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Plant viruses can facilitate their transmission by modulating the sex ratios of their insect vectors. Previously, we found that exposure to tomato spotted wilt orthotospovirus (TSWV) in the western flower thrips, Frankliniella occidentalis, led to a male-biased sex ratio in the offspring. TSWV, a generalist pathogen with a broad host range, is transmitted primarily by F. occidentalis in a circulative-propagative manner. Here, we integrated proteomic tools with RNAi to comprehensively investigate the genetic basis underlying the shift in vector sex ratio induced by the virus.Proteomic analysis exhibited 104 differentially expressed proteins between F. occidentalis adult males with and without TSWV. The expression of the fiber sheath CABYR-binding-like (FSCB) protein, namely FoFSCB-like, a sperm-specific protein associated with sperm capacitation and motility, was decreased by 46%. The predicted FoFSCB-like protein includes 10 classic Pro-X-X-Pro motifs and 42 phosphorylation sites, which are key features for sperm capacitation. FoFSCB-like expression was gradually increased during the development and peaked at the pupal stage. After exposure to TSWV, FoFSCB-like expression was substantially down-regulated. Nanoparticle-mediated RNAi substantially suppressed FoFSCB-like expression and led to a significant male bias in the offspring.These combined results suggest that down-regulation of FoFSCB-like in virus-exposed thrips leads to a male-biased sex ratio in the offspring. This study not only advances our understanding of virus-vector interactions, but also identifies a potential target for the genetic management of F. occidentalis, the primary vector of TSWV, by manipulating male fertility. © 2022 Society of Chemical Industry.

Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is often used for biological control of small arthropod pests in greenhouse vegetable production systems in Asia. In addition to feeding on arthropod prey, O. sauteri consumes small quantities of plant material. Previous studies demonstrated that tomato plant chemistry confers antixenosis resistance to phloem-feeding whiteflies, but the potential nontarget effects of phytochemicals on the beneficial predator O. sauteri are unknown. Comparison of O. sauteri confined to near-isogenic lines (NILs) of tomatoes producing high levels of flavonoids (NIL-purple hypocotyl; resistant to whiteflies) and low levels of flavonoids (NIL-green hypocotyl; susceptible to whiteflies) revealed that O. sauteri had reduced oviposition, nymphal survival, and development on resistant plants, even if they were also provided with prey that did not feed on the host plant. Moreover, O. sauteri showed a significant ovipositional preference in choice assays, laying significantly more eggs on susceptible than on resistant plants. Molecular gut content analysis using the specific chloroplast trnL gene from tomato confirmed that adult and immature O. sauteri feed on both resistant and susceptible genotypes, and feeding behavior assays revealed that resistance did not affect plant feeding or prey acceptance by O. sauteri adults. These results demonstrate a direct negative effect of phytochemicals on a nontarget beneficial species and indicate that resistance mediated by phytochemicals can affect organisms that do not solely feed on phloem sap. The results also indicate that the mode of action and the potential ecological effects of phytochemical-mediated resistance are broader than previously recognized.

Thermal stress usually leads to excessive production of reactive oxygen species (ROS) in all aerobic organisms. Catalases (CAT) are the key antioxidant enzymes, which act as the first line of defense against ROS in the antioxidant pathway. The highly invasive and widely distributed whitefly Bemisia tabaci MED damages plants by feeding as well as by transmitting many plant viruses. Previous studies have shown that strong adaptability to high temperature helps explain the spread of MED around the world. However, the mechanism underlying high temperature adaptation of this pest is not well understood. In this study, six CAT genes were identified from the MED genome and transcriptome dataset, among which BtCAT1, BtCAT2, and BtCAT3 were found to be highly expressed in adults. The expression of BtCAT1, BtCAT2, or BtCAT3 increased with induction temperature and induction time. The MED was exposed with mean high temperature (30°C or 35°C) and a short-term extremely high temperature (39°C or 41°C) after the silencing of BtCAT1, BtCAT2, or BtCAT3 to significantly increased ROS levels by at least 0.5 times and significantly decreased survival rate and fecundity of MED adults. The ROS level in the treated specimens gradually returned to a normal level after 24 h at 25°C, but the survival rate still declined significantly. Taken together, our results demonstrate that CAT could help B. tabaci adapt to long-term mean high temperatures and short-term extremely high temperatures by eliminating excessive ROS. This article is protected by copyright. All rights reserved.

BACKGROUND Use of RNA interference (RNAi) technology in effective pest management has been explored for decades. Henosepilachna vigintioctopunctata is a major solanaceous crop pest in Asia. In this study, the effects of the RNAi-mediated silencing of clathrin heavy chain in H. vigintioctopunctata were investigated. RESULTS Feeding either the in vitro-synthesized or the bacterially expressed double-stranded RNAs (dsRNAs) significantly impaired the normal physiology of H. vigintioctopunctata instars and adults. However, the bacterially expressed dsHvChc caused higher mortality than the in vitro-synthesized ones in the larvae and adults. Moreover, on evaluating the potential risk of dsHvChc on Propylea japonica, significant transcriptional effects of dsHvChc1 were observed, while the organismal level effects were not significant. On the contrary, dsHvChc2 did not affect P. japonica at either level. A similar test revealed significant transcriptional effects of dsPjChc1 on H. vigintioctopunctata, while staying ineffective at the organismal levels. Conversely, dsPjChc2 did not affect H. vigintioctopunctata at either level. Importantly, no effect of dsPjChc1 exposure on H. vigintioctopunctata suggested that other factors besides the 21-nucleotide (nt) matches between sequences were responsible. Finally, ingestion of dsHvmChc1 derived from H. vigintioctomaculata, containing 265-nt matches with dsHvChc1, caused 100% mortality in H. vigintioctopunctata. CONCLUSIONS We conclude that (i) species with numerous 21-nt matches in homologous genes are more likely to be susceptible to dsRNA; (ii) dsRNA can be safely designed to avoid negative effects on non-target organisms at both transcriptional and organismal levels; (iii) HvChc can be used as an efficient RNAi target gene to effectively manage H. vigintioctopunctata.

