Evaluation of Lethal Effects of Chlorantraniliprole on Chilo suppressalis and Its Larval Parasitoid, Cotesia chilonis

Chlorantraniliprole was introduced into China from 2008 as a novel insecticide to control the rice stem borer, Chilo suppressalis （Walker）. Cotesia chilonis （Matsumura） is the major parasitoid of C. suppressalis. We collected seven populations of C. suppressalis and two populations of C. chilonis in different locations in China in 2009 to investigate the lethal effects of chlorantraniliprole on them. The populations of C. suppressalis from different regions showed various LD50 values ranging from 2.00 to 18.70 ng per larva. Chlorantraniliprole has negligible acute contact toxicity （LC50500 mg L-1） to C. chilonis and its oral toxicity is also much lower than that of fipronil （2 800-fold difference in LC50）. The results indicated that chlorantraniliprole is a good alterative in rice integrated pest management （IPM） programs. The susceptibility data of C. suppressalis will be useful for monitoring resistance levels in future.

Synthesis and Crystal Structure of 2-Oxo-3-phenyl-1-oxaspiro[4.5]dec-3-en-4-yl 4-chlorobenzoate

The title compound 2-oxo-3-phenyl-1-oxaspiro[4.5]dec-3-en-4-yl 4-chlorobenzoate 6 （C22H19ClO4, Mr = 382.82） has been synthesized by the condensation reaction of 4-hydroxy-3-phenyl-1-oxaspiro[4.5]dec-3-en-2-one 5 with 4-chlorobenzoyl chloride, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 10.6749（11）, b = 6.0573（7）, c = 29.680（2） A, β = 94.073（3）°, V= 1914.3（3） A^3, Z = 4, Dc = 1.328 g/cm^3, F（000） = 800, μ = 0.224 mm^-1, S = 1.003, the final R = 0.0605 and wR = 0.1500 for 1828 observed reflections with I〉 2σ（I） and 244 variable parameters. The crystal analysis shows that the molecular structure of the title compound has one planar furan ring, one chair conformation cyclohexane ring and two benzene rings. The furan and cyclohexane rings adopt whorl conformations.

Synthesis and antifungal activity of trichodermin derivatives

一系列衍生物从是 Trichoderma 出租车 sp 生产的抗真菌的代谢物的 trichodermin (1 ) 被综合。nov。他们的结构被 1H NMR 证实， MS 光谱。他们的抗真菌的活动在 vitro 被评估。初步的结构活动关系(SAR ) 结果显示双契约， epoxide 一半和酉旨组是主要 pharmacophore 元素， C4 位置的立体化学也起了一个关键作用，并且混合物 1e 鈥 ? g 显示了对比 1 的 Magnaporthe grisea 的更强壮的抗真菌的活动。

Crossing experiments and behavioral observations reveal reproductive incompatibility among three putative species of the whitefly Bemisia tabaci

The whitefly Bemisia tabaci has a global distribution and extensive genetic diversity. Recent phylogenetic analyses as well as crossing experiments suggest that B. tabaci is a complex composed of 〉 20 cryptic species, but more crossing studies are required to examine the reproductive compatibility among the putative species and thus further clarify the systematics of this species complex. We conducted crossing experiments and behavioral observations to investigate the reproductive compatibility between the Mediterranean, Asia II 3, and Asia II 1 putative species ofB. tabaci collected from Zhejiang, China. Female progeny were never produced in inter-species crosses, demonstrating a lack of egg fertilization; while 55%-75% females were produced in all the intra-species treatments. Continuous behavioral observations showed that frequent courtship events occurred in both intra-species treatments and inter-putative species crosses. However, copulation events occurred only in the three intra-species treatments with one exception： that one copulation event occurred between Asia II 3 and Mediterranean in the crosses where two cohorts of females and males of different putative species were enclosed together in a small arena but were not allowed access to their intra-specific mates for a long period of time. These data demonstrated complete reproductive isolation between the Mediterranean, Asia II 3, and Asia II 1 putative species, and further showed that the isolation is due to lack of copulation. Demonstration of reproductive isolation between the Mediterranean and two indigenous putative species from China provides further evidence for the existence of cryptic species within the B. tabaci complex.

