Search

The white-backed planthopper, Sogatella furcifera (Horváth), causes substantial damage to crops by direct feeding or virus transmission, especially southern rice black-streaked dwarf virus, which poses a serious threat to rice production. Cycloxaprid, a novel cis-nitromethylene neonicotinoid insecticide, has high efficacy against rice planthoppers, including imidacloprid-resistant populations. However, information about the influence of cycloxaprid on S. furcifera (Hemiptera: Delphacidae) at the molecular level is limited. Here, by de novo transcriptome sequencing and assembly, we constructed two transcriptomes of S. furcifera and profiled the changes in gene expression in response to cycloxaprid at the transcription level. We identified 157,906,456 nucleotides and 131,601 unigenes using the Illumina technology from cycloxaprid-treated and untreated S. furcifera. In total, 38,534 unigenes matched known proteins in at least one database, accounting for 29.28% of the total unigenes. The number of coding DNA sequences was 28,546 and that of amino acid sequences in the coding region was 22,299. In total, 15,868 simple sequence repeats (SSRs) were identified. The trinucleotide repeats accounted for 45.1% (7,157) of the total SSRs and (AAG/CTT)n were the most frequent motif. There were 359 differentially expressed genes that might have been induced by cycloxaprid. There were 131 upregulated and 228 downregulated genes. Twenty-two unigenes might be involved in resistance against cycloxaprid, such as cytochrome P450, glutathione S-transferase (GST), acid phosphatase (ACP), and cadherin. Our study provides vital information on cycloxaprid-induced resistance mechanisms, which will be useful to analyze the molecular mechanisms of cycloxaprid resistance and may lead to the development of novel strategies to manage S. furcifera.

With the expansion of distance education, the problem of over-education in the system of distance education has emerged, but it seems that none of the existing empirical studies have addressed this issue. This study conducts an empirical and comparative analysis of the problem of over-education between distance education and face-to-face education by analyzing nationwide adult data in China. The empirical results show that distance-education learners are more likely to experience over-education compared to face-to-face education learners; however, over-education does not have a significantly negative relationship with distance-education learners’ income.

Background The insect predator Coccinella septempunctata can effectively control many types of pests, such as aphids, whiteflies, and small lepidopteran larvae. We previously found that C. septempunctata fed an artificial diet showed diminished biological properties(e.g. fecundity, egg hatching rate, survival rate, etc.) compared with those fed natural prey (Aphis craccivora), likely due to different nutritional characteristics of the diet. In this study, we used transcriptome sequencing analysis to identify nutrition- and metabolism-related genes of C. septempunctata that were differentially expressed depending on diet. Methodology/principal findings The Illumina HiSeq2000 was used to sequence 691,942,058 total clean reads from artificial diet-fed and A. craccivora-fed C. septempunctata libraries, and the clean reads were assembled using Trinity de novo software (Tabel 2). Comparison of transcriptome sequences revealed that expression of 38,315 genes was affected by the artificial diet, and 1,182 of these genes showed a significant change in expression levels (FDR ≤ 0.05,|log2FC|≥1, "FC" stands for "fold change"). These differentially expressed genes (DEGs) were likely associated with the decreased egg laying capacity, hatching rate, longevity, and increased sex ratio (♀:♂) of adult C. septempunctata observed in the group fed the artificial diet. Furthermore, in the most DEGs metabolic pathways for C. septempunctata feeding on the artificial diet accumulated amino acid metabolic pathways, lipid metabolic pathways, and starch and glucose metabolism were down-regulated. Conclusions/significance We found some differentially expressed genes and metabolic pathways are related to nutrition, from which a more informative feedback for diet formulation was obtained and the artificial diet could be more efficiently optimized.