Backgroud Cardinium symbiont is a maternally inherited bacterial endosymbiont and widely spreads in arthropods including Bemisia tabaci (Hemiptera: Aleyrodidae). However, the potential role of Cardinium played in the biology of their hosts is largely unknown. In two genetic lines (i.e. LS and SG lines) of B. tabaci MED, collected from different locations in China, we tested the effects of Cardinium on the performance of the host whitefly under a constant high temperature (31 °C) using the age-stage two-sex life table method, and explored the genes influenced by Cardinium-infection by RNA-sequencing. Results We found that Cardinium did provide protection of B. tabaci against heat stress under 31 °C. However, there was a significant connection between Cardinium-infection and whitefly genetic backgrounds. Performance revealed that Cardinium infection can increase the longevity of both female and male adults and oviposition periods in both lines, but it also conferred benefits of fecundity and pre-adult period to LS line. Additionally, the population parameters such as intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) demonstrated that Cardinium infection conferred fitness benefits to LS line but not to SG line. Transcriptome analysis indicated that several genes related to homeostasis and metamorphosis such as ubiquitin-related genes were highly expressed in Cardinium-infected B. tabaci. Conclusion The research provided the first evidence that Cardinium can increase the thermal tolerance of whitefly, which may be associated with host genetic background.

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. © 2021 Society of Chemical Industry.

RNA interference (RNAi) has emerged as a powerful tool for developing novel management strategies for controlling insect pests. The 28-spotted ladybeetle, Henosepilachna vigintioctopunctata is one of the most important pests attacking solanaceous plants in Asia. In this study, the potential of dietary RNAi to manage H. vigintioctopunctata was investigated using both in vitro synthesized and bacterially expressed double-stranded RNAs (dsRNAs) of HvvATPase A and HvvATPase E. The expression levels of HvvATPase A and HvvATPase E were higher in Malpighian tubules than in other tissue types. The silencing of HvvATPase A and HvvATPase E led to significant mortality in H. vigintioctopunctata larvae. In addition, the ingestion of HvvATPase A and HvvATPase E significantly deterred feeding behavior and subsequently arrested the development of H. vigintioctopunctata. Notably, the bacterially expressed dsRNAs consistently caused higher mortality in larvae and adults. Finally, the nontarget effects of the dsRNAs of H. vigintioctopunctata on the predatory ladybeetle Propylaea japonica were evaluated. P. japonica 1st instar larvae were administered vATPase A and vATPase E dsRNAs from H. vigintioctopunctata and P. japonica under the worst-case scenario, in which dsGFP served as negative control. There were significant effects of dsHvvATPase A on P. japonica at the transcriptional level but not at the organismal level, whereas dsHvvATPase E did not effect P. japonica at either the transcriptional or the organismal level. Collectively, the results of the study suggest that HvvATPase A and HvvATPase E can act as novel molecular targets for the control of H. vigintioctopunctata.

The invasive pest whitefly (Bemisia tabaci) is a complex species, of which Middle East-Minor Asia 1 (MEAM1) and Mediterranean (MED) are the two most damaging members. Previous research showed that cabbage is frequently infested with MEAM1 but seldomly with MED, and this difference in performance is associated with glucosinolate (GS) content. Some insects can modify GS using glucosinolate sulfatase (SULF), the activity of which is regulated by sulfatase modifying factor 1 (SUMF1); therefore, to increase our understanding of different performances of MEAM1 and MED on cabbage plants, we identified and compared nine putative SULFs and one SUMF in MEAM1 and MED. We found that the lengths of two genes, BtSulf2 and BtSulf4, differed between MEAM1 and MED. The messenger RNA levels of BtSulf4 increased more than 20-fold after MEAM1 and MED adults were exposed to GS, but BtSulf2 expression was only induced by GS in MEAM1. Knockdown of BtSulf2 and BtSulf4 in MEAM1 resulted in a substantial increase in the mortality of GS-treated adults but not in MED. These results indicate that differences in BtSulf2 and BtSulf4 sequences and/or expression may explain why MEAM1 performs better than MED on cabbage. Our results provide a basis for future functional research on SULF and SUMF in B. tabaci.

Green leaf volatiles (GLVs) can induce defence priming, that is, can enable plants to respond faster or more strongly to future stress. The effects of priming by GLVs on defence against insect herbivores and pathogens have been investigated, but little is known about the potential of GLVs to prime crops against virus transmission by vector insects. Here, we tested the hypothesis that exposure to the GLV Z-3-hexenol (Z-3-HOL) can prime tomato (Solanum lycopersicum) for an enhanced defence against subsequent Tomato yellow leaf curl virus (TYLCV) transmission by the whitefly Bemisia tabaci. Bioassays showed that Z-3-HOL priming reduced subsequent plant susceptibility to TYLCV transmission by whiteflies. Z-3-HOL treatment increased transcripts of jasmonic acid (JA) biosynthetic genes and increased whitefly-induced transcripts of salicylic acid (SA) biosynthetic genes in plants. Using chemical inducers, transgenics and mutants, we demonstrated that induction of JA reduced whitefly settling and successful whitefly inoculation, while induction of SA reduced TYLCV transmission by whiteflies. Defence gene transcripts and flavonoid levels were enhanced when whiteflies fed on Z-3-HOL-treated plants. Moreover, Z-3-HOL treatment reduced the negative impact of whitefly infestation on tomato growth. These findings suggest that Z-3-HOL priming may be a valuable tool for improving management of insect-transmitted plant viruses.

