摘要：
The xenobiotic transcription factor cap 'n' collar isoform C (CncC) is considered the central regulator of antioxidant and detoxification genes. Previous research indicated that CncC regulates three-phase enzymes responsible for insecticide resistance. In this study, the SlituCncC gene from Spodoptera litura was obtained and characterized. Quantitative PCR (qPCR) analysis showed that SlituCncC was expressed in all developmental stages and tissues, but was highly expressed in third- and fourth-instar larvae, and in the Malpighian tubule, fat body, and midgut. In addition, SlituCncC was up-regulated and more highly induced with indoxacarb treatment in the indoxacarb-resistant strains compared with the susceptible strain. RNA interference-mediated gene silencing of SlituCncC significantly increased mortality of S.litura when exposed to indoxacarb. Furthermore, comparative transcriptome analysis showed that 842 genes were down-regulated and 127 genes were up-regulated in SlituCncC-knockdown S. litura. Further analysis indicated that 18 three-phase enzymes were identified in the down-regulated genes, of which seven were associated with indoxacarb resistance in S. litura. qPCR analysis confirmed that expression of six of these seven genes was consistent with RNA sequencing data. All six detoxification genes were induced by indoxacarb, and the expression patterns were similar to that of SlituCncC. Finally, the CncC-Maf binding site was predicted in all six gene promoters. This study indicates that the transcription factor SlituCncC may regulate multiple detoxification genes that mediate indoxacarb resistance in S. litura. This article is protected by copyright. All rights reserved.
摘要：
BACKGROUND Carboxylesterases (CarEs) are important in pesticide resistance. Four overexpressed CarE genes with inducible character were screened out in fenpropathrin-resistant Tetranychus cinnabarinus, but their functional roles remained to be further analyzed by RNAi and protein expression. RESULTS CONCLUSION Feeding a single double-stranded (ds)RNA of each of four genes led to gene-specific downregulation of mRNA, decreased esterase activity and diminished resistance in T. cinnabarinus. More interestingly, feeding four dsRNAs simultaneously led to a more significant decrease in enzymatic activity and fold resistance than feeding a single dsRNA individually, suggesting that these CarE genes were involved in fenpropathrin-resistance and had cooperative roles. The gene CarE6 was regarded as the primary and representative candidate to be functionally expressed, because silencing of CarE6 led to the most significant decrease in resistance level. The activity of CarE6 protein was competitively inhibited by fenpropathrin. It could effectively decompose 41.7 +/- 0.09% of fenpropathrin within 3 h, proving that CarE6 protein was capable of metabolizing fenpropathrin effectively in T. cinnabarinus. The results confirm that four CarE genes are cooperatively involved in fenpropathrin resistance and the metabolic enzymes encoded by these overexpressed genes do indeed metabolize acaricide in resistant T. cinnabarinus in the evolution of acaricide resistance. (c) 2018 Society of Chemical Industry
通讯机构：
[Liu, SQ; Liao, XL; Liu, Shuangqing; Liao, Xiaolan] H;Hunan Agr Univ, Coll Plant Protect, Changsha, Hunan, Peoples R China.;Hunan Prov Key Lab Biol & Control Plant Dis & Pla, Changsha, Hunan, Peoples R China.;Hunan Biol Pesticides & Pesticide Preparat Proc E, Changsha, Hunan, Peoples R China.
