Plant defense negates pathogen manipulation of vector behavior

1. Although many vector‐borne plant pathogens can alter vector behaviour to the pathogen\u27s benefit, how plants might counter such manipulation is unknown. 2. 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. 3. 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. 4. 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. 5. The presence of the JA pathway in many plant species suggests that similar interactions may be widespread in nature

Difference in Feeding Behaviors of Two Invasive Whiteflies on Host Plants with Different Suitability: Implication for Competitive Displacement

In China, Bemisia tabaci Q (commonly known as biotype Q) has rapidly displaced B (commonly known as biotype B) in the past 6 years. The mechanisms underlying such phenomenon have been studied extensively in recent years; however, we have not come to a definitive conclusion yet. In the present study, the differences in host suitability between B and Q whitefly adults to five host plants (cabbage, cotton, cucumber, poinsettia, and tomato) were evaluated based on their respective feeding behaviors using a direct-current electrical penetration graph (DC-EPG) system. Pair-wise comparisons of B. tabaci B and Q feeding on each of the five host plants clearly indicate that Q feeds better than B on tomato, cotton and poinsettia, while B feeds better than Q on cabbage and cucumber. The EPG parameters related to both phloem and non-phloem phases confirm that cabbage and cucumber are best suited to B, while tomato, cotton, and poinsettia are best suited to Q. Our present results support the contention that host suitability and adult feeding behavior contribute to the competitive displacement of biotype B by biotype Q. The discrepancy between field (previous studies) and laboratory results (this study), however, suggests that 1) whitefly displacement is apparently contributed by multiple factors; and 2) factor(s) other than the host plant suitability may play a vital role in dictating the whitefly biotypes in the field

Variation in both host defense and prior herbivory can alter plant-vector-virus interactions

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. 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 MED. The apparent attraction of MED to neophytadiene may prove useful in pest detection and management

Transcriptomic and proteomic responses of sweetpotato whitefly, Bemisia tabaci, to thiamethoxam

BACKGROUND: The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most widely distributed agricultural pests. Although it has developed resistance to many registered insecticides including the neonicotinoid insecticide thiamethoxam, the mechanisms that regulate the resistance are poorly understood. To understand the molecular basis of thiamethoxam resistance, omics analyses were carried out to examine differences between resistant and susceptible B. tabaci at both transcriptional and translational levels. RESULTS: A total of 1,338 mRNAs and 52 proteins were differentially expressed between resistant and susceptible B. tabaci. Among them, 11 transcripts had concurrent transcription and translation profiles. KEGG analysis mapped 318 and 35 differentially expressed genes and proteins, respectively, to 160 and 59 pathways (p CONCLUSIONS: This study demonstrates the applicability of high-throughput omics tools for identifying molecular candidates related to thiamethoxam resistance in an agricultural important insect pest. In addition, transcriptomic and proteomic analyses provide a solid foundation for future functional investigations into the complex molecular mechanisms governing the neonicotinoid resistance in whiteflies

Rapid spread of tomato yellow leaf curl virus in China is aided differentially by two invasive whiteflies

BACKGROUND: Tomato yellow leaf curl virus (TYLCV) was introduced into China in 2006, approximately 10 years after the introduction of an invasive whitefly, Bemisia tabaci (Genn.) B biotype. Even so the distribution and prevalence of TYLCV remained limited, and the economic damage was minimal. Following the introduction of Q biotype into China in 2003, the prevalence and spread of TYLCV started to accelerate. This has lead to the hypothesis that the two biotypes might not be equally competent vectors of TYLCV. METHODOLOGY/PRINCIPAL FINDINGS: The infection frequency of TYLCV in the field-collected B. tabaci populations was investigated, the acquisition and transmission capability of TYLCV by B and Q biotypes were compared under the laboratory conditions. Analysis of B. tabaci populations from 55 field sites revealed the existence of 12 B and 43 Q biotypes across 18 provinces in China. The acquisition and transmission experiments showed that both B and Q biotypes can acquire and transmit the virus, however, Q biotype demonstrated superior acquisition and transmission capability than its B counterparts. Specifically, Q biotype acquired significantly more viral DNA than the B biotype, and reached the maximum viral load in a substantially shorter period of time. Although TYLCV was shown to be transmitted horizontally by both biotypes, Q biotype exhibited significantly higher viral transmission frequency than B biotype. Vertical transmission result, on the other hand, indicated that TYLCV DNA can be detected in eggs and nymphs, but not in pupae and adults of the first generation progeny. CONCLUSIONS/SIGNIFICANCE: These combined results suggested that the epidemiology of TYLCV was aided differentially by the two invasive whiteflies (B and Q biotypes) through horizontal but not vertical transmission of the virus. This is consistent with the concomitant eruption of TYLCV in tomato fields following the recent rapid invasion of Q biotype whitefly in China

Factors Affecting Population Dynamics of Maternally Transmitted Endosymbionts in Bemisia tabaci