RNA interference (RNAi) techniques have emerged as powerful tools that facilitate development of novel management strategies for insect pests, such as Henosepilachna vigintioctopunctata (Coleoptera: Coccinellidae), which is a major pest of solanaceous plants in Asia. In this study, the potential of oral delivery of in vitro-synthesized and bacterially expressed double-stranded H. vigintioctopunctata lesswright (lwr) gene (dsHvlwr) to manage of H. vigintioctopunctata was investigated. Our results showed that the gene Hvlwr had a 480-bp open reading frame and encoded a 160-amino acid protein. Hvlwr expression levels were greater in the fat body than other tissue types. Hvlwr silencing led to greater H. vigintioctopunctata mortality rates and appeared to be time- and partially dose-dependent, likely as a result of the number of hemocytes increasing with dsRNA concentration, but decreasing with time. Bacterially expressed dsHvlwr that was applied to leaf discs caused 88%, 66%, and 36% mortality in 1st instars, 3rd instars, and adults after 10, 10, and 14 d, respectively; when applied to living plants, there was greater mortality in 1st and 3rd instars, but there was no effect on adults. Furthermore, dsHvlwr led to improved plant protection against H. vigintioctopunctata. Our study shows an effective dietary RNAi response in H. vigintioctopunctata and that Hvlwr is a promising RNAi target gene for control of this pest species.

The greenhouse whitefly, Trialeurodes vaporariorum Westwood, is an agricultural pest of global importance. Here we report a 787-Mb high-quality draft genome sequence of T. vaporariorum assembled from PacBio long reads and Hi-C chromatin interaction maps, which has scaffold and contig N50 lengths of 70 Mb and 500 kb, respectively, and contains 18,275 protein-coding genes. About 98.8% of the assembled contigs were placed onto the 11 T. vaporariorum chromosomes. Comparative genomic analysis reveals significantly expanded gene families such as aspartyl proteases in T. vaporariorum compared to Bemisia tabaci Mediterranean (MED) and Middle East-Asia Minor 1 (MEAM1). Furthermore, the cytochrome CYP6 subfamily shows significant expansion in T. vaporariorum and several genes in this subfamily display developmental stage-specific expression patterns. The high-quality T. vaporariorum genome provides a valuable resource for research in a broad range of areas such as fundamental molecular ecology, insect-plant/insect-microorganism or virus interactions and pest resistance 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.

Background RNA interference (RNAi) is a potential tool for plant protection against insect pests. The great challenge for effective pest control using RNAi in the field is the development of efficient and reliable methods for the production and delivery of double-stranded RNA (dsRNA). Results In the present study, we investigated the potential of feeding in vitro synthesized or bacterially expressed dsRNA to populations of the 28-spotted ladybeetle Henosepilachna vigintioctopunctata as a method of biological pest control. Ingestion of in vitro synthesized dsHvRPS18 or dsHvRPL13 led to significant down-regulation of the ribosomal protein-encoding genes HvRPS18 and HvRPL13, respectively, and significantly decreased the survival of H. vigintioctopunctata. Such silencing of HvRPS18 or HvRPL13 expression appeared to be partially dose-dependent and also inhibited the growth of H. vigintioctopunctata and significantly suppressed the expression of digestive enzyme-related genes. Finally, ingestion of bacterially expressed dsHvRPS18 or dsHvRPL13 induced significant mortality in the first and third instars, and in adults. Conclusion The effectiveness of RNAi-based gene silencing in H. vigintioctopunctata provides a powerful reverse genetic tool for the functional annotation of its genes. This study demonstrates that HvRPS18 and HvRPL13 represent candidate genes for RNAi-based biological control of H. vigintioctopunctata. © 2020 Society of Chemical Industry.

Background Nuclear receptors (NRs) play an essential role in diverse biological processes, such as insect metamorphosis. Here, transcriptome analysis and functional studies were used to determine whether NRs are involved in metamorphosis of whitefly Bemisia tabaci Q, a serious pest to crops, and to find some potential insecticide targets. Results Twenty NRs were identified in the Bemisia tabaci Q genome and categorized into the NR0-NR6 subfamilies. The phylogenetic tree of NRs from Bemisia tabaci Q and other representative species was constructed, which provided evolutionary insight into their genetic distances. The results of spatiotemporal gene expression indicated that the majority of NR gene expression was higher in the head than the abdomen and higher in eggs than adults. Further functional analysis using RNA interference (RNAi) showed that NR genes play an important role in Bemisia tabaci Q pupation and eclosion. With respect to high mortality and effects on growth, this was reflected in the unable to become pupa when the third-stage nymph treated with double-stranded RNA (dsRNA) and the developmental time delay (4-7 days) when pupae were treated with dsRNA for the 12 NR genes during molting compared with the development time in the control. Conclusion This study provides insight into NR functions during the metamorphosis stages of Bemisia tabaci Q. Several candidate genes could be potential insecticide targets for whitefly pest control due to their important roles in insect development. © 2020 Society of Chemical Industry.

Background Rapid evolution of pest resistance has seriously threatened the sustainable use of Bacillus thuringiensis (Bt). The diamondback moth, Plutella xylostella (L.), is the first pest to develop resistance to Bt biopesticides in the open field, which renders it an excellent model to explore the molecular basis of Bt resistance in insects. Our previous midgut transcriptome and RNA-Seq profiles showed that the P-glycoprotein gene PxABCB1 was down-regulated in two Cry1Ac-resistant P. xylostella strains, suggesting its potential involvement in Cry1Ac resistance in P. xylostella. Results In this study, the bona fide full-length cDNA sequence of the PxABCB1 gene was cloned and analyzed, and the expression of the PxABCB1 gene was detected in all tissues and developmental stages, with the highest expression in midgut tissue and the female adult stage. Although no consistent non-synonymous mutations were identified between the susceptible and resistant strains, PxABCB1 gene expression was remarkably decreased in all resistant strains, and the association was further validated by Cry1Ac selection in the moderately resistant SZ-R strain. Moreover, knockdown of the PxABCB1 gene expression resulted in significantly reduced larval susceptibility to Cry1Ac toxin in the DBM1Ac-S strain, and decreased expression of the PxABCB1 gene was tightly linked to Cry1Ac resistance in P. xylostella. Conclusion Our results demonstrated that down-regulation of the PxABCB1 gene is associated with both laboratory-selected and field-evolved Cry1Ac resistance in P. xylostella. This knowledge will be conducive to further elucidating the complicated molecular basis of Bt resistance and developing new insect resistance management tactics. © 2019 Society of Chemical Industry.

