The tomato yellow leaf curl virus (TYLCV), spread by the vector insect Bemisia tabaci, dramatically reduces worldwide tomato production and quality. Plant-mediated interactions between TYLCV and vector whiteflies commonly occur when previous infestations induce both volatile and nonvolatile changes in the shared host. These induced changes of the shared host may differentially affect subsequent interacting species within the plant-insect-virus tripartite system. These altered volatile profiles can be perceived as airborne cues that enhance or suppress defense responses in neighboring conspecifics, a phenomenon known as "plant-plant communication." Here, we present the first evidence that TYLCV-infected Mediterranean (MED) B. tabaci (hereafter referred to as viruliferous MED) preferentially settles and oviposits on previously infested peppers, an alternative host for TYLCV, over those merely exposed and intact ones. Furthermore, differences in feeding behavior of viruliferous MED, assessed using an electrical penetration graph, clearly indicate that these MED whiteflies feed more effectively on previously infested and exposed peppers than on healthy ones. Our results suggest that the suppression of pepper defenses-both nonvolatile and volatile-by previous infestation and exposure to viruliferous MED promotes alternative host-mediated mutualism between MED and TYLCV. These findings provide insight into peppers, functioning as alternative hosts, mediating the interactions between TYLCV and its vector MED whiteflies. Moreover, our results may enhance the understanding of TYLCV epidemics, particularly in the context of the rapid invasion of MED B. tabaci, thereby facilitating the development of novel management strategies for controlling this viral pathogen and its devastating whiteflies.

Nitrogen is an essential element for all life on earth. Nitrogen metabolism, including excretion, is essential for growth, development, and survival of plants and animals alike. Several nitrogen metabolic processes have been described, but the underlying molecular mechanisms are unclear. Here, we reveal a unique process of nitrogen metabolism in the whitefly Bemisia tabaci , a global pest. We show that it has acquired two bacterial uricolytic enzyme genes, B. tabaci urea carboxylase ( BtUCA ) and B. tabaci allophanate hydrolase ( BtAtzF ), through horizontal gene transfer. These genes operate in conjunction to not only coordinate an efficient way of metabolizing nitrogenous waste but also control B. tabaci ’s exceptionally flexible nitrogen recycling capacity. Its efficient nitrogen processing explains how this important pest can feed on a vast spectrum of plants. This finding provides insight into how the hijacking of microbial genes has allowed whiteflies to develop a highly economic and stable nitrogen metabolism network and offers clues for pest management strategies.

为明确天津市烟粉虱Bemisia tabaci隐种的类别及其寄主适应性、传毒能力、携带内共生菌情况和抗药性,采用mtCOI酶切法对从武清、西青、蓟州和宁河4个区的番茄、黄瓜及辣椒3种寄主上采集的12个烟粉虱种群进行隐种鉴定,采用PCR检测其携带番茄黄化曲叶病毒(tomato yellow leaf curl virus,TYLCV)和内共生菌情况,并采用浸叶法测定其对4种常用药剂的抗性.结果表明,采集的烟粉虱种群以MED隐种为主,占所有检测个体的93.33％,有3个种群为MED和MEAM1隐种混合发生.所有检测个体中有36.25％的个体携带TYLCV,在6个种群中检测到TYLCV,其中5个种群有超过50％的个体携带TYLCV.在12个种群中共检测到Hamiltonella、立克次氏体Rickett-sia、Cardinium和杀雄菌属Arsenophnus共4种内共生菌,携带个体比例分别为90.63％、48.96％、43.75％和8.33％,进一步对内共生菌协同感染情况进行分析,发现有HARC、HRC、HAC、HR、HC和AC共6个协同感染型,感染率分别为4.17％、28.13％、3.13％、14.58％、5.21％和1.04％.阿维菌素对天津市烟粉虱种群的毒力普遍较高,LC50介于0.05～0.66 mg/L之间,噻虫嗪的毒力则普遍较低,LC50介于267.63～2 998.80 mg/L之间.4种药剂对其中9个种群的毒力顺序为阿维菌素＞溴氰虫酰胺＞吡虫啉＞噻虫嗪,对另外3个种群的毒力顺序为阿维菌素＞吡虫啉＞溴氰虫酰胺＞噻虫嗪.