关键词：
Active components;Antagonistic bacteria;Botrytis cinerea;Control effect;Identification
摘要：
To resolve the problem of pesticide resistance in strawberry gray mold Botrytis cinerea and to improve the effectiveness of disease preventive measures by developing biological pesticides, a bacterial strain was identified using plate confrontation culture method, morphological characteristics, physiological and biochemical analyses, and 16S rDNA gene sequence analysis. The antifungal components of the antagonistic bacterial strain were analyzed by GC-MS, and their in vitro control effects were evaluated. One hundred bacterial strains were isolated from the strawberry rhizosphere soil, of which one showed superior antagonistic effect, accounting for 1% of all of the strains, and it was designated as strain ZY86. Further investigation indicated that strain ZY86 exhibited antifungal effects not only against B. cinerea but also against Rhizoctonia solani, Magnaporthe grisea, Colletotrichum capsici, Phytophthora capsici and Sclerotinia sclerotiorum. Strain ZY86 (GenBank Accession number MK111627) was highly similar to model strain Acinetobacter johnsonii (ATCC17909), with a homologous identity of 99%, and thus, strain ZY86 was identified as A. johnsonii. Analyses of the antifungal components showed that the active components produced by strain ZY86 were primarily amines, accounting for 20.80% of the total active components, which were followed, in order, by ketones, acids, esters, alcohols, peptides, hydrocarbons, alkanes, aldehydes, and alkenes in terms of proportion. In vitro testing showed that the control effect of strain ZY86 on strawberry gray mold was 84.14%, and higher the concentration, the better the control effect. In addition, strain ZY86 imparted a strong control effect against strawberry gray mold, and therefore, it is a promising biocontrol agent for agricultural production. (C) 2019 Friends Science Publishers
摘要：
The tobacco cutworm, Spodoptera litura, is an important pest of crop and vegetable plants worldwide, and its resistance to insecticides have quickly developed. However, the resistance mechanisms of this pest are still unclear. In this study, the change in mRNA and miRNA profiles in the susceptible, indoxacarb-resistant and field indoxacarb-resistant strains of S. litura were characterized. Nine hundred and ten co-up-regulated and 737 co-down-regulated genes were identified in the resistant strains. Further analysis showed that 126 co-differentially expressed genes (co-DEGs) (cytochrome P450, carboxy/cholinesterase, glutathione S-transferase, ATP-binding cassette transporter, UDP-glucuronosyl transferase, aminopeptidase N, sialin, serine protease and cuticle protein) may play important roles in indoxacarb resistance in S. litura. In addition, a total of 91 known and 52 novel miRNAs were identified, and 10 miRNAs were co-differentially expressed in the resistant strains of S. litura. Furthermore, 10 co-differentially expressed miRNAs (co-DEmiRNAs) had predicted co-DEGs according to the expected miRNA-mRNA negative regulation pattern and 37 indoxacarb resistance-related co-DEGs were predicted to be the target genes. These results not only broadened our understanding of molecular mechanisms of insecticide resistance by revealing complicated profiles, but also provide important clues for further study on the mechanisms of miRNAs involved in indoxacarb resistance in S. litura.
摘要：
Peptidoglycan recognition proteins (PGRPs) are important recognition receptors which play a critical role in signal identification and transmission in Toll or immune deficiency (IMD) pathways, particularly when pathogens evade and circumvent reactive oxygen species. Antimicrobial peptides (AMPs) synthesis can be activated by these signals to further eliminate pathogens. In this study, we cloned and characterized three different PGRP genes in Plutella xylostella strains, DBM1Ac-S, DBM1Ac-R and a field strain (DBMF). The results showed that PGRP1 belongs to the PGRP-SA family, PGRP2 to PGRP-LB, and PGRP3 to PGRP-LF. Moreover, PGRP1 expressed the highest transcript level, followed by PGRP3 and PGRP2, in two tissues including the gut and the larval carcass tissues of the DBM1Ac-S strain. Furthermore, altered expression levels of PGRP1-3 genes were detected in both gut and carcass tissues. Moreover, the DBM1Ac-R strain had the highest phenol oxidase (PO) activity among these three strains. The characterization of PGRP gene expression and PO activity in DBM1Ac-S, DBM1Ac-R and DBM-F provides insights into their important physiological roles in the immune system of P. xylostella exposed to Bt Cry1Ac toxin.
摘要：
Bacterial soft rot caused by Pectobacterium species is a serious disease in konjac (Amorphophallus konjac), a healthy source of starch particularly in East Asia. An effective diagnostic method is crucial to control the disease and reduce losses in konjac production. In this study, we evaluated a loop-mediated isothermal amplification (LAMP) assay with a specific primer set for the rapid and accurate detection of P. aroidearum. A comparative genomics approach was used to identify the specific genes suitable for the design of LAMP primers. The candidate target genes were determined through a first-round comparison with a 50-genome nucleotide database, and subjected to a second-round screening with the GenBank NR database. As a result, nine specific genes of P. aroidearum were selected for LAMP primer design. After screening of the primers, the primer set 1675-1 was chosen for LAMP detection owing to its high specificity and sensitivity. The LAMP assay could detect the presence of P. aroidearum genomic DNA at a concentration as low as 50 fg and 1.2 x 10(4) CFU/g artificially infected soil within 40 min at 65 degrees C. Subsequently, this primer set was successfully used to specifically detect P. aroidearum in naturally infected and non-symptomatic plant samples or soil samples from the field. This study indicates that a comparative genomic approach may facilitate the development of highly specific primers for LAMP assays, and a LAMP diagnostic assay with the specific primer set 1675-1 should contribute to the rapid and accurate detection of soft-rot disease in konjac at an early stage.