Background As a method of RNA-mediated gene silencing, RNA interference (RNAi) is a useful reverse genetic tool with which to study gene function, and holds great promise for pest management. Bemisia tabaci is a cosmopolitan pest that causes extensive damage to crops. The mechanism underlying RNAi efficiency in B. tabaci is not well known. We identified and analyzed candidate genes in the RNAi pathway to understand the RNAi mechanism and provide a basis for the application of RNAi in pest management. Results We identified 33 genes putatively involved in the RNAi pathway from the B. tabaci Q genome. Phylogenetic and structural analyses confirmed the characteristics of these genes. Furthermore, quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and transcriptomic analysis profiled gene expression patterns during different developmental stages. Gene expression levels estimated by qRT-PCR and RNA-seq analyses were significantly correlated. Moreover, gene functions were verified by RNAi. When accompanied by knockdown of AGO2, Dicer2 and Sid1, the efficiency of CYP6DB3 RNAi decreased correspondingly. Conclusion In this study, we annotated and validated genes involved in B. tabaci RNAi. A better understanding of the building blocks of the RNAi process in B. tabaci facilitates integration of this novel biotechnology into the management of this emerging pest, either directly or indirectly. © 2019 Society of Chemical Industry.

Odorant binding proteins (OBPs) and chemosensory proteins (CSPs) play essential roles in insect chemosensory recognition. Here, we identified nine OBPs and nine CSPs from the Myzus persicae transcriptome and genome. Genomic structure analysis showed that the number and length of the introns are much higher, and this appears to be a unique feature of aphid OBP genes. Three M. persicae OBP genes (OBP3/7/8) as well as CSP1/4/6, CSP2/9 and CSP5/8 are tandem arrayed in the genome. Phylogenetic analyses of five different aphid species suggest that aphid OBPs and CSPs are conserved in single copy across all aphids (with occasional losses), indicating that each OBP and CSP class evolved from a single gene in the common ancestor of aphids without subsequent duplication. Motif pattern analysis revealed that aphid OBP and CSP motifs are highly conserved, and this could suggest the conserved functions of aphid OBPs and CSPs. Three OBPs (MperOBP6/7/10) are expressed antennae specifically, and five OBPs (MperOBP2/4/5/8/9) are expressed antennae enriched, consistent with their putative olfactory roles. M. persicae CSPs showed much broader expression profiles in nonsensory organs than OBPs. None of the nine MperCSPs were found to be antennae specific, but five of them (MperCSP1/2/4/5/6) showed higher expression levels in the legs than in other tissues. MperCSP10 mainly expressed in the antennae and legs. The broad and diverse expression patterns of M. persicae CSPs suggest their multifunctions in olfactory perception, development and other processes.

The tricarboxylic acid (TCA) cycle is one of the canonical energy pathways of living systems, as well as being an example of a pathway in which dynamic enzyme assemblies, or metabolons, are well characterized. The role of the enzymes have been the subject of saturated transgenesis approaches, whereby the expression of the constituent enzymes were reduced or knocked out in order to ascertain their in vivo function. Some of the resultant plants exhibited improved photosynthesis and plant growth, under controlled greenhouse conditions. In addition, overexpression of the endogenous genes, or heterologous forms of a number of the enzymes, has been carried out in tomato fruit and the roots of a range of species, and in some instances improvement in fruit yield and postharvest properties and plant performance, under nutrient limitation, have been reported, respectively. Given a number of variants, in nature, we discuss possible synthetic approaches involving introducing these variants, or at least a subset of them, into plants. We additionally discuss the likely consequences of introducing synthetic metabolons, wherein certain pairs of reactions are artificially permanently assembled into plants, and speculate as to future strategies to further improve plant productivity by manipulation of the core metabolic pathway.

In C4 photosynthesis, pyruvate orthophosphate dikinase (PPDK) catalyzes the regeneration of phosphoenolpyruvate in the carbon shuttle pathway. Although the biochemical function of PPDK in maize is well characterized, a genetic analysis of PPDK has not been reported. In this study, we use the maize transposable elements Mutator and Ds to generate multiple mutant alleles of PPDK. Loss-of-function mutants are seedling lethal, even when plants were grown under 2% CO2 , and they show very low capacity for CO2 assimilation, indicating C4 photosynthesis is essential in maize. Using RNA-seq and GC-MS technologies, we examined the transcriptional and metabolic responses to a deficiency in PPDK activity. These results indicate loss of PPDK results in downregulation of gene expression of enzymes of the C4 cycle, the Calvin cycle, and components of photochemistry. Furthermore, the loss of PPDK did not change Kranz anatomy, indicating that this metabolic defect in the C4 cycle did not impinge on the morphological differentiation of C4 characters. However, sugar metabolism and nitrogen utilization were altered in the mutants. An interaction between light intensity and genotype was also detected from transcriptome profiling, suggesting altered transcriptional and metabolic responses to environmental and endogenous signals in the PPDK mutants.