挖掘本土天敌资源是害虫生物防治的有效手段.桨角蚜小蜂Eretmocerus spp.是烟粉虱Bemisia tabaci重要的寄生性天敌之一,明确桨角蚜小蜂本地种类及遗传分化关系,对本土天敌资源挖掘具有重要意义.本研究在天津5个地区采集了 13个地理、寄主的桨角蚜小蜂种群,利用线粒体mtDNA COⅠ基因片段作为分子标记,进一步通过MEGAX、DnaSP 5.10等软件进行遗传分化分析.结果表明,本研究所采种群中包含2种桨角蚜小蜂,其中测得蒙氏桨角蚜小蜂Eretmocerus mundus mtDNA COⅠ基因序列20条(755 bq),未命名桨角蚜小蜂Eretmocerus sp.WTT-2016 mtDNA COⅠ基因序列20条(739 bq).两种桨角蚜小蜂的遗传多样性均较低,其中蒙氏桨角蚜小蜂Hd=0.368,Pi=0.00557,K=4.205;未命名桨角蚜小蜂 Hd=0.616,Pi=0.00106,K=0.784.错配分析表明,蒙氏桨角蚜小蜂在天津种群较稳定,近年来未出现扩张现象.

近年来,天津地区蔬菜作物蓟马发生危害愈发严重.为防止其种群扩大,减少经济损失,采集了天津地区11个蓟马种群,对其mtCOⅠ基因进行测序,共获得29条蓟马mtCOⅠ基因序列,其中发现37个变异位点,5种单倍型,H1单倍型出现次数最多.经Genbank序列比对,发现该11个蓟马种群全部为棕榈蓟马(Thrips palmi Karny).进一步利用MEGA 10.0.0和Dna SP 5.10软件对所得序列进行遗传分化、基因流、系统发育分析,发现所测棕榈蓟马总群体的遗传多样性较低,种群间遗传分化程度中等,种群间基因流较高,但是种群间遗传分化较小,错配分析曲线出现多峰,且天津地区棕榈蓟马种群在最近的历史时期种群相对较为稳定,没有出现较为明显的种群扩张现象.研究结果为当地棕榈蓟马制定科学合理的防治策略提供依据.

Two cryptic species of the Bemisia tabaci species complex, MEAM1 (Middle East-Asia Minor 1) and MED (Mediterranean), are highly destructive herbivores. Attack by herbivorous insects often induces defense responses in plants, including the accumulation of toxic secondary metabolites, the synthesis of herbivore-induced plant volatiles (HIPVs) and defensive proteins, and the release of volatile organic compounds that attract natural enemies. These defense responses, which often differ depending on the herbivore, may affect the preference and performance of later-arriving con- and heterospecific whiteflies that attack the same plant. In the present study, we found that MEAM1 whiteflies preferred settling and ovipositing on non-infested and MED-infested cabbage over MEAM1-infested cabbage plants, but that MED whiteflies showed no significant difference in settling or oviposition preference among non-infested, MEAM1-infested, and MED-infested plants. MEAM1 infestation increased the contents of total phenols and flavonoids in cabbage, which coincided with the increased expression of the following genes in the phenylpropanoid biosynthesis pathway: PAL2 , C4H , and 4CL . Soluble protein contents were also markedly higher in the MEAM1-infested cabbage plants than in the non-infested and MED-infested cabbage plants. Overall, these results demonstrate that previous infestation by MEAM1 and MED whiteflies induced defense responses in cabbage plants that had different effects on the host preference and performance of later-arriving con- and heterospecific whiteflies. Phenolic compounds may be the key factors influencing host choice by MEAM1 and MED whiteflies on cabbage plants.

