Impact of pre-harvest fungicide application on the storage performance of tomato fruits.

To examine the impact of pre-harvest fungicide applications on the postharvest storage performance of tomato fruits, we measured the lycopene content, hardness, soluble solids content, rotting rate, and weight loss rate of the fruits, as well as conducted a sensory assessment. Protective and systematic fungicides were sprayed on tomatoes 20 days before harvest in order to prevent rotting and weight loss during storage. Our findings showed that, the fungicide-treated tomatoes had a significantly lower rotting rate of 16.00% and a weight loss rate of 3.96%. However the control group experienced 65.33% rotting rate and 6.90% weight loss rate on 12th days of storage. Out of the pre-harvest applications, 'Zineb' a protective fungicide significantly delayed the loss of hardness and soluble solids accumulation in tomato fruits during storage, but it had no significant effect on lycopene content. On the other hand, when comparing to the examined treatment, the systemic fungicides did not have any significant effect on the postharvest storage performance of tomato fruits. Sensory evaluation results indicated that systemic fungicides improved the aroma of the fruits, while protective fungicides had a greater impact on the appearance and juiciness of the fruits. This study offers a potential novel solution for preserving fruits and vegetables which have been frequently infected by phytopathogens during storage, and consequently mitigate/reduce postharvest losses.

Specific volatiles of tea plants determine the host preference behavior of Empoasca onukii.

Empoasca onukii is a major pest that attacks tea plants. To seek effective and sustainable methods to control the pest, it is necessary to assess its host preference among different species of tea and understand the critical factors behind this behavior. In this study, the behavioral preference of E. onukii for volatile organic compounds (VOCs) of three potted tea species was evaluated. The VOCs released by the three tea species were analyzed using gas chromatography-mass spectrometry, and the major components were used to test the pest's preference. Transcriptome analysis was used to infer the key genes that affect the biosyntheses of the VOCs. The results showed that the tendency of E. onukii toward the VOCs of the three tea species was the strongest in green tea, followed by white tea, and the weakest in red tea. This behavioral preference was significantly and positively correlated with the relative levels of hexanol, linalool, and geraniol in tea volatiles. Relative hexanol was significantly and positively correlated with the expression of genes TEA009423 (LOX2.1), TEA009596 (LOX1.5), TEA008699 (HPL), TEA018669 (CYPADH), and TEA015686 (ADHIII). Relative linalool was significantly and positively correlated with the expression of genes TEA001435 (CAD) and Camellia_sinensis_newGene_22126 (TPS). Relative geraniol was significantly and positively correlated with the expression of genes TEA001435 (CAD), TEA002658 (CYP76B6), TEA025455 (CYP76T24), and Camellia_sinensis_newGene_22126 (TPS). The above findings suggested that three volatiles (hexanol, linalool, and geraniol) determined the behavioral preference of E. onukii toward tea plants, and their biosynthesis was mainly affected by nine genes (TEA009423, TEA009596, TEA008699, TEA018669, TEA015686, TEA001435, TEA002658, TEA025455, and Camellia_sinensis_newGene_22126).

Phytopathogens Increase the Preference of Insect Vectors to Volatiles Emitted by Healthy Host Plants.

Phytopathogen infections not only affect the physiology of host plants but also the preference of insect vectors; these modifications may increase the spread of infection. For this, we determined the effects of "Candidatus Liberibacter asiaticus" (CLas) infection on the preference of an insect vector (Diaphorina citri) for its uninfected or CLas-infected host (Citrus sinensis) and found that the infected vector preferred uninfected citrus, while the uninfected vector preferred infected citrus. We identified two compounds, (Z)-3 hexenyl and methyl salicylate, that were differentially abundant in the volatiles emitted by infected and uninfected citrus and two odorant-binding protein (OBP) genes differentially expressed between infected and uninfected vectors. The results of receptor-ligand binding assays indicated that CLas upregulated OBP A10 expression in the infected vector to target (Z)-3 hexenyl acetate emitted by uninfected citrus and induced citrus to emit more methyl salicylate for binding to OBP2 in the uninfected vector. Our results might be useful for the effective control of CLas infections.

Whitefly-induced tomato volatiles enhance the virulence of Lecanicillium lecanii.