Bemisia tabaci (Gennadius) is an important agricultural pest with a worldwide distribution. Although B. tabaci is known to have a unique haplodiploid reproductive strategy, its sex determination mechanism is largely unknown. In this study, we cloned the full-length sequence of B. tabaci doublesex (Btdsx) and found that Btdsx has 28 splicing isoforms. We found two new splicing isoforms of transformer 2 (Bttra2), which encode two proteins. We also confirmed that both genes lack sex-specific splicing isoforms. Real-time quantitative PCR analysis showed that the expression of Btdsx and Bttra2 is higher in males than in females. RNA interference of Bttra2 affected the expression of Btdsx and vice versa. Furthermore, silencing of Bttra2 or Btdsx caused malformation of the male genitalia (anal style). It did not affect the female phenotype, but reduced the expression of vitellogenin gene in females. These results indicate that Btdsx is associated with sex determination in B. tabaci and that Btdsx and Bttra2 affect each other and are important for male genitalia formation. In addition to increasing our understanding of the roles of dsx and tra2 in the sex determination of B. tabaci, the results will be useful for studies of sex determination in other haplodiploid species.

Odorant‐binding proteins (OBPs) and chemosensory proteins (CSPs) of insects are thought to play roles in olfactory recognition affecting host choice, copulation, reproduction and other behaviors. Previous descriptions of OBPs and CSPs in the whitefly Bemisia tabaci often provided no or incomplete genetic information. In this study, we present a genome‐wide and transcriptome‐wide investigation of the OBPs and CSPs in B. tabaci MEAM1 (Middle East‐Asia Minor1 species). Eight OBP and 19 CSP genes were identified that covered all previous sequences. Phylogenetic analyses showed that the CSP genes had a lineage‐specific expansion (BtabBCSP1, BtabBCSP3, BtabBCSP13, BtabBCSP17, BtabBCSP18 and BtabBCSP19). Expression profiling of OBPs and CSPs by transcriptome sequencing and quantitative real‐time polymerase chain reaction (qPCR) revealed that expression patterns differed among developmental stages of B. tabaci MEAM1. Five OBP genes and 11 CSP genes significantly differed between males and females; four of the 19 CSP genes were highly expressed in adults, while two were highly expressed in nymphs. The expression profiles of the OBP and CSP genes in different tissues of B. tabaci MEAM1 adults were analyzed by qPCR. Four OBP genes found in B. tabaci MEAM1 were highly expressed in the head. Conversely, only two CSPs were enriched in the head, while the other six CSPs were specifically expressed in other tissues. Our results provide a foundation for future research on OBPs and CSPs in B. tabaci.

The diamondback moth, Plutella xylostella (L.) is the most widely distributed pest of Brassica vegetables. Control of P. xylostella has relied on insecticides and it has developed resistance to most insecticides. Although research has clarified the resistance status and mechanisms in northern China, little work has been conducted on long-term population dynamics in the regions' key vegetable growing areas. We reviewed and summarized the history of P. xylostella field management practices in northern China (Haidian, Changping, Xuanhua and Zhangbei). Moths were caught in pheromone traps throughout the cropping season and P. xylostella phenology and the general trends in abundance was analyzed using DYMEX modelling software. The initial input in the spring determined population size in all years. The seasonal phenology and variation in abundance in most years and sites was simulated suggesting that the suitable climate creates the conditions for population outbreaks, and growers' actual management level (spraying and crop hygiene) influenced population abundance. Based on temperatures and using the timing of the initial peak in pheromone trap captures as a biofix, the timing of emergence of the next generation can be forecast, and more scouting and effective regional management strategies against this pest can be developed.

Leaf damage caused by herbivore feeding often triggers induced resistance in plants. However, some herbivores can take advantage of the resulting metabolic changes in host plants and may even manipulate plant resistance, leading to a phenomenon known as induced susceptibility. Previous work has shown that feeding by the whitefly Bemisia tabaci can reduce tomato Solanum lycopersicum resistance and that whiteflies tended to aggregate on infested plants. However, metabolomic changes in the plant and associated whitefly behavioural responses underlying this phenomenon remain poorly understood. We, therefore, investigated how B. tabaci infestation affects host physiology and the preference and performance of conspecific feeders. Bemisia tabaci adults exhibited consistent behavioural preferences for plants that experienced actual and simulated herbivory by conspecifics (consistent with observed effects on whitefly performance), but not for plants that were only mechanically wounded. Leaf volatiles and extracts of B. tabaci‐infested plants showed altered terpenoid and flavonoid profiles. Manipulative behavioural experiments indicated that suppression of the monoterpenes α‐phellandrene and α‐terpinene and of flavonoids by B. tabaci infestation influenced the foraging and oviposition preferences of conspecifics. These findings document key metabolic changes in plants exhibiting induced susceptibility and demonstrate their role in mediating herbivore foraging behaviour and aggregation on susceptible plants, thereby providing new insight into a relatively unexplored aspect of plant–herbivore interactions. A plain language summary is available for this article.

The performance of herbivorous insects is greatly affected by host chemical defenses and nutritional quality. Some herbivores have developed the ability to manipulate plant defenses via signaling pathways. It is currently unclear, however, whether a herbivore can benefit by simultaneously reducing plant defenses and enhancing plant nutritional quality. Here, we show that the better performance of the whitefly Bemisia tabaci Middle East-Asia Minor 1 (MEAM1; formerly the “B” biotype) than Mediterranean (MED; formerly the “Q” biotype) on cabbage is associated with a suppression of glucosinolate (GS) content and an increase in amino acid supply in MEAM1-infested cabbage compared with MED-infested cabbage. MEAM1 had higher survival, higher fecundity, higher intrinsic rate of increase (rm), a longer life span, and a shorter developmental time than MED on cabbage plants. Amino acid content was higher in cabbage infested with MEAM1 than MED. Although infestation by either biotype decreased the levels of total GS, aliphatic GS, glucoiberin, sinigrin, glucobrassicin, and 4OH-glucobrassicin, and the expression of related genes in cabbage, MED infestation increased the levels of 4ME-glucobrassicin, neoglucobrassicin, progoitrin, and glucoraphanin. The GS content and expression of GS-related genes were higher in cabbage infested with MED than with MEAM1. Our results suggest that MEAM1 performs better than MED on cabbage by manipulating host defenses and nutritional quality.