Pesticides primarily affect target organisms via direct toxicity, but may also alter the feeding behaviors of surviving individuals in ways that alter their effect on host plants. The latter impact is especially important when pests can transmit plant pathogens. The Mediterranean (MED) population of the sweetpotato whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) transmits Tomato yellow leaf curl virus (TYLCV), a pathogen that can be economically devastating in field and greenhouse cropping systems. We first assessed the impact of sublethal (LC15) and label concentrations of flupyradifurone, a butenolide-derived insecticide, on the feeding behavior of TYLCV-infected MED on tomato. We next measured the effect of flupyradifurone on plant TYLCV load, vector transmission efficiency, and MED survival. Both the LC15 and label flupyradifurone concentrations dramatically altered MED feeding and caused the near cessation of both salivation and phloem ingestion (necessary for viral transmission and acquisition, respectively). Both concentrations also significantly reduced plant TYLCV load, and the label rate of flupyradifurone sharply decreased TYLCV transmission while killing >99% of MED. As the first report of pesticide-induced changes in the feeding behavior of viruliferous Bemisia, our findings highlight the potential importance of chemically driven feeding cessation in the control of TYLCV and other Bemisia-transmitted plant pathogens.

Many damaging agricultural pests can, in addition to their direct feeding damage, acquire and transmit plant pathogens. Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is considered a 'supervector' of disease-causing plant pathogens and viruses. One of the most damaging of these is Tomato yellow leaf curl virus (TYLCV), a circulatively transmitted begomovirus than can extensively damage field and greenhouse crops. Because sustained feeding periods are necessary to acquire and transmit circulatively transmitted viruses, pesticides that, in addition to their direct lethality, suppress feeding in surviving individuals may be particularly effective in decreasing viral transmission. We assessed the impact of sulfoxaflor, a sulfoximine insecticide, on the settling preference, feeding, and viral transmission of TYLCV-carrying B. tabaci on tomato. We found that viruliferous B. tabaci avoided both settling and feeding on sulfoxaflor-treated plants, and that sulfoxaflor virtually eliminated the transmission of TYLCV by B. tabaci. The antifeedant properties of sulfoxaflor have previously been reported in other pest systems; our results document similar effects on viruliferous B. tabaci and demonstrate that this pesticide can reduce TYLCV transmission by surviving individuals.

BACKGROUND Over recent decades, many efficacious insecticides have been applied for control of Bemisia tabaci, one of the most notorious insect pests worldwide. Field-evolved insecticide resistance in B. tabaci has developed globally, but remains poorly understood in China. RESULTS In this study, a total of 30 field samples of the whitefly Bemisia tabaci from eight provinces of China were collected in 2015 to 2018. Twenty-four of the populations were identified as Mediterranean, 'Q' type (MED), three were Middle East-Asia Minor 1, 'B' type (MEAM1), and three were mixtures of MED/ MEAM1. After identifying whether they belong to MED or MEAM1, the selected individuals were used in bioassays assessing insecticide resistance to abamectin, thiamethoxam, spirotetramat, cyantraniliprole, and pyriproxyfen. Our results showed that all populations in the eight regions had little or no resistance to abamectin; abamectin resistance was highest in the Hunan (Changsha) and Hubei (Wuhan) regions and was lowest in the island region of Hainan (Sanya). The resistance of B. tabaci to spirotetramat, cyantraniliprole, and pyriproxyfen increased each year. The resistance to thiamethoxam remained low because of the high LC50 value for the laboratory strain. CONCLUSION These findings suggest that a rotation system using efficacious B. tabaci insecticides with differing mode of actions ought to be implemented for sustainable control to reduce the potential of resistance development. This study provides important data to support the integrated pest management and insecticide resistance management of B. tabaci in China.

