TNF) is a proinflammatory cytokine with established roles in host defense and immune system organogenesis. We studied TNF function and found a previously unidentified physiological function that extends its effect beyond the host into the developing offspring. A partial or complete maternal TNF deficit, specifically in hematopoietic cells, resulted in reduced milk levels of the chemokines IP-10, MCP-1, MCP-3, MCP-5 and MIP-1ß, which in turn augmented offspring postnatal hippocampal proliferation, leading to improved adult spatial memory in mice. These effects were reproduced by the postpartum administration of a clinically used anti-TNF agent. Chemokines, fed to suckling pups of TNF-deficient mothers, restored both postnatal proliferation and spatial memory to normal levels. Our results identify a TNF-dependent 'lactrocrine' pathway that programs offspring hippocampal development and memory. The level of ambient TNF is known to be downregulated by physical activity, exercise and adaptive stress. We propose that the maternal TNF-milk chemokine pathway evolved to promote offspring adaptation to post-weaning environmental challenges and competition.

Genome-wide mapping of virulence in brown planthopper identifies loci that break down host plant resistance.

Insects and plants have coexisted for over 350 million years and their interactions have affected ecosystems and agricultural practices worldwide. Variation in herbivorous insects' virulence to circumvent host resistance has been extensively documented. However, despite decades of investigation, the genetic foundations of virulence are currently unknown. The brown planthopper (Nilaparvata lugens) is the most destructive rice (Oryza sativa) pest in the world. The identification of the resistance gene Bph1 and its introduction in commercial rice varieties prompted the emergence of a new virulent brown planthopper biotype that was able to break the resistance conferred by Bph1. In this study, we aimed to construct a high density linkage map for the brown planthopper and identify the loci responsible for its virulence in order to determine their genetic architecture. Based on genotyping data for hundreds of molecular markers in three mapping populations, we constructed the most comprehensive linkage map available for this species, covering 96.6% of its genome. Fifteen chromosomes were anchored with 124 gene-specific markers. Using genome-wide scanning and interval mapping, the Qhp7 locus that governs preference for Bph1 plants was mapped to a 0.1 cM region of chromosome 7. In addition, two major QTLs that govern the rate of insect growth on resistant rice plants were identified on chromosomes 5 (Qgr5) and 14 (Qgr14). This is the first study to successfully locate virulence in the genome of this important agricultural insect by marker-based genetic mapping. Our results show that the virulence which overcomes the resistance conferred by Bph1 is controlled by a few major genes and that the components of virulence originate from independent genetic characters. The isolation of these loci will enable the elucidation of the molecular mechanisms underpinning the rice-brown planthopper interaction and facilitate the development of durable approaches for controlling this most destructive agricultural insect.

Permanent genetic resources added to Molecular Ecology Resources Database 1 December 2011-31 January 2012.

This article documents the addition of 473 microsatellite marker loci and 71 pairs of single-nucleotide polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Barteria fistulosa, Bombus morio, Galaxias platei, Hematodinium perezi, Macrocentrus cingulum Brischke (a.k.a. M. abdominalis Fab., M. grandii Goidanich or M. gifuensis Ashmead), Micropogonias furnieri, Nerita melanotragus, Nilaparvata lugens Stål, Sciaenops ocellatus, Scomber scombrus, Spodoptera frugiperda and Turdus lherminieri. These loci were cross-tested on the following species: Barteria dewevrei, Barteria nigritana, Barteria solida, Cynoscion acoupa, Cynoscion jamaicensis, Cynoscion leiarchus, Cynoscion nebulosus, Cynoscion striatus, Cynoscion virescens, Macrodon ancylodon, Menticirrhus americanus, Nilaparvata muiri and Umbrina canosai. This article also documents the addition of 116 sequencing primer pairs for Dicentrarchus labrax.

Hyaluronic acid hydrogel modified with nogo-66 receptor antibody and poly-L-lysine to promote axon regrowth after spinal cord injury.

The biomaterials used for central nervous system injury require not only interacting with specific cell adhesion but also specific growth factor receptors to promote nerve regeneration. In this study, hyaluronic acid (HA)-based hydrogels modified with poly-L-lysine (PLL) and nogo-66 receptor antibody (antiNgR) (HA-PLL/antiNgR) were administered to rats after lateral hemisection of the spinal cord. Anti-neurofilament positive axons were found to extend into the HA-PLL/antiNgR hydrogel at 8 weeks after implantation, which shows significant difference compared with HA-PLL or blank control group. Electron micrographs of implanted hydrogels showed that there were more cells and normal axons with myelin in the HA-PLL/antiNgR implant than that of HA-PLL hydrogel. The antiNgR grafted on HA hydrogels could be detected for 8 weeks after transplantation in vivo. All of these properties may facilitate HA-PLL/antiNgR hydrogels to become a promising scaffold for repairing spinal cord injury. Nevertheless, both two kinds of modified hydrogels (HA-PLL/antiNgR and HA-PLL) showed remarkable advantages in supporting angiogenesis, and simultaneously inhibiting the formation of glial scar.

Preparation and characterization of fibroin/hyaluronic acid composite scaffold.

Hyaluronic acid (HA) was added into fibroin solution to prepare fibroin-based porous composite scaffolds. HA exhibited important effects on pore formation and hydrophilicity of fibroin-based scaffold. The aqueous-fibroin/HA scaffolds had highly homogeneous and interconnected pores with porosity of above 90% and controllable pore size ranging from 123 to 253 microm. The water take-up of fibroin/HA scaffolds increased significantly with the increase of HA content. Containing HA at a defined content range, such as 3-6%, fibroin-based scaffolds' affinity to primary neural cells was improved. In 6%HA/fibroin scaffolds, neurosphere-forming cell migrated from their original aggregate and adhered tightly to the surface of scaffolds.