Entomopathogenic fungi (EPF) are a group of microorganisms that have potential for replacing synthetic chemical pesticides. However, EPF virulence is often insufficient, and therefore adoption of EPF biopesticides has been relatively limited. Previous studies have shown that herbivore-induced plant volatiles (HIPVs) promoted the virulence of Lecanicillium lecanii, and that extracellular proteases and chitinases are important virulence factors of entomopathogenic fungi. We therefore put forward the hypothesis that HIPVs promote L. lecanii virulence by inducing extracellular protease or/and chitinase activity. Lecanicillium lecanii was treated with tomato HIPVs induced by various numbers/densities of Bemisia tabaci, the effect of HIPVs on L. lecanii virulence and activities of virulence-related enzymes (extracellular proteases and chitinases) was analyzed. Changes in enzyme activities were confirmed by measuring the variations in Pr1 and Chit II genes expression of virulence-related enzymes under the influence of HIPVs. Finally, the correlation between virulence and virulence-related enzymes or genes was analyzed to explore the mechanism of promoting HIPVs in L. lecanii virulence enhancement. The results showed that volatiles produced by the tomato plants induced by 50 B. tabaci adults (50-HIPVs) significantly enhanced the virulence of L. lecanii. When exposed to both 50-HIPVs and L. lecanii, the mortality rate of B. tabaci reached 79.0% within 7 days compared to 28.87% in the control group. Additionally, 50-HIPVs significantly promoted the activity of chitinase and the relative expression of Chit II genes, which consequently increased by 62.74% and 48.55%, respectively. However, each group of HIPVs had no promoting effect on extracellular protease and Pr1 gene expression. Correlation analysis results showed that the virulence of L. lecanii is significantly correlated with the activity of chitinase and relative expression of Chit II genes. Thus, HIPVs induced virulence of L. lecanii by increasing chitinase activity. This study demonstrates important methods to enhance the virulence of L. lecanii. Moreover, from the perspective of chemical ecology, the findings provide theoretical support for field application of EPF, and also reveal the impact of HIPVs on EPF from a biochemical perspective.

Diamondback Moth Larvae Trigger Host Plant Volatiles that Lure Its Adult Females for Oviposition.

The diamondback moth (DBM) is a destructive pest of crucifer crops. In this study, DBM larvae shown to herbivore induced plant volatiles (HIPVs) that were attractive to adult females exposed in a Y-tube olfactometer. Our results showed that olfactory responses of adult females to HIPVs induced by third instar larvae feeding on Barbarea vulgaris were significantly higher (20.40 ± 1.78; mean moths (%) ± SD) than those induced by first instar larvae (14.80 ± 1.86; mean moths (%) ± SD). Meanwhile, a significant concentration of Sulphur-containing isothiocyanate, 3-methylsulfinylpropyl isothiocyanate, and 4-methylsulfinyl-3-butenyl isothiocyanate were detected in HIPVs released by third instar larvae compared to those released by first instar larvae while feeding on B. vulgaris. When the DBM females were exposed to synthetic chemicals, singly and in blend form, a similar response was observed as to natural HIPVs. Our study demonstrated that the relationship between isothiocyanates acting as plant defense compounds, host plant cues emission and regulation of the DBM adult female behavior due to key volatile triggered by the DBM larvae feeding on B. vulgaris.

Citronellal perception and transmission by Anopheles gambiae s.s. (Diptera: Culicidae) females.

Anopheles gambiae s.s. is a key vector of Plasmodium parasites. Repellents, which may be a promising alternative to pesticides used to control malaria mosquitoes. Although citronellal is a known mosquito repellent, its repellency characteristics are largely unknown. Determining the specific odorant-binding proteins (OBPs) and odorant receptors (ORs) that detect and transfer the citronellal molecule in A. gambiae s.s. will help to define the mode of action of this compound. In this research, we assessed the repellent activity of citronellal in A. gambiae s.s. using a Y-tube olfactory meter, screened candidate citronellal-binding OBPs and ORs using reverse molecular docking, clarified the binding properties of predicted proteins for citronellal using fluorescence competition binding assay. Results showed that citronellal had a dosage effect on repelling A. gambiae s.s.. The 50% repellent rate was determined to be 4.02 nmol. Results of simulated molecular docking showed that the only proteins that bound tightly with citronellal were AgamOBP4 and AgamORC7. Fluorescence competitive binding assays confirmed the simulations. This research determined that citronellal was captured by AgamOBP4 and transmitted to AgamORC7 in A. gambiae s.s.. Our study will be beneficial in the further understanding the repellent mechanism of citronellal against A. gambiae s.s..

Immunocompetence of Gynaikothrips uzeli (Thysanoptera: Phlaeothripidae) populations from different latitudes against Beauveria bassiana (Hypocreales: Cordycipitaceae).