Two cryptic species of the Bemisia tabaci species complex, MEAM1 (Middle East-Asia Minor 1) and MED (Mediterranean), are highly destructive herbivores. Attack by herbivorous insects often induces defense responses in plants, including the accumulation of toxic secondary metabolites, the synthesis of herbivore-induced plant volatiles (HIPVs) and defensive proteins, and the release of volatile organic compounds that attract natural enemies. These defense responses, which often differ depending on the herbivore, may affect the preference and performance of later-arriving con- and heterospecific whiteflies that attack the same plant. In the present study, we found that MEAM1 whiteflies preferred settling and ovipositing on non-infested and MED-infested cabbage over MEAM1-infested cabbage plants, but that MED whiteflies showed no significant difference in settling or oviposition preference among non-infested, MEAM1-infested, and MED-infested plants. MEAM1 infestation increased the contents of total phenols and flavonoids in cabbage, which coincided with the increased expression of the following genes in the phenylpropanoid biosynthesis pathway: PAL2, C4H, and 4CL1. Soluble protein contents were also markedly higher in the MEAM1-infested cabbage plants than in the non-infested and MED-infested cabbage plants. Overall, these results demonstrate that previous infestation by MEAM1 and MED whiteflies induced defense responses in cabbage plants that had different effects on the host preference and performance of later-arriving con- and heterospecific whiteflies. Phenolic compounds may be the key factors influencing host choice by MEAM1 and MED whiteflies on cabbage plants.

取食是烟粉虱Bemisia tabaci(Gennadius)传播植物病毒最重要的途径之一.本研究利用昆虫刺探电位(EPG)技术研究了杀虫剂溴氰虫酰胺亚致死浓度(LC15)对携带番茄黄化曲叶病毒(TYLCV)MED烟粉虱取食行为和传毒效率的影响.结果表明,溴氰虫酰胺对未携毒和携毒MED烟粉虱的亚致死浓度(LC15)分别为1.52 mg/kg和1.75 mg/kg,差异不显著.携毒烟粉虱在溴氰虫酰胺亚致死浓度处理的番茄苗上取食,第一次刺探起始时间显著推迟,是对照番茄苗上的3.7倍.在韧皮部取食阶段,处理组烟粉虱在韧皮部分泌唾液平均时间、吸食汁液总时间和平均时间均显著缩短,分别是对照组的0.10倍、0.14倍和0.10倍,韧皮部取食能力显著降低.qPCR试验研究表明,溴氰虫酰胺亚致死浓度处理极显著的降低了烟粉虱的传毒效率,携毒烟粉虱取食48 h的番茄苗培养10 d后,TYLCV相对含量仍接近于0,表明溴氰虫酰胺对烟粉虱传播TYLCV具有良好的控制潜力.研究结果为科学合理的使用化学农药防治烟粉虱及其传播的双生病毒病提供理论依据.

Facultative endosymbionts can affect the growth, physiology, and behavior of their arthropod hosts.There are several endosymbionts in the invasive whitefly Bemisia tabaci Mediterranean (MED, Q biotype) that influence host fitness by altering stylet probing behavior. We investigated the probing behavior of B. tabaci MED infected with the facultative endosymbiont Candidatus Cardinium hertigii (Cardinium (Sphingobacteriales: Flexibacteraceae)). We generated genetically similar Cardinium-infected (C*(+)) and uninfected (C-) clonal sublines and analyzed the probing behavior of newly emerged adult on cotton (Malvales: Malvaceae), Gossypium hirsutum L., using electropenetrography (EPG). The C- subline demonstrated a longer duration of E2 (2.81-fold) and more events of E2 (2.22-fold) than the C*(+) subline, indicating a greater level of sustained ingestion of plant phloem.These findings provide insight into the fitness costs (fitness of a particular genotype is lower than the average fitness of the population) of the Cardinium-infected B. tabaci.

Background: Graphene quantum dots (GQDs) have great potential for bioimaging, biosensor, drug carrier, theranostics, and are recently reported as therapeutic agents to treat amylosis and inflammation. Most types of GQDs have proven low toxicity in previous studies, but data about the transcriptomic responses of in vivo systems exposed to various GQDs remains largely unknown. Results: We examined the mRNA and microRNA (miRNA) expression changes of zebrafish embryos exposed to four types of GQDs at a safe concentration (100 µg/mL), respectively as raw graphene quantum dots (R-GQDs), graphene oxide quantum dots (GOQDs), carboxyl GQDs (C-GQDs), and aminated GQDs (A-GQDs). The four GQDs elicited the number of differentially expressed genes (DEGs) in a decreasing order of A-GQDs, GOQDs, C-GQDs and R-GQDs to act on protein folding, potassium (K + ) and calcium (Ca 2+ ) channels, and spliceosome to varying degrees. Among the four GQDs, A-GQDs caused more genotoxic effects associated with lipid and hormone metabolism, MAPK signaling pathway, complement system, and ferropotosis. miRNA-seq data revealed that GOQDs aroused more differentially expressed miRNAs (DEMs), far exceed the total number of DEMs induced by the other three GQDs. dre-miR-735-5p and its potentially interactive gene-myogenin ( myog ) were identified as the only negatively-correlated miRNA-target gene pair shared by the four GQDs treatments. Conclusion: Taken together, this study provided substantial data underlying the common and specific transcriptomic responses of in vivo systems exposed to various types of GQDs, and also indicated the potential medicinal values of GQDs for ion antagonists and spliceosome-targeted therapies.