In eukaryotes, mechanisms such as alternative splicing (AS) and alternative translation initiation (ATI) contribute to organismal protein diversity. Specifically, splicing factors play crucial roles in responses to environment and development cues; however, the underlying mechanisms are not well investigated in plants. Here, we report the parallel employment of short-read RNA sequencing, single molecule long-read sequencing and proteomic identification to unravel AS isoforms and previously unannotated proteins in response to abscisic acid (ABA) treatment. Combining the data from the two sequencing methods, approximately 83.4% of intron-containing genes were alternatively spliced. Two AS types, which are referred to as alternative first exon (AFE) and alternative last exon (ALE), were more abundant than intron retention (IR); however, by contrast to AS events detected under normal conditions, differentially expressed AS isoforms were more likely to be translated. ABA extensively affects the AS pattern, indicated by the increasing number of non-conventional splicing sites. This work also identified thousands of unannotated peptides and proteins by ATI based on mass spectrometry and a virtual peptide library deduced from both strands of coding regions within the Arabidopsis genome. The results enhance our understanding of AS and alternative translation mechanisms under normal conditions, and in response to ABA treatment.

Summary Although many vector-borne plant pathogens can alter vector behaviour to the pathogen's benefit, how plants might counter such manipulation is unknown. In the Tomato yellow leaf curl virus (‘TYLCV’)–Bemisia tabaci–tomato interaction, TYLCV-mediated changes in Bemisia feeding improves viral uptake and transmission. We tested how jasmonic acid (‘JA’), a central regulator of plant antiherbivore defences, affected the ability of TYLCV to (A) manipulate Bemisia behaviour; and (B) infect plants. Viruliferous Bemisia fed much more than virus-free whiteflies on JA-deficient plants, more than virus-free whiteflies on controls, and similarly on high-JA plants. When TYLCV was transmitted via whiteflies, infection levels were lower in high-JA plants relative to JA-deficient and control plants. When TYLCV was transmitted via direct injection, JA-overexpressed and JA-deficient plants had similar infection levels. The JA-mediated cessation of vector manipulation thus reduced infection and lessened pathogen impact. The presence of the JA pathway in many plant species suggests that similar interactions may be widespread in nature. A lay summary is available for this article.

Odorant receptors (ORs) expressed in the antennae of parasitoid wasps are responsible for detection of various lipophilic airborne molecules. In the present study, 107 novel OR genes were identified from Microplitis mediator antennal transcriptome data. Phylogenetic analysis of the set of OR genes from M. mediator and Microplitis demolitor revealed that M. mediator OR (MmedOR) genes can be classified into different subfamilies, and the majority of MmedORs in each subfamily shared high sequence identities and clear orthologous relationships to M. demolitor ORs. Within a subfamily, six MmedOR genes, MmedOR98, 124, 125, 126, 131 and 155, shared a similar gene structure and were tightly linked in the genome. To evaluate whether the clustered MmedOR genes share common regulatory features, the transcription profile and expression characteristics of the six closely related OR genes were investigated in M. mediator. Rapid amplification of cDNA ends-PCR experiments revealed that the OR genes within the cluster were transcribed as single mRNAs, and a bicistronic mRNA for two adjacent genes (MmedOR124 and MmedOR98) was also detected in female antennae by reverse transcription PCR. In situ hybridization experiments indicated that each OR gene within the cluster was expressed in a different number of cells. Moreover, there was no co-expression of the two highly related OR genes, MmedOR124 and MmedOR98, which appeared to be individually expressed in a distinct population of neurons. Overall, there were distinct expression profiles of closely related MmedOR genes from the same cluster in M. mediator. These data provide a basic understanding of the olfactory coding in parasitoid wasps.

Sex determination genes are important regulators of reproduction as well as of the development of both behavioural and morphological sex characteristics. The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is an emerging insect pest worldwide. The recent release of the genome sequence of the highly invasive B. tabaciQ/MED allows us to investigate the mechanisms and genes involved in sex determination. The combined genome and transcriptome-wide analyses identified 26 genes putatively associated with sex determination in B. tabaciQ/MED. The temporal profiles of these genes exhibited a consistent expression pattern at all B. tabaci developmental stages: the highest transcript levels were detected in eggs (21 genes, 80.8%) and the lowest in adults (24 genes, 92.3%). The expression pattern was further validated by quantitative real-time reverse transcription PCR analysis. Alternative splicing analysis found that (1) da and mle have sex-specific isoforms in B. tabaci adults, whereas Imp does not, and (2) exon skipping is a common splicing mechanism involved in B. tabaci sex determination. This research provides a comprehensive list of genes involved in B. tabaci sex determination and provides an opportunity to further understand the mechanisms underlying sex determination in a globally invasive insect pest that reproduces both sexually and asexually.

Plants frequently engage in simultaneous interactions with diverse classes of biotic antagonists. Differential induction of plant defence pathways by these antagonists, and interactions between pathways, can have important ecological implications; however, these effects are currently not well understood. We explored how Tomato yellow leaf curl virus (TYLCV) influenced the performance of its vector (Bemisia tabaci) and a non-vector herbivore (Tetranychus urticae) occurring separately or together on tomato plants (Solanum lycopersicum). TYLCV enhanced the performance of B. tabaci, although this effect was statistically significant only in the absence of T. urticae, which adversely affected B. tabaci performance regardless of infection status. In contrast, the performance of T. urticae was enhanced (only) by the combined presence of TYLCV and B. tabaci. Analyses of phytohormone levels and defence gene expression in wild-type tomatoes and various plant-defence mutants indicate that the enhancement of herbivore performance (for each species) entails the disruption of downstream defences in the jasmonic acid (JA) pathway. For T. urticae, this disruption appears to involve antagonistic effects of salicylic acid (SA), which is cumulatively induced to high levels by B. tabaci and TYLCV. In contrast, TYLCV was found to suppress JA-mediated responses to B. tabaci via mechanisms independent of SA.