Gynaikothrips uzeli gall thrips are protected from insecticide exposure by their leaf gall habitat. A biocontrol strategy based on entomopathogenic fungi is an alternative approach for the control of G. uzeli. Higher temperatures can promote the reproduction and spread of pests; however, the impact of higher temperatures on biological control is unclear. We studied the immunocompetence of thrips from different latitudes and determined the effect of degree days on thrips immunity. We examined the potential impact of temperature on the biocontrol provided by entomopathogenic fungi. Beauveria bassiana pathogenicity against thrips increased with decreasing latitude, suggesting that immunity of thrips increased as latitude increased. The phenoloxidase activity of G. uzeli increased with increasing latitude but there was no significant change in hemocyte concentration. This indicated that the humoral immunity of thrips was significantly associated with degree days, and this was confirmed by transcriptome data. Transcriptome and RT-PCR results showed that the expression of key genes in eight toll pathways increased with increasing latitude. The relative expression of key genes in the Toll pathway of thrips and the activity of phenoloxidase decreased with increasing degree days that are characteristic of lower latitudes. These changes led to a decrease in humoral immunity. The immunity of G. uzeli against entomopathogenic fungi increased as degree days characteristic of lower latitudes decreased. Increased temperatures associated with lower latitude may therefore increase biocontrol efficacy. This study clarified immune level changes and molecular mechanisms of thrips under different degree days.

Ethylene and Benzaldehyde Emitted from Postharvest Tomatoes Inhibit Botrytis cinerea via Binding to G-Protein Coupled Receptors and Transmitting with cAMP-Signal Pathway of the Fungus.

Tomato storage conditions are difficult largely due to Botrytis cinerea infection which causes gray mold disease. However, the effects of the volatile organic compounds (VOCs) emitted by postharvest tomatoes on this fungus remain unclear. We analyzed the effects of tomato-emitted VOCs on B. cinerea pathogenicity, germination, and hyphal growth with bioassay, predicted the causative active compounds by principle component analysis, identified G-protein-coupled receptors (GPCRs) which captured chemical signals in the B. cinerea genome by stimulating molecular docking, tested the binding affinities of these receptors for the active compounds by fluorescence binding competition assay, and identified an associated signaling pathway by RNA interfere. The VOCs emitted by postharvest tomatoes inhibited B. cinerea; ethylene and benzaldehyde were the active compounds causing this effect. One of the identified GPCRs in B. cinerea, BcGPR3, bound tightly to both active compounds. Two genes associated with the cAMP signaling pathway (BcRcn1 and BcCnA) were downregulated in wild-type B. cinerea exposed to the active compounds, as well as in the ΔBcgpr3 B. cinerea mutant. Exposure to postharvest tomato VOCs reduces B. cinerea pathogenicity due to ethylene and benzaldehyde volatiles. The BcGPR3 protein is inactivated by the active compounds, and thus fails to transmit signals to the cAMP pathway, thereby inhibiting B. cinerea.

Endophytic entomopathogenic fungi enhance the growth of Phaseolus vulgaris L. (Fabaceae) and negatively affect the development and reproduction of Tetranychus urticae Koch (Acari: Tetranychidae).

Entomopathogenic fungi (EPF) have primarily been applied as an inundative approach to manage pests. However, in recent decade multifunctional role of EPF have been documented which provide multiple benefits to host plants when colonized as an endophyte. In this study five fungal isolates from the genus Beauveria (three), Isaria (one) and Lecanicillium (one) were evaluated for their ability to colonize common bean, Phaseolus vulgaris and to assess their effects in planta on plant growth promotion and possible negative effects on the two-spotted spider mites, Tetranychus urticae. All the tested isolates in this study were able to endophytically colonize root, stem and even leaves of inoculated plants examined at 7 and 14 days post inoculation, indicating the systemic colonization of EPF. Colonized plants showed increased plant heights, fresh shoot and root weights compared to plants without inoculation. Survivorship of T. urticae significantly differed among the treatments with higher survival probability in control plants. Significant reduction in larval development, adult longevity and female fecundity of spider mites were observed when fed on treated plants compared to control plants. The negative effects were found to be carried over the second generation fed on fresh plants. Overall, our results show (i) the positive effects of fungal endophytes on plant growth, (ii) reduction in population growth rate and (iii) negative effects of endophytes on growth and reproduction of spider mites in successive generations. The study presents reports on the endophytic management of plant-feeding mites and highlights the possibility of utilizing entomopathogenic fungal endophytes in the integrated pest management program.