An artificial diet was developed for continuous maintenance of ladybird beetle (Coccinella septempunctata) adults. This beetle is an important biocontrol agent for greenhouse crops. Several biological parameters were measured and compared between colonies fed the artificial diet over eight successive generations, and colonies fed aphids. Weight, survival rates from 1st to 4th instar, pupation rate, and emergence rate were similar for both colonies, but the sex ratio (♀:♂) of the artificial diet-fed colony was higher than that of the aphid-fed colony. These results suggest that this artificial diet could meet the basic needs for the successive rearing of C. septempunctata adults. The prepared diet, which is semi-solid, provides suitable moisture for C. septempunctata, and the diet ingredients are inexpensive and relatively easy to prepare. This diet and rearing technique offers a very useful approach for mass production of C. septempunctata.

As a newer cis-nitromethylene neonicotinoid pesticide at present, cycloxaprid has good industrialization prospects, including the management of imidacloprid-resistant populations, because this chemical have an excellent efficiency against rice planthoppers. Sogatella furcifera (Horváth) is the most economically important pest of rice worldwide and has developed resistance to many insecticides. This study focused on the expression change of these resistance genes, induced by cycloxaprid, involved in metabolic detoxification and receptor protein. Twenty-two differentially expressed genes (DEGs) that may be related with the insecticide resistance were found in the transcriptome of S. furcifera, including 2 cytochrome P450 genes, 2 glutathione S-transferase (GST) genes, 1 acid phosphatase (ACP) gene, 12 decarboxylase genes, 2 glycolipid genes, 1 cadherin gene, and 2 glycosyltransferase genes, which were up- or downregulated in response to an exposure of cycloxaprid. Furthermore, two P450 genes (CYP4 and CYP6 family, respectively), two decarboxylase genes, and one glycosyltransferase gene were validated by qRT-PCR. Expression differences of these genes verified successfully by qRT-PCR in response to different concentrations and times treated with cycloxaprid could explain the insecticide resistance mechanism under cycloxaprid stress in S. furcifera.

Gut bacteria play a significant role in host insect. This study evaluated detail difference of midgut bacteria in deltamethrin-resistant, deltamethrin-susceptible and field-caught populations of diamondback moth, and studied phenomics of the predominant midgut bacterium Enterococcus mundtii. Cultivable bacteria revealed that E. mundtii and Carnobacterium maltaromaticum dominated the bacterial populations from deltamethrin-resistant and deltamethrin-susceptible larval midguts, whereas E. mundtii was predominant in field-caught population. Illumina sequencing analysis indicated that 97% of the midgut bacteria were from the phyla Firmicutes, Proteobacteria and Cyanobacteria. Both resistant and susceptible populations had more Enterococcus and Carnobacterium. Enterococcus, Carnobacterium, Bacillus, and Pseudomonas were predominant in the field-caught population. A phenomics analysis revealed that E. mundtii was able to metabolize 25.26% of the tested carbon sources, 100% of the nitrogen sources, 100% of the phosphorus sources and 97.14% of the sulfur sources, had a wide range of osmolytes and pH conditions, and showed active deaminase activity but no decarboxylase activity. This is the first report regarding different populations of DBM midgut bacteria analyzed using both high-throughput DNA sequencing and cultivation methods, and also first report concerning the phenomics of E. mundtii. The phenomics of E. mundtii provide a basis for the future study of gut bacteria functions.

Sogatella furcifera (Horváth) is a migratory insect that is one of the most important pest species on rice in many Asian countries. Control of S. furcifera (Hemiptera: Delphacidae) primarily depends on the use of chemical insecticides, and with this extensive reliance on pesticides, determining the degree of resistance of S. furcifera populations to the chemicals used for its control is essential. In this study, the resistance level to six conventional insecticides in five populations of S. furcifera from Guizhou Province was monitored yearly using the rice-stem dipping method in 2012–2015 to precisely understand current resistance levels and to estimate trends in the development of insecticide resistance in S. furcifera in Guizhou. Overall, S. furcifera from five regions in Guizhou showed a trend toward decreased susceptibility to isoprocarb (resistance ratio [RR] 0.82–3.59), susceptibility to low resistance against thiamethoxam (RR 0.27–9.69), susceptibility to moderate resistance to imidacloprid (RR 0.71–26.06), and decreased susceptibility to moderate resistance to chlorpyrifos (RR 4.63–19.58). The resistance to pymetrozine (RR 10.48–84.65) was moderate to high, and that to buprofezin (RR 6.36–412.43) was low to very high. In conclusion, the use of buprofezin and pymetrozine to control S. furcifera should be reduced in Guizhou Province, whereas prudent use at a reasonable frequency of chlorpyrifos and imidacloprid can continue. Isoprocarb and thiamethoxam are the best choices for effective management of S. furcifera. Rotations using alternative insecticides with different modes of action are recommended for regions in which resistance is at a moderate level.