Gene expression profiling of the whitefly （Bemisia tabaci） Middle East- Asia Minor 1 feeding on healthy and Tomato yellow leaf curl China virus-infected tobacco

Begomoviruses are exclusively transmitted by whitefly （Bemisia tabaci） in a circulative, non-propagative manner. The influences of begomoviruses on whitefly vector are complex with both direct and indirect effects. However, the molecular mechanisms underlying these effects are poorly understood and the transcriptional profiles of whitefly on healthy and virus-infected plants have not yet been studied. Using suppression subtractive hybridization, we investigated the differentially expressed genes in whitefly Middle East - Asia Minor 1 feeding on healthy and Tomato yellow leaf curl China virus （TYLCCNV） infected tobacco. From the forward cDNA library, 124 differentially expressed expression sequence tags （ESTs） were obtained which represent up-regulated genes in the whiteflies feeding on the infected tobacco. From the reverse library, 112 ESTs were isolated which represent down-regulated genes. Among the up-regulated genes, we identified several genes that are probably involved in direct interaction between whitefly and TYLCCN~, including a 26/29-kDa proteinase that appears to participate in the elimination of foreign proteins, heparan sulfate proteoglycan which mediates the entry of several viruses into host cells and two genes of Rickettsia-a secondary endosymbiotic bacterium of whitefly. In addition, we identified a number of genes involved in metabolism, transcription and translation which might be the result of indirect effects of TYLCCNV on the whitefly via host plants. Collectively, our results suggest that TYLCCNV-infected tobacco changes the gene expression profiles of whitefly via both direct and indirect interactions. This study revealed a number of genes involved in whitefly-TYLCCNV-tobacco interactions and provided useful information for future study on this complex system.

Tomato yellow leaf curl virus infection of tomato does not affect the performance of the Q and ZHJ2 biotypes of the viral vector Bemisia tabaci

To better understand the etiology of begomovirus epidemics in regions under invasion we need to know how indigenous and invasive whitefly vectors respond to virus infection. We investigated both direct and indirect effects of infection with Tomato yellow leaf curl virus （TYLCV） on the performance of the invasive Q biotype and the indigenous Asian ZHJ2 biotype of whitefly Bemisia tabaci. The Q biotype performed better than the ZHJ2 biotype on either uninfected or virus-infected tomato plants. However, virus-infection of host plants did not, or only marginally affected, the performance of either biotype of whiteflies in terms of fecundity, longevity, survival, development and population increase. Likewise, association of the vectors with TYLCV did not affect fecundity and longevity of the Q or ZHJ2 biotypes on cotton, a non-host of TYLCV. These results indicate that the alien Q biotype whitefly, but not the indigenous ZHJ2 biotype, is likely to become the major vector of TYLCV in the field and facilitate virus epidemics.

Biological and biochemical characterization of a red-eye mutant in Nilaparvata lugens （Hemiptera： Delphacidae）

A red-eye colony was established in our laboratory in brown planthopper （BPH）, Nilaparvata lugens （Stal）, a major rice pest in Asia. Except for the red-eye phenotype, no other differences were observed between the wild-type （brown eye） and the mutant-type （red eye） in external characters. Genetic analysis revealed that the red-eye phenotype was controlled by a single autosomal recessive allele. Biological studies found that egg produc- tion and egg viability in the red-eye mutant colony were not significantly different from those in the wild-type BPH. Biochemical analysis and electronic microscopy examination revealed that the red-eye mutants contained decreased levels of both xanthommatin （brown） and pteridine （red） and reduced number of pigment granules. Thus, the changes of amount and ratio of the two pigments is the biochemical basis of this red-eye mutation. Our results indicate that the red-eye mutant gene （red） might be involved in one common gene locus shared by the two pigments in pigment transportation, pigment granule formation or some other processes.

Molecular characterization of a proline transporter from Chilo suppressalis

Proline plays an important role in regulating synaptic neurotransmission in both mammalian and insect nervous systems. The full-length complementary DNA sequences encoding the proline transporter gene （CsProT） and its alternative spliced transcript （CsProT-ST） were cloned from the striped stem borer （SSB）, Chilo suppressalis, one of the most important rice pests in Asia. The comparison of amino acid sequences showed that CsProT is highly similar to the proline transporter isolated from Manduca sexta （MasProT）. The developmental changes of the relative messenger RNA expression levels of CsProT and CsProT-ST genes were examined in SSB. The expression level of CsProT-ST is much higher than that of CsProT in all developmental periods, suggesting that the Y-end spliced variant is the major transcript instead of CsProT. The highest ex- pression level of both genes in the pupal stage means that proline may be involved in some unclear functions in the metamorphosis from pupa to adulthood.