Effects of flower thrips (Thysanoptera: Thripidae) on nutritional quality of banana (Zingiberales: Musaceae) buds.

The abundance of banana flower thrips (Thrips hawaiiensis Morgan) in a banana (Musa acuminata Colla "Williams" cultivar) plantation was investigated using yellow sticky traps (29.70 cm × 21.00 cm) in 2015. Banana flower thrips occurred throughout the year with monthly variation, and the maximum occurrence was observed in October and November during the bud burst (73.80 ± 6.32 adults/trap) and young fruit (70.06 ± 5.69 adults/trap) periods. The damage rates were as follows: interior flowers >3rd-layer flowers > 2nd-layer flowers > 1st-layer flowers > young fruits. This result indicates that thrips migrated to lower bracts, young fruits, and other flower buds as bracts gradually opened. Results also showed that the reducing sugar, vitamin C, protein and ash contents in thrips-damaged flowers were all significantly lower than those in undamaged flowers, while there was no significant difference between damaged and undamaged young banana fruit. Our results indicated that the abundances of banana flower thrips were closely associated with the growing stage of banana. Thrips mainly infested flower buds and caused a reduction in nutrients for the host plant, especially the reducing sugar and vitamin C contents, which reduced the nutritional quality of banana fruits and the quality of flower bud by-products of banana.

Imidacloprid Pesticide Regulates Gynaikothrips uzeli (Thysanoptera: Phlaeothripidae) Host Choice Behavior and Immunity Against Lecanicillium lecanii (Hypocreales: Clavicipitaceae).

We attempted to develop an efficient management strategy against gall thrips (Gynaikothrips uzeli Zimmermann (Thysanoptera: Phlaeothripidae)) via the combined application of a systemic insecticide (imidacloprid) and an entomopathogenic fungus (Lecanicillium lecanii Zimmerman (Hypocreales: Clavicipitaceae)). The attraction of G. uzeli to Ficus microcarpa volatiles after imidacloprid treatment was weaker than for untreated plants, which could be due to modulation of volatile metabolite profiles by imidacloprid. The toxicity of L. lecanii against nymph and adult thrips was much higher for those that fed on plants treated with a 50% lethal concentration (LC50) of imidacloprid than for the controls. Phenoloxidase (PO) activity was significantly inhibited in treated G. uzeli, while hemocyte abundances were not different in treated and healthy individuals. Thus, imidacloprid impacted the PO-related humoral immunity of G. uzeli, but not their cellular immunity. Overall, F. microcarpa treated with imidacloprid at LC50 concentrations exhibited volatile profiles that decreased the attraction of G. uzeli and also indirectly increased the pathogenicity of L. lecanni by inhibiting the humoral immunity of gall thrips. The results reported here suggest that combined application of imidacloprid and L. lecanii could be used as a new integrated control strategy against gall thrips.

Temperature-dependent development of Asian citrus psyllid on various hosts, and mortality by two strains of Isaria.

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a devastating pest of Citrus spp. The aim of present study was to investigate the development and mortality of ACP on citrus (Citrus sinensis) (healthy and Huánglóngbìng- (HLB) diseased) and jasmine (Murraya paniculata) plants at various temperatures. Two new Isaria strains were collected from citrus orchards of Fuzhou (China), and HLB-diseased plants were verified by running PCR for 16S gene of Candidatus Liberibacter asiaticus (CLas). Development observations were recorded for egg, nymph and adult stages on all plants and three different temperatures (20, 25 and 30 °C) whereas mortality observations were recorded for the nymph (fifth instar) and adults on all plants at 25 °C. Field collected Isaria strains were belonged to previously reported Chinese strains under Maximum Parsimony (MP) and Maximum Likelihood methods, as well as, CLas isolates were belonged to previously reported Chinese isolates under MP and Neighbor-Joining methods. The fastest development and mortality was observed on HLB-diseased plants whereas longest time was taken by development and mortality completion on jasmine plants at all temperatures. The fastest developmental times of egg, nymph (first to fourth and fifth instar) and adult stages were ranged from 3.02 to 3.72 d, to 7.63-9.3 d, 5.35-5.65 d and 24.46-28.47 d on HLB-diseased plants at 30-20 °C, respectively. On the other hand, I. javanica caused the fastest mortality of nymphs and adults (32.21 ± 4.47% and 19.33 ± 4.51%) on HLB-diseased plants with the concentration of 1 × 108 conidia.mL-1 after 3 d and 7 d, respectively. It is concluded that there is a need for extensive molecular work to understand the extra-development and mortality of ACP on diseased plants, because, CLas bacterium can be supportive to uptake more sap from plant phloem.