Gut bacterium Pantoea sp. is one of the predominant bacterial species in the larval gut of the diamondback moth, Plutella xylostella. The phenotypic characters of Pantoea sp. were investigated with BIOLOG phenotype MicroArray (PM) in this study. Totally 950 different metabolic phenotypes were tested using the PM plates 1–10. Results exhibited that Pantoea sp. was able to metabolize 37.37 % of the tested carbon sources, 91.32 % of nitrogen sources, 100 % of sulfur sources, and 98.31 % of phosphorus sources. Most informative utilization patterns for carbon sources of Pantoea sp. were organic acids and carbohydrates, and for nitrogen were various amino acids. The bacterium had 94 different biosynthetic pathways. It had a wide range of adaptabilities, and could still metabolize in osmolytes with up to 9 % sodium chloride, 6 % potassium chloride, 5 % sodium sulfate, 20 % ethylene glycol, 4 % sodium formate, 4 % urea, 5 % sodium lactate, 200 mmol/L sodium phosphate (pH 7.0), 100 mmol/L ammonium sulfate (pH 8.0), 100 mmol/L sodium nitrate, and 100 mmol/L sodium nitrite, respectively. It also exhibited active metabolism under pH values between 4.5 and 10. Pantoea sp. showed active decarboxylase activities while poor deaminase activities in the presence of various amino acids. The phenotypic characterization of Pantoea sp. increased our knowledge of the bacterium, in particular its interactions with insect hosts and the adaptability in gut environments, and showed us some possible approaches to controlling diamondback moth through decreasing Pantoea sp. density.

Burton Clark (1983) argued that variation in higher education was mainly affected by the combination of three forces: state authority, the market, and the academic oligarchy, thus establishing a ‘t...

Background The white backed planthopper, Sogatella furcifera (Horváth), causes substantial damage to many crops by direct feeding or transmitting plant viruses, especially southern rice black-streaked dwarf virus (SRBSDV) that has become a great threat to rice production in East Asia. Cycloxaprid, a novel cis-nitromethylene neonicotinoid insecticide, has good industrialization prospects because of its high efficiency against rice planthoppers, including imidacloprid-resistant populations. This chemical would be used extensively in future. However, very little is known about the influence on S. furcifera after cycloxaprid application at the molecular level. We sequenced S. furcifera transcriptome of female adult of S. furcifera using the Illumina sequencing. Results By de novo transcriptome assembling and massive parallel pyrosequencing, we constructed two transcriptomes of S. furcifera and profiled the alternation of gene expression in response to cycloxaprid treatment in transcriptional level. Over 157,906,456 nucleotides and 131,601 different unigenes were generated using Illumina technology from both cycloxaprid-treatment and no-treatment S. furcifera. And a total of 38,534 unigenes matched known proteins in at least one database, accounting for 29.28% in total unigenes. The number of Coding DNA Sequence (CDS) were 28,546 and that of the amino acid sequence of coding region were 22,299. A total 15,868 simple sequence repeats (SSRs) were identified. The trinucleotide repeats accounted for 45.1% (7,157) in total SSRs and the (AAG/CTT)n was the most frequent motif. There were 359 differentially expressed genes (DEGs) that might be induced by cycloxaprid. There were 131 genes up-regulated and 228 down-regulated. 22 unigenes may take participate in the resistance to cycloxaprid, such as cytochrome P450, Glutathione-s transferase (GST), Acid phosphatase (ACP), cadherin, etc. Conclusions Our study will provide a splendid database for future investigations of the resistance mechanism induced by cycloxaprid and will provide new strategies for pest management and crop protection.