Worldwide, the most two important cryptic species of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) are MEAM1 (Middle East–Asia Minor 1, “B” biotype) and MED (Mediterranean, “Q” biotype). Although both B. tabaci MEAM1 and MED are polyphagous, they differ greatly in host choice and performance on various host plants. MEAM1 prefer to settle and perform better than MED on cabbage (Brassica oleracea), for example, but the underlying mechanism is largely unexplored. In the present study, we first measured the contents of the main secondary insect‐resistant substances (glucosinolates and phenolics) and main nutrients (soluble proteins, total amino acids and total nitrogen) in five cabbage genotypes. We then examined the settling and oviposition choices of MEAM1 and MED on the five cabbage genotypes, respectively. The settling and oviposition preferences of both MEAM1 and MED were negatively related to the content of total phenolics rather than to the content of glucosinolates or main nutrients. Furthermore, our results showed that MEAM1 ranked the host quality of the cabbage genotypes more accurately than MED. The results at least in part indicate that total phenolics rather than glucosinolates mediate the host choice of B. tabaci MEAM1 and MED on the five cabbage genotypes.

Larvae of a previously undescribed gall midge species have been feeding within malformed flower buds of goji berry Lycium barbarum L. (Solanaceae) in China, preventing fruit development and causing damage to the fruit industry. The new species is named Gephyraulus lycantha Jiao & Kolesik, its morphology is described, the COI mitochondrial gene segment is sequenced, and the biology is outlined. In order to taxonomically accommodate the new gall midge, the scope of the genus Gephyraulus is broadened and now encompasses also species that lack dorso-apical sensoria on the female cercus.

The whitefly, Bemisia tabaci Gennadius, is a major phloem-feeding pest of agricultural crops that is also an important vector of many plant diseases. The B. tabaci Mediterranean (`MED') biotype is a particularly effective vector of Tomato yellow leaf curl virus (TYLCV), a devastating plant pathogen. Although insecticides play an important role in the control of MED and TYLCV, little is known about howTYLCV infection affects MED susceptibility to insecticides. We conducted research addressing how MED susceptibility to flupyradifurone, the first commercially available systemic control agent derived from the butenolide class of insecticides, was affected by TYLCV infection. We first conducted bioassays determining the LC15 and LC50 for control and viruliferous MED feeding on either water- or insecticide-treated plants. We next measured several demographic parameters of control and viruliferous MED exposed to either insecticide- or water-treated plants. TYLCV infection increased MED tolerance of flupyradifurone: the LC15 and LC50 of viruliferous MED were double that of uninfected MED. Viral infection also altered MED demographic responses to flupyradifurone, but in an inconsistent manner. Although the ability of TYLCV and other persistently transmitted viruses to benefit Bemisia via manipulation of host plant defense is well known, this appears to be the first example of virally mediated changes in vector susceptibility to an insecticide.

Host-plant volatiles play vital roles for insects to locate foraging, mating, and oviposition sites in the environment. As one of the devastating invasive forestry pests, Hyphantria cunea causes a great annual loss in China, and understanding its chemical ecology is an important task. The current research was done in terms of chemical analysis, electrophysiology, and behavioral assays on H. cunea to assess its olfactory reception toward host-plant volatiles. A screen of possible common host volatiles was done, targeting on five favored hosts of H. cunea, harvesting six potential bioactive compounds from a total of 78 odorant components. Six types of antennal sensilla were investigated on their distributions on the antennae, and sexual dimorphism was described. H. cunea showed responses to all selected host-related volatiles in electroantennogram tests, and linalyl butyrate elicited the strongest responses. Furthermore, mating rates in adult pairs that are exposed to dibutyl phthalate and phytol have been significantly increased, while oviposition rates and female fecundity were not influenced. The results of the current study provide initial evidence showing that universal host-derived volatile cues are essential for H. cunea moth in terms of mating, which can also provide insights into the development of botanical attractants.