OBJECTIVE This study aimed to compare the efficacy and safety of two different treatments of paravalvular leak (PVL). BACKGROUND PVL is a common complication after surgical valve replacement. Re-operation is associated with high mortality, morbidity, and risk of re-leak. Catheter-based repair has emerged as a promising new therapy. METHODS AND RESULTS Eighty-seven consecutive patients with symptomatic PVL received either transcatheter (n = 46) or surgical (n = 41) treatment at Shanghai Chest Hospital between January 2009 and December 2015.The procedural and clinical success rates were similar between the transcatheter group and the surgical group (82.6 vs. 90.2%; P = 0.30; and 69.5 vs. 73.0%; P = 0.71, respectively). There were fewer in-hospital total major adverse events in the transcatheter group (56.09 vs. 17.39%; P

While the management of biological invasions is often characterized by a series of single-specieg decisions, invasive species exist within larger food webs. These biotic interactions can alter the impact of control/eradication programs and may cause suppression efforts to inadvertently facilitate invasion spread and impact. We document the rapid replacement of the invasive Bemisia Middle East-Asia Minor I (MEAM1) cryptic biotype by the cryptic Mediterranean (MED) biotype throughout China and demonstrate that MED is more tolerant of insecticides and a better vector of tomato yellow leaf curl virus (TYLCV) than MEAMJ. While MEAM1 usually excludes MED under natural conditions, insecticide application reverses the MEAM1-MED competitive hierarchy and allows MED to exclude MEAMI. The insecticide-mediated success of MED has led to TYLCV outbreaks throughout China. Our work strongly supports the hypothesis that insecticide use in China reverses the MEAMl-MED competitive hierarchy and allows MED to displace MEAM1 in managed landscapes. By promoting the dominance of a Bemisia species that is a competent viral vector, insecticides thus increase the spread and impact of TYLCV in heterogeneous agroecosystems.

BACKGROUND Resistance to Bacillus thuringiensis (Bt) formulations in insects may be associated with fitness costs. A lack of costs enables resistance alleles to persist, which may contribute to the rapid development and spread of resistance in populations. RESULTS To assess the fitness costs associated with Bt Cry1Ac resistance in Plutella xylostella, life tables were constructed for a near-isogenic resistant strain (NIL-R) and a susceptible strain in this study. No fitness costs associated with Cry1Ac resistance in NIL-R were detected, based on the duration of egg and larval stages, the survival of eggs and larvae, adult longevity, fecundity, net reproductive rate, gross reproduction rate, finite rate of increase and mean generation time. Based on log dose–probit lines, resistance in NIL-R is incompletely recessive and results from a single, autosomal, recessive locus; the degree of dominance was estimated to be −0.74 and −0.71 for F1 (resistant ♀ × susceptible ♂) and F1′ (susceptible ♀ × resistant ♂) progeny respectively. CONCLUSION Assessment of near-isogenic Cry1Ac-resistant and Cry1Ac-susceptible strains of P. xylostella indicated that resistance is not accompanied with fitness costs, and that resistance is incompletely recessive. These findings should be useful in managing the development of Bt Cry1Ac resistance. © 2015 Society of Chemical Industry

Summary Maternally inherited bacterial symbionts are present in many, if not most, insect species. While there is rapidly accumulating evidence that facultative, heritable symbionts often protect insect hosts from natural enemies, there have been few clear examples where facultative symbionts mediate herbivore–plant interactions. The phloem-feeding whitefly, Bemisia tabaci, is a major agricultural pest that frequently harbours facultative symbionts, including Hamiltonella defensa. While H. defensa and other facultative symbionts have been shown to improve whitefly performance on particular food plants, no direct and specific roles for symbiont-mediated interactions with food plants have been identified. Here, we conducted a series of assays to determine whether infection with H. defensa improved whitefly performance on tomato (Solanum lycopersicum) and whether this benefit was associated with symbiont effects on induced plant defences. Finally, we tested whether impacts on induced defences involved in the modulation of a salivary factor. The downregulation of plant defences was associated with increased whitefly fecundity and survival. Feeding by H. defensa-infected whiteflies suppressed JA and JA-related anti-herbivore-induced defences in tomato relative to uninfected controls. That saliva-only treatments of damaged tomato leaves from H. defensa-infected whiteflies suppressed induced plant defences compared to saliva from uninfected controls, suggesting that elicitors in saliva were responsible. Characterization of the putative salivary factor(s) revealed they are likely small (< 3-kDa) and nonproteinaceous. Interestingly, suppression of defences was not observed in SA-deficient NahG plants, indicating that suppression of JA-regulated defences depends on the SA signalling pathway. This finding reveals an intriguing example of the crosstalk between SA and JA signalling pathways and suggests that infection with facultative symbionts can result in the manipulation of induced plant defences to the benefit of the insect host and heritable symbiont. Our results show that the bacterial symbiont H. defensa mediates whitefly–plant interactions by suppressing induced plant defences in tomato. This finding is among the first showing a direct role for facultative symbionts in mediating plant–herbivore interactions and demonstrates a novel tactic for insect herbivores to circumvent plant defences. Symbiont-mediated suppression of plant defences may enhance the deleterious effects of insect pests feeding on important crops.

Diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is one of the most destructive pests in Brassicaceae crops, such as Chinese cabbage (Brassica rapa L.). It is rapidly developing resistance to abamectin, the dominant insecticide utilized in controlling P. xylostella in China and other southeastern Asian countries. The target of abamectin, the alpha subunit of glutamate-gated chloride channel (GluClα), is thought to be involved in the development of abamectin resistance in nematodes and insects. This study investigated variants of GluClα in both abamectin-susceptible and resistant strains of P. xylostella. A comparison of the PxGluClα sequences revealed three variants, including a 63-bp substitution, a 36-bp deletion, and a 65-bp insertion. The frequency of the 36-bp deletion was much higher in the abamectin-resistant strain compared to the susceptible strain, whereas the 63-bp substitution and 65-bp insertion showed no significant difference between the resistant and susceptible strains. The in vitro expression of PxGluClα (with or without the 36-bp deletion) in Xenopus laevis (Daudin) oocytes indicated that PxGluClα with the 36-bp deletion was less sensitive to both glutamate and abamectin compared to the wild-type PxGluClα. These findings suggest that the variant 36-bp deletion in PxGluClα may confer abamectin resistance in P. xylostella after continuous abamectin selection, providing new insights into the management of this pest and contributing to the development of new reagents for pest control.