While every individual of Bemisia tabaci (Hemiptera: Aleyrodidae) harbors the primary symbiont (P-symbiont) Portiera, the infection frequencies of the six secondary symbionts (S-symbionts) including Hamiltonella, Arsenophonus, Cardinium, Wolbachia, Rickettsia and Fritschea vary greatly among different populations. To characterize the factors influencing the infection dynamics of the six S-symbionts in B. tabaci, gene-specific PCR were conducted to screen for the presence of the P-symbiont Portiera and the six S-symbionts in 61 (17 B and 44 Q biotypes) field populations collected from different plant species and locations in China. All individuals of the 61 populations hosted the P-symbiont Portiera, but none of them harbored Arsenophonus and Fritschea. The presence and infection rates of Hamiltonella, Cardinium, Rickettsia, Wolbachia and their co-infections Rickettsia + Hamiltonella (RH), Rickettsia + Cardinium (RC), Hamiltonella + Cardinium (HC) and Rickettsia + Hamiltonella + Cardinium (RHC) varied significantly among the 61 field populations; and the observed variations can be explained by biotypes, sexes, host plants and geographical locations of these field populations. Taken together, at least three factors including biotype, host plant and geographical location affect the infection dynamics of S-symbionts in B. tabaci

Multiple Forms of Vector Manipulation by a Plant-Infecting Virus: \u3cem\u3eBemisia tabaci\u3c/em\u3e and \u3cem\u3eTomato Yellow Leaf Curl Virus \u3c/em\u3e

For many insect-vectored plant viruses, the relationship between feeding behavior and vector competence may prove integral to an understanding of the epidemiology of the resulting plant disease. While plant-infecting viruses are well known to change host plant physiology in a way that makes them more attractive to vectors, viral manipulation of the vectors themselves has only recently been reported. Previous research suggested that the rapid spread of Tomato yellow leaf curl virus (TYLCV) throughout China has been facilitated by its primary vector, the whitefly Bemisia tabaci. We conducted two experiments testing the impact of TYLCV infection of the host plant (tomato) and vector (B. tabaci biotypes B and Q) on whitefly feeding behavior. Whiteflies of biotypes B and Q both appeared to find TYLCV-infected plants more attractive, probing them more quickly and having a greater number of feeding bouts; this did not, however, alter the total time spent feeding. Viruliferous whiteflies fed more readily than uninfected whiteflies and spent more time salivating into sieve tube elements. Because vector salivation is essential for viral transmission, this virally mediated alteration of behavior should provide TYLCV a direct fitness benefit. This is the first report of such manipulation by a nonpropagative virus that belongs to an exclusively plant-infecting family of viruses (Geminiviridae). In the context of previous research showing that feeding on TYLCV-infected plants harms biotype B but helps biotype Q, the fact that both biotypes were equally affected by TYLCV also suggests that the virus may alter the biotype B-biotype Q competitive interaction in favor of biotype Q

Plant-mediated changes in the feeding behavior of an invasive whitefly

The invasive whitefly Bemisia tabaci (Gennadius) is a worldwide pest of agricultural crops that feeds on a wide variety of host plants. Although host plant preference is known to vary among B. tabaci biotypes, far less is known about the potential for intraspecific divergence caused by long-term isolation on a single species of host plant. We tested the hypothesis that multigenerational isolation of B. tabaci B, a biotype that has been well-established in China for nearly two decades, on three different host plants would lead to population-level divergence in feeding behaviors. We used individuals from a cabbage-feeding (Brassica oleracea L.) population of B. tabaci B to create three populations reared exclusively on B. oleracea, cucumber (Cucumis sativus L.), or tomato (Lycopersicon esculentum Mill.) for \u3e80 generations. We then used electrical penetration graph techniques to investigate the feeding behavior of the three B. tabaci populations on each of the three host plants (nine total treatments). Across all three host plants, the cabbage-specific population equaled or exceeded the performance of the cucumber-specific (CuSP) and tomato-specific (ToSP) populations. Strikingly, neither CuSP nor ToSP ever had the best feeding performance on their natal hosts. Our results support the hypothesis that feeding differentiation has occurred, but we found no evidence that these changes increased the feeding performance of either CuSP or ToSP. Although confirming that rapid interpopulation divergence is possible, our findings nonetheless suggest that this differentiation did not yield highly adapted populations that might pose problems for future efforts at pest management. © 2013 Entomological Society of America

Design of An Intelligent Split-type Electricity Utilization Measurement and Control Terminal for Local Household Energy Management and Optimization

It is of great significance to implement automatic demand response (ADR) in the energy Internet based on accurate measurement and control of electricity utilization devices using intelligent terminals. Current intelligent terminals lack flexibility and possess weak data collection and processing capabilities. On this basis, this paper developed an intelligent split-type electricity utilization measurement and control terminal for local household energy management and optimization. This intelligent terminal has capabilities of digital signal processing and infrared-based precision control, which is composed of two separate parts: the device body and the infrared controller. Among them, the device body includes DSP chip, electrical sampling circuit, ADC chip, WiFi module, ZigBee module, etc. The infrared controller contains single-chip microcomputer, ZigBee module, infrared encoding and transmit-receiving module, and lithium-ion battery. The device body is able to provide commands to the infrared controller according to the collected electricity utilization information, environmental information and comprehensive demand response requirements, thereby accurately adjusting the operating status of the loads, namely the electrical household appliances. Due to the split-type and rechargeable design, this intelligent terminal is able to adapt to a complex home environment, laying the hardware foundation for effective home energy management and optimization and facilitating household loads participating in demand response, especially automatic demand response

Data from: Plant defense negates pathogen manipulation of vector behavior

1. Although many vector-borne plant pathogens can alter vector behavior to the pathogen's benefit, how plants might counter such manipulation is unknown. 2. 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 anti-herbivore defenses, affected the ability of TYLCV to (A) manipulate Bemisia behavior; and (B) infect plants. 3. 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. 4. 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. 5. The presence of the JA pathway in many plant species suggests that similar interactions may be widespread in nature