preference-assessment-of-white-backed-planthopper-feeding-on-rice

Preference Assessment of White-backed Planthopper Feeding on Rice

Exploiting insect-resistant rice germplasm resources and related genes is the primary need for breeding insect-resistant varieties, but the accuracy of ...

Chinese Academy of Agricultural Sciences

Nipah virus (NiV), a member of the Paramyxoviridae family, causes deadly encephalitis in humans and huge economic losses to the pig industry. Here, we generated recombinant avirulent Newcastle disease virus (NDV) LaSota strains expressing the NiV G and F proteins respectively (designated as rLa-NiVG and rLa-NiVF), and evaluated their immunogenicity in mice and pigs. Both rLa-NiVG and rLa-NiVF displayed growth properties similar to those of LaSota virus in chicken eggs. Co-infection of rLa-NiVG and rLa-NiVF caused marked syncytia formation, while intracerebral co-inoculation of these viruses in mice showed they were safe in at least one mammalian species. Animal immunization studies showed rLa-NiVG and rLa-NiVF induced NiV neutralizing antibody responses in mice and pigs, and F protein-specific CD8+ T cell responses in mice. Most importantly, rLa-NiVG and rLa-NiVF administered alone or together, induced a long-lasting neutralizing antibody response in pigs. Recombinant rLa-NiVG/F thus appear to be promising NiV vaccine candidates for pigs and potentially humans.

Newcastle disease virus-vectored Nipah encephalitis vaccines induce B and T cell responses in mice and long-lasting neutralizing antibodies in pigs.

Take-all, which is caused by the fungal pathogen, Gaeumannomyces graminis var. tritici (Ggt), is an important soil-borne root rot disease of wheat occurring worldwide. However, the genetic basis of Ggt pathogenicity remains unclear. In this study, transcriptome sequencing for Ggt in axenic culture and Ggt-infected wheat roots was performed using Illumina paired-end sequencing. Approximately 2.62 and 7.76 Gb of clean reads were obtained, and 87% and 63% of the total reads were mapped to the Ggt genome for RNA extracted from Ggt in culture and infected roots, respectively. A total of 3,258 differentially expressed genes (DEGs) were identified with 2,107 (65%) being 2-fold up-regulated and 1,151 (35%) being 2-fold down-regulated between Ggt in culture and Ggt in infected wheat roots. Annotation of these DEGs revealed that many were associated with possible Ggt pathogenicity factors, such as genes for guanine nucleotide-binding protein alpha-2 subunit, cellulase, pectinase, xylanase, glucosidase, aspartic protease and gentisate 1, 2-dioxygenase. Twelve DEGs were analyzed for expression by qRT-PCR, and could be generally divided into those with high expression only early in infection, only late in infection and those that gradually increasing expression over time as root rot developed. This indicates that these possible pathogenicity factors may play roles during different stages of the interaction, such as signaling, plant cell wall degradation and responses to plant defense compounds. This is the first study to compare the transcriptomes of Ggt growing saprophytically in axenic cultures to it growing parasitically in infected wheat roots. As a result, new candidate pathogenicity factors have been identified, which can be further examined by gene knock-outs and other methods to assess their true role in the ability of Ggt to infect roots. 

Comparative transcriptome profiling of the early infection of wheat roots by Gaeumannomyces graminis var. tritici.

We established two Madin-Darby canine kidney (MDCK) cell lines stably expressing human airway transmembrane protease: transmembrane protease, serine 2 (TMPRSS2) and mosaic serine protease large form (MSPL) which support multicycle growth of two H5 highly pathogenic avian influenza viruses (HPAIV) recombinant vaccines (Re-5 and Re-6) and an H9 avian influenza virus (AIV) recombinant vaccine (Re-9) in the absence of trypsin. Data showed that the cell lines stably expressed TMPRSS2 and MSPL after 20 serial passages. Both MDCK-TMPRSS2 and MDCK-MSPL could proteolytically cleave the HA of Re-5, Re-6, and Re-9 and supported high-titer growth of the vaccine without exogenous trypsin. Re-5, Re-6, and Re-9 efficiently infected and replicated within MDCK-TMPRSS2 and MDCK-MSPL cells and viral titer were comparable to the virus grown in MDCK cells with TPCK-trypsin. Thus, our results indicate a potential application for these cell lines in cell-based influenza vaccine production and may serve as a useful tool for HA proteolytic cleavage-related studies. 

Establishment of MDCK Stable Cell Lines Expressing TMPRSS2 and MSPL and Their Applications in Propagating Influenza Vaccine Viruses in Absence of Exogenous Trypsin.