摘要：
The southern rice black-streaked dwarf virus (SRBSDV) causes significant economic damage to rice crops. This virus is transmitted to rice plants by the planthopper Sogatella furcifera (Horvath) in a persistent, circular, and propagative manner. Researchers currently lack suitable methods for assaying the activity of SRBSDV in vitro and preserving the virus all year. We used a microinjection method to directly inject SRBSDV extracts into the hemocoel of S. furcifera nymphs. SRBSDV was subsequently detected by Reverse Transcription-Polymerase Chain Reaction in more than 56.7% of the insects after 5 d and 60% of healthy rice plants fed by these insects also became SRBSDV infected. Moreover, injecting planthopper with an extract of SRBSDV-infected rice plant that had been frozen at -80 degrees C for 220 d caused 63.3% to become viruliferous. These results indicate that SRBSDV can be successfully transmitted to S. furcifera by microinjection, and that extracts of SRBSDV-infected rice plants frozen at -80 degrees C for 220 d still contain sufficient active SRBSDV to infect S. furcifera. We provide a novel way to preserve SRBSDV all year by injecting S. furcifera with the SRBSDV extract.
摘要：
Bradysia odoriphaga Yang et Zhang is a serious below ground pest of Chinese chives (Allium tuberosum). Our previous studies have indicated that B. odoriphaga females prefer to oviposit near the roots of Chinese chives rather than the roots of other plants, and that the performance (longevity and fecundity) of B. odoriphaga offspring was better on Chinese chives than on Lettuce (var. ramosa Hort.), Onion (Allium cepa) and Potato (Solanum tuberosum) but little is known about how the volatiles released by Chinese chives affect the host-finding and oviposition behaviors of B. odoriphaga. Here, we used gas chromatography-mass spectrometry and determined that Chinese chives releases the following volatiles: methyl allyl disulfide, beta-myrcene, cis-ocimene, diallyl disulfide, nonane, n-dodecane, n-tetradecane, and n-hexadecane; quantities released were highest for methyl allyl disulfide and diallyl disulfide. In addition to eliciting strong responses in females in electroantennography assays, the latter two sulfur compounds and their mixtures attracted females in Y-tube olfactometer assays. The addition of methyl allyl disulfide, diallyl disulfide, or a mixture of the two compounds at a 1:5 ratio to chive plants increased oviposition when compared to control plants. These results indicate that methyl allyl disulfide and diallyl disulfide, either alone or in combination, influence the host-seeking behavior of B. odoriphaga.
摘要：
A novel phenazine-l-carboxamide-derived 18-1 (PCND 18-1) was evaluated in terms of its potential for the development and enrichment of new biofungicides for the control of rice sheath blight caused by Rhizoctonia solani. PCND 18-1 exhibited fungicidal activity against R. solani, showing an inhibition rate of 87.64%, with a 50% effective concentration (EC50) 4.25 mu g/mL, regression equation of Y = 0.7105x + 3.8428; and correlation coefficient of 0.9817, which are indicative of its potential as a natural biofungicide. PCND 18-1 also attenuated the pathogenicity of R. solani, which was concentration-dependent. Additionally, the action mode of PCND 18-1 against rice sheath blight (R. solani) was protective better than curative activity under greenhouse condition, as reflected by the corresponding EC50 values of 2.49 and 5.72 mu g/mL. PCND 18-1 can translocate in rice with a low translocation capacity and exhibited a higher capacity for upward (root-leaf) translocation than for downward (leaf-root) translocation. Furthermore, PCND 18-1 demonstrated adhesion to leaves but poor tolerance against rain-washing. The optimal persistence period of PCND 18-1 on rice was 7 d. (C) 2018 Friends Science Publishers