Viral infection of tobacco plants improves performance of Bemisia tabaci but more so for an invasive than for an indigenous biotype of the whitefly

The ecological effects of plant-virus-vector interactions on invasion of alien plant viral vectors have been rarely investigated. We examined the transmission of Tomato yellow leaf curl China virus (TYLCCNV) by the invasive Q biotype and the indigenous ZHJ2 biotype of the whitefly Bemisia tabaci, a plant viral vector, as well as the influence of TYLCCNV-infection of plants on the performance of the two whitefly biotypes. Both whitefly biotypes were able to acquire viruses from infected plants and retained them in their bodies, but were unable to transmit them to either tobacco or tomato plants. However, when the Q biotype fed on tobacco plants infected with TYLCCNV, its fecundity and longevity were increased by 7- and 1-fold, respectively, compared to those of the Q biotype fed on uninfected tobacco plants. When the ZHJ2 biotype fed on virus-infected plants, its fecundity and longevity were increased by only 2- and 0.5-fold, respectively. These data show that the Q biotype acquired higher beneficial effects from TYLCCNV-infection of tobacco plants than the ZHJ2 biotype. Thus, the Q biotype whitefly may have advantages in its invasion and displacement of the indigenous ZHJ2 biotype.

The presence of six cryptic species of the whitefly Bemisia tabaci complex in China as revealed by crossing experiments

Recent phylogenetic analysis using mitochondrial cytochrome oxidase I （mtCOI） sequences ofBemisia tabaci worldwide indicates that the whitefly comprises at least 24 morphologically indistinguishable but genetically distinct cryptic species. While evidence of reproductive isolation has been reported for some of the putative species, more extensive crossing experiments are required to clarify the systematics of this species com- plex. In this study, we established laboratory cultures for six putative species ofB. tabaci collected in China. We conducted 22 inter-species crosses among the six putative species. The data and those reported previously were collated, and the combined dataset covered all the 30 possible inter-species crosses among the six putative species. Intra-species controls always produced female and male progeny and the proportions of females in the first gen- eration （F1） ranged from 56% to 70%. However, in inter-species crosses female progeny were rarely produced, and the few F1 females produced in four of the 30 inter-species crosses were either sterile or significantly weaker in viability. These results demonstrate a pattern of complete reproductive isolation among the six putative species and show that they are six cryptic species in the B. tabaci complex.

Differential efficiency of a begomovirus to cross the midgut of different species of whiteflies results in variation of virus transmission by the vectors

Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the mechanisms governing differential transmission of begomoviruses by different species of the Bemisia tabaci complex remain largely unknown. Here we firstly compared the transmission efficiency of tobacco curly shoot virus(TbCSV) by four species of the B. tabaci complex and found that Asia II 1 transmitted this virus with the highest efficiency, whereas MEAM1 transmitted it with the lowest. Next, by performing quantitative analysis of virus and immune-fluorescence detection, we found that the efficiency of TbCSV to cross the midgut wall was higher in Asia II 1 than in MEAM1. Finally, we set the quantities of virions in the haemolymph to the same level in Asia II 1 and MEAM1 via injection and then compared their capacity in TbCSV transmission, and found that the difference in TbCSV transmission between them became smaller. Taken together, our findings suggest that the efficiency of a begomovirus to cross the midgut wall of a whitefly to reach the vector's haemolymph plays a significant role in determining transmission of the virus.

Overhauling the assessment of agrochemical-driven interferences with microbial communities for improved global ecosystem integrity

Recent studies have shown that various agrochemicals can substantially affect microbial communities;especially those that are associated with cultivated plants.Under certain circumstances,up to 50% of the naturally occurring microorganisms can be negatively affected by common agricultural practices such as seed coating with fungicide-based matrices.Nevertheless,the off-target effects of commonly applied agrochemicals are still understudied in terms of their interferences with microbial communities.At the same time,agrochemical inputs are steadily increasing due to the intensification of agriculture and the increasing pathogen pressure that is currently observed worldwide.In this article,we briefly reflect on the current knowledge related to pesticide interference with microbial communities and discuss negative implications for the plant holobiont as well as such that are spanning beyond local system borders.Cumulative effects of pesticide inputs that cause alterations in microbial functioning likely have unforeseen implications on geochemical cycles that should be addressed with a high priority in ongoing research.A holistic assessment of such implications will allow us to objectively select the most suitable means for food production under the scenario of a growing global population and aggravating climatic conditions.We present three hypothetical solutions that might facilitate a more sustainable and less damaging application of pesticides in the future.

Termites and Chinese agricultural system: applications and advances in integrated termite management and chemical control

Termites are eusocial arthropod decomposers,and improve soil fertility,crop yield,and also are used by humans for their ben efits across the world.However,some species of termites are becoming a threat to the farming community as they are directly and indirectly causing major losses to the agricultural system.It is estimated that termites cost the global economy more than 40 billion USD annually,and considerable research has been done on their management.In this review,we present the available information related to sustainable and integrated termite management practices(ITM).Furthermore,we insist that the better management of this menace can be possible through:(i)improving traditional methods to keep termites away from crops;(ii)improving agricultural practices to maintain plants with more vigor and less susceptible to termite attack;and(iii)integration of available techniques to reduce termite infestation in crops and surroundings.The application of an effective combination of traditional practices with recently developed approaches is the best option for agricultural growers.Moreover,keeping in mind the beneficial nature of this pest,more innovative efforts for its management,particularly using rapidly emerging technology(e.g.,RNA interference),are needed.