Crop resistance is a cost-effective and environmentally friendly strategy for pest management. The brown planthopper (BPH, Nilaparvata lugens) is a devastating rice insect pest due to its ability to rapidly overcome plant resistance and the lack of sufficient resistance resources. BR4831 (a rice breeding line derived from the pyramiding of two BPH resistance genes, Bph14 and Bph15, into the elite rice variety Huang-Hua-Zhan, HHZ) and two single-gene introgression lines (HF106, carrying Bph14, and C602, carrying Bph15, in the elite rice cultivar 9311) were evaluated for their resistance to BPH using a standard seed box screening test coupled with field tests. The related resistance types were determined using laboratory assays. The seed box test and laboratory biological assays showed that BR4831 exhibited strong antibiotic resistance, and the behavioral assay showed that this line also exhibited strong antixenotic resistance, while both HF106 and C602 exhibited only weak antibiosis and no antixenotic resistance. Field tests showed significantly improved resistance in BR4831 compared to that of its recipient parent HHZ and slightly increased resistance in HF106 and C602 in comparison with their recipient parent 9311. These results demonstrate that the rice line BR4831, with pyramided resistance genes, exhibits higher resistance than the monogenic lines HF106 and C602 and highlight the benefits of combining the seed box seedling test, field tests and laboratory assays to thoroughly analyze plant resistance types.

Resistance to Nilaparvata lugens in rice lines introgressed with the resistance genes Bph14 and Bph15 and related resistance types.

ATP-binding cassette (ABC) transporters, a large class of transmembrane proteins, are widely found in organisms and play an important role in the transport of xenobiotics. Insect ABC transporters are involved in insecticide detoxification and  (Bt) toxin perforation. The complete ABC transporter is composed of two hydrophobic transmembrane domains (TMDs) and two nucleotide binding domains (NBDs). Conformational changes that are needed for their action are mediated by ATP hydrolysis. According to the similarity among their sequences and organization of conserved ATP-binding cassette domains, insect ABC transporters have been divided into eight subfamilies (ABCA-ABCH). This review describes the functions and mechanisms of ABC transporters in insecticide detoxification, plant toxic secondary metabolites transport and insecticidal activity of Bt toxin. With improved understanding of the role and mechanisms of ABC transporter in resistance to insecticides and Bt toxins, we can identify valuable target sites for developing new strategies to control pests and manage resistance and achieve green pest control.

Insect ATP-Binding Cassette (ABC) Transporters: Roles in Xenobiotic Detoxification and Bt Insecticidal Activity.

Pinocembrin (PIN) is a natural flavonoid widely found in bee propolis with potent gastrointestinal protective effects. In consequence, PIN has great potential in preventing inflammatory bowel diseases (IBDs) while scant information is available. In this study, a dextran sulfate sodium (DSS)-induced rats ulcerative colitis model (3.5% DSS in drinking water for 7 days) was applied to explore the protective effects of PIN on macroscopic colitis symptoms, inflammation, intestinal epithelial barrier function, and gut microbiota homeostasis. While DSS-treated rats showed severe colitis clinical symptoms and histological changes (colonic pathological damages and intestinal goblet cells loss), pre-administration of PIN (5 and 10 mg/kg, ) for a week alleviated these symptoms. Pre-administration of PIN also suppressed the pro-inflammatory gene expressions and improved tight junction functions of colonic epithelial cells. Additionally, PIN administration reversed DSS-induced short chain fatty acid loss, and improved the gut microbial diversity assessed by 16S rRNA phylogenetic sequencing. Overall, our results suggest a wide spectrum of protective effects of PIN in preventing IBDs.

Pinocembrin Protects Against Dextran Sulfate Sodium-Induced Rats Colitis by Ameliorating Inflammation, Improving Barrier Function and Modulating Gut Microbiota.

Vip3A proteins are widely used for controlling pest Lepidoptera. Different binding sites with different receptors in the insect midgut membrane and lack of cross-resistance with crystal (Cry) proteins enhance their applicability, as both single proteins and proteins pyramided with Cry proteins in transgenic Bt crops. Vip3A proteins are effective but there is relatively little information about their structure, function, activation, specificity, and mode of action. In addition, the mechanism of insect resistance to these proteins is unknown. Phylogenetic analysis and multiple sequence alignment showed that Vip3A proteins are genetically distant from Cry proteins. The mode of action and insecticidal activity of Vip3A proteins are discussed in this review. This review also provides detailed information about the Vip3A protein family that may aid in the design of more efficient pest management strategies in response to insect resistance to insecticidal proteins. © 2020 Society of Chemical Industry.

Chao Wu

Agricultural Genomics Institute at Shenzhen

Chinese Academy of Agricultural Sciences

Preference Assessment of White-backed Planthopper Feeding on Rice