烟粉虱是一种世界性害虫,入侵世界许多地区,其携带的番茄黄化曲叶病毒(Tomato yellow leaf curl virus,TYLCV)给番茄生产造成了严重的损失.烟粉虱的种类繁多,给绿色防控带来许多困难.为了明确烟粉虱的种类,本试验主要对天津周边,还有山东、山西和湖北等省市10个地区不同寄主共16个烟粉虱种群进行了隐种鉴定及系统发育分析.结果表明,其中13个烟粉虱种群只有MED隐种,3个烟粉虱种群中MEAM1和MED隐种共存.MEAM1隐种烟粉虱的同源性高达100％,MED隐种烟粉虱的同源性为99.6％～100％,入侵我国的MED隐种可能起源于地中海西部地区.本研究明确了监测地区烟粉虱隐种及其进化关系,为当地烟粉虱的防控提供了科学依据.

Background: While virus-vector-host interactions have been a major focus of both basic and applied ecological research, little is known about how different levels of plant defense interact with prior herbivory to affect these relationships. We used genetically-modified strains of tomato (Solanum lycopersicum) varying in the jasmonic acid (JA) plant defense pathways to explore how plant defense and prior herbivory affects a plant virus (tomato yellow leaf curl virus, 'TYLCV'), its vector (the whitefly Bemisia tabaci MED), and the host. Results: Virus-free MED preferred low-JA over high-JA plants and had lower fitness on high-JA plants. Viruliferous MED preferred low-JA plants but their survival was unaffected by JA levels. While virus-free MED did not lower plant JA levels, viruliferous MED decreased both JA levels and the expression of JA-related genes. Infestation by viruliferous MED reduced plant JA levels, and TYLCV loads were consistently higher in plants fed upon by viruliferous MED than in plants fed on by virus-free MED. In preference tests, neither virus-free nor viruliferous MED discriminated among JA-varying plants previously exposed to virus-free MED. However, both virus-free and viruliferous MED preferred low-JA plant genotypes when choosing between plants that had both been previously exposed to viruliferous MED. The enhanced preference for low-JA genotypes appears linked to the volatile compound neophytadiene, which was found only in whitefly-infested plants and at concentrations inversely related to plant JA levels. Conclusions: Our findings illustrate how plant defense can interact with prior herbivory to affect both a plant virus and its whitefly vector, and confirm the induction of neophytadiene by lower JA that may prove useful in pest detection and management.

MEAM1 (Middle East-Asia Minor 1, "B" biotype) and MED (Mediterranean, "Q" biotype) are the two most destructive cryptic species of the Bemisia tabaci complex on the planet. Our previous studies have shown that MEAM1 outcompetes MED on cabbage; the underlying mechanism is unknown. In the Brassicaceae family, the glucosinolate-myrosinase defense system plays a crucial role in deterring feeding, inhibiting growth, and causing acute toxicity against a wide range of generalist herbivores. In the present study, we first compared the survival of MEAM1 and MED exposed to sinigrin (a glucosinolate) and myrosinase (an enzyme that degrades glucosinolates); we found that survival of both species was high in response to sinigrin alone but was near zero in response to sinigrin + myrosinase. We then used electropenetrography (electrical penetration graphs, EPG) to assess the feeding behaviors of MEAM1 and MED whiteflies on cabbage. The EPG results revealed that the mean duration of each potential drop (pd, indicating an intracellular puncture) was substantially longer for MED than MEAM1 on cabbage, indicating that the exposure to the toxic hydrolysates of glucosinolate and myrosinase is greater for MED than for MEAM1. We therefore conclude that differences in penetrating behaviors may help explain the different effects of cabbage on MEAM1 and MED whitefly species.