Transcriptional memory and response to adverse temperatures in plants

Temperature is one of the major environmental signals controlling plant development,geographical distribution,and seasonal behavior.Plants perceive adverse temperatures,such as high,low,and freezing temperatures,as stressful signals that can cause physiological defects and even death.As sessile organisms,plants have evolved sophisticated mechanisms to adapt to recurring stressful environments through changing gene expression or transcriptional reprogramming.Transcriptional memory refers to the ability of primed plants to remember previously experienced stress and acquire enhanced tolerance to similar or different stresses.Epigenetic modifications mediate transcriptional memory and play a key role in adapting to adverse temperatures.Understanding the mechanisms of the formation,maintenance,and resetting of stress-induced transcriptional memory will not only enable us to understand why there is a trade-off between plant defense and growth,but also provide a theoretical basis for generating stress-tolerant crops optimized for future climate change.In this review,we summarize recent advances in dissecting the mechanisms of plant transcriptional memory in response to adverse temperatures,based mainly on studies of the model plant Arabidopsis thaliana.We also discuss remaining questions that are important for further understanding the mechanisms of transcriptional memory during the adverse temperature response.

The receptor-like cytosolic kinase RIPK activates NADP-malic enzyme 2 to generate NADPH for fueling ROS production

Reactive oxygen species(ROS)production is a conserved immune response in Arabidopsis primarily medi-ated by respiratory burst oxidase homolog D(RBOHD),a nicotinamide adenine dinucleotide phosphate(NADPH)oxidase associated with the plasma membrane.A rapid increase in NADPH is necessary to fuel RBOHD proteins and thus maintain ROS production.However,the molecular mechanism by which NADPH is generated to fuel RBOHD remains unclear.In this study,we isolated a new mutant allele of FLAGELLIN-INSENSITIVE 4(FIN4),which encodes the first enzyme in de novo NAD biosynthesis.fin4 mu-tants show reduced NADPH levels and impaired ROS production.However,FIN4 and other genes involved in NAD-and NADPH-generating pathways are not highly upregulated upon elicitor treatment,raising a pos-sibility that a cytosolic NADP-linked dehydrogenase might be post-transcriptionally activated to maintain the NADPH supply close to RBOHD.To verify this possibility,we isolated the proteins associated with RPM1-INDUCED PROTEIN KINASE(RIPK),a receptor-like cytoplasmic kinase that regulates broad-spectrum ROS signaling in plant immunity,and identified NADP-malic enzyme 2(NADP-ME2),an NADPH-generating enzyme.Compared with wild-type plants,nadp-me2 mutants display decreased NADP-ME activity,lower NADPH levels,and reduced ROS production in response to immune elicitors.Furthermore,we found that RIPK can directly phosphorylate NADP-ME2 and enhance its activity in vitro.The phosphorylation of the NADP-ME2 S371 residue contributes to ROS production upon immune elicitor treatment and susceptibility to the necrotrophic bacterium Pectobacterium carotovorum.Collectively,our study suggests that RIPK phosphorylates and activates NADP-ME2 to rapidly increase cytosolic NADPH,thus fueling RBOHD to sustain ROS production in plant immunity.

Gut microbiota dysbiosis involves in host non-alcoholic fatty liver disease upon pyrethroid pesticide exposure

A growing body of evidence has demonstrated the significance of the gut microbiota in host health,while the association between gut microbiota dysbiosis and multiple diseases is yet elusive in the scenario of exposure to widely used pesticides.Here,we show that gut microbiota dysbiosis involves in host's abnormal lipid metabolism and consequently the non-alcoholic fatty liver disease in Xenopus laevis upon exposure to cis-bifenthrin,one of the most prevalent pyrethroid insecticides in the world.With the guidance of gut microbiota analysis,we found that cis-bifenthrin exposure significantly perturbed the gut microbial community,and the specific taxa that served as biomarkers were identified.Metabolomics profiling and association analysis further showed that a significant change of intestinal metabolites involved in lipid metabolic pathways were induced along with the microbiota dysbiosis upon exposure to cis-bifenthrin.Detailed investigation showed an altered functional regulation of lipids in the liver after cis-bifenthrin exposure and the accumulation of lipid droplets in hepatocytes.Specifically,a change in deoxycholic acid alters bile acid hepatoenteral circulation,which affects lipid metabolism in the liver and ultimately causes the development of fatty liver disease.Collectively,these findings provide novel insight into the gut microbiota dysbiosis upon pesticide exposure and their potential implication in the development of chronic host diseases related to liver metabolic syndrome.