Changes in carbon flow and sink/source activities can affect floral, architectural, and reproductive traits of plants. In potato, overexpression (OE) of the purple acid phosphatase 2 of Arabidopsis (AtPAP2) resulted in earlier flowering, faster growth rate, increased tubers and tuber starch content, and higher photosynthesis rate. There was a significant change in sucrose, glucose and fructose levels in leaves, phloem and sink biomass of the OE lines, consistent with an increased expression of sucrose transporter 1 (StSUT1). Furthermore, the expression levels and enzyme activity of sucrose-phosphate synthase (SPS) were also significantly increased in the OE lines. These findings strongly suggest that higher carbon supply from the source and improved sink strength can improve potato tuber yield. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

BACKGROUND The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most invasive and destructive pests of field crops worldwide. The sibling species B and Q are the two most damaging members of the B. tabaci species complex. That Q is more resistant than B to many insecticides has been well documented. Over the last decade, Q has gradually displaced B and has become the dominant form of B. tabaci in field agricultural systems in most parts of China. To help understand the differences in insecticide resistance, the activities and gene expression profiles of detoxification enzymes in B. tabaci B and Q were investigated. RESULTS The activity of P450 towards 7-ethoxycoumarin was significantly higher (1.46-fold higher) in Q than in B. The expression of 43 of 65 P450 genes was higher (>1-fold) in Q than in B, and expression for eight P450 genes was more than 50-fold greater in Q than in B. The increased expression of selected P450 genes in Q relative to B was confirmed with two other B strains and two other Q strains. On the other hand, carboxylesterase (CarE) activity was significantly lower (0.71-fold lower) in Q than in B; the Km value of CarE was significantly lower in B than in Q, but the opposite was true for the Vmax value of CarE. Glutathione S-transferase activity and values of Km and Vmax did not differ between B and Q. CONCLUSION Enhanced metabolic detoxification of insecticides by P450s may be an important reason why B. tabaci Q is more resistant than B. tabaci B to insecticides. © 2014 Society of Chemical Industry

B and Q are two putative species of the Bemisia tabaci complex (Hemiptera: Aleyrodidae), and are among the most invasive and destructive pests of crops and horticultural plants worldwide. In China, Q predominates and is displacing B. Although researchers have proposed that the higher capacity of Q to utilize host plants plays an important role in its replacement of B, there are few relevant field surveys and experimental studies. The difference in host assessment between B and Q in multiple-choice rather than in no-choice situations may be essential to understanding the displacement. Here, we compared settling and oviposition preferences, and adult and nymph performance, for the putative species B and Q of the B. tabaci complex on three common host species: poinsettia [Euphorbia pulcherrima Wild. ex Klotsch (Euphorbiaceae)], cotton [Gossypium hirsutum L. (Malvaceae)], and cabbage [Brassica oleracea L. (Brassicaceae)]. Although the preferred hosts for settling and oviposition were the same as those that supported maximum fitness (adult longevity, fecundity, and nymph survivorship), these hosts differed between B and Q. When given a choice, B preferred to settle and oviposit on cabbage over poinsettia and cotton, whereas Q preferred to settle and oviposit on poinsettia and cotton over cabbage. In a no-choice experiment, adult longevity, fecundity, and nymphal survival for B were greater on cabbage than on poinsettia and cotton, but the opposite was true for Q.

Twenty nine novel N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N′-phenyl ureas were designed and synthesized, and their structures were confirmed by proton nuclear magnetic resonance (1H NMR), infra red spectroscopy (IR) and high-resolution mass spectroscopy (HRMS). Compounds V-9, V-11, V-12, V-15, V-19, V-21, V-22 and V-24 exhibit excellent activity against Culex pipiens pallens. Compounds V-12 and V-22 present good insecticidal activity against Plutella xylostella L. Their median lethal concentrations (LC50) are 164.15 and 89.69 mg·L−1, respectively. Compound V-11 also has potential wide spectrum of fungicide activity. Its median effective concentrations (EC50) detected from 3.82 µg·mL−1 against Physalospora piricola to 31.60 µg·mL−1 against Cercospora arachidicola. Compounds V-15 and V-24 show outstanding induction activities as same as positive controls TDL and ningnanmycin, furthermore V-24 has the highest induction activity of 41.85%±4.43%. To elucidate the structure activity relationship in these compounds, a 3D-QSAR model has been built. The established model showed a reliable predicting ability with q2 values of 0.643 and r2 values of 0.982.

Bemisia tabaci shifted unexpectedly in China from a predominance of B biotype to Q biotype during 2005–2008. This observation stimulated an interest in investigating whether environmental factors, including host, temperature and relative humidity (RH) could possibly explain the observed shift in biotypes distribution. Results indicated that all three parameters examined influenced biotype survivability. The percentage of B biotype, when reared together on pepper plants with the Q biotype, decreased significantly from 66.7% in the founder population, to 13.6% and 3.7% in the first and second generations, respectively. When the B (founder at 66.7%) and Q (founder at 33.3%) biotypes were reared together on eggplant alone, or on pepper-plus-eggplant combination, the population size of the B biotype either remained constant, or increased somewhat in the first and second generations. On eggplant, the effects of RH and temperature on the competitiveness between the Q and B biotypes (3 pairs of Q and 6 pairs of B) were not significant.