Phylogenetic relationship and genetic diversity of citrus psyllid populations from China and Pakistan and their associated Candidatus bacterium.

Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a severely devastating pest of Rutaceae plants, mainly citrus, across the globe, and causal agent of Huanglongbing (HLB) disease. To find out the genetic relationship and diversity among the populations of ACP and associated Candidatus Liberibacter asiaticus (CLas) from two countries (China and Pakistan), sequence data of three different genes, cytochrome oxidase subunit I (COI), Cu-transporting protein (ATOX1) and 16S rRNA, were used to characterize all populations. In the present study, MEGA-7 and statistical parsimony software (TCS-1.2) were used to depict the phylogenetic relationship among all populations under both genes, whereas diversity was calculated by DnaSP v5. All analyses were done for country wise and overall relationship among all populations. For ACP populations, both genes presented a significant strong intermingled relationship among all populations and put all population into a single haplotype (Dcit-2), which proved similarity between Chinese and Pakistani populations. Moreover, for CLas strains, 16S gene also presented strong relationship for all sampled populations. All three genes of ACP and CLas populations elucidated more than 95% resemblance to each other. On the other hand, a significant genetic variation was observed by three genes for overall populations, although, country wise variation was non-significant between all collected populations. ATOX1 gene presented higher diversity through Fu's Fs test (π = 0.01081, p < 0.003) whereas COI gene gave less diversity under Fu's Fs and Tajima's D test (π = 0.00512, p < 0.000 and 0.05, respectively). Similarly, nucleotide mismatch distribution also had shown enough genetic variation among all ACP populations, under both genes. Our sequence data for both genes proved the invasion of the Chinese ACP population (Dcit-2) into Pakistan, through all phylogenetic relationship, which proved a similar genetic makeup among all ACP populations from both countries. Therefore, these results can be helpful to utilize any novel designed control measure equally for both countries.

Susceptibilities of Candidatus Liberibacter asiaticus-infected and noninfected Diaphorina citri to entomopathogenic fungi and their detoxification enzyme activities under different temperatures.

Some entomopathogenic fungi species, Isaria fumosorosea, and Hirsutella citriformis were found to be efficient against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). However, the susceptibility to these fungi increases when the psyllid infected with Candidatus Liberibacter asiaticus (Las), which is transmitted by D. citri and causes citrus greening disease. In this study, we examined the Las-infected and Las-uninfected D. citri susceptibility to entomopathogenic fungi at different temperature regimes (5-40°C). When D. citri adults exposed to cold temperature (5°C), they showed less susceptibility to entomopathogenic fungi as compared with control (27°C). Irrespective of infection with Las, a significantly positive correlation was observed between temperature and percentage mortality caused by different isolates of I. fumosorosea, 3A Ifr, 5F Ifr, PS Ifr, and H. citriformis isolates, HC3D and 2H. In contrast, a significantly negative correlation was found between temperature and percentage mortality for 3A Ifr for both Las-infected and Las-uninfected psyllids. Detoxification enzymes, Glutathione S-transferase levels in D. citri showed a negative correlation, whereas cytochrome P450 and general esterase levels were not correlated with changes in temperature. These findings revealed that detoxification enzymes and general esterase levels are not correlated with altered susceptibility to entomopathogenic fungi at the different temperature regimes. Conclusively, temperature fluctuations tested appear to be a significant factor impacting the management strategies of D. citri using entomopathogenic fungi.

Effects of different temperature regimes on survival of Diaphorina citri and its endosymbiotic bacterial communities.

The Asian citrus psyllid, Diaphorina citri, is a major pest of citrus and vector of citrus greening (huanglongbing) in Asian. In our field-collected psyllid samples, we discovered that Fuzhou (China) and Faisalabad (Pakistan), populations harbored an obligate primary endosymbiont Candidatus Carsonella (gen. nov.) with a single species, Candidatus Carsonella ruddii (sp. nov.) and a secondary endosymbiont, Wolbachia surface proteins (WSP) which are intracellular endosymbionts residing in the bacteriomes. Responses of these symbionts to different temperatures were examined and their host survival assessed. Diagnostic PCR assays showed that the endosymbionts infection rates were not significantly reduced in both D. citri populations after 24 h exposure to cold or heat treatments. Although quantitative PCR assays showed significant reduction of WSP relative densities at 40°C for 24 h, a substantial decrease occurred as the exposure duration increased beyond 3 days. Under the same temperature regimes, Ca. C. ruddii density was initially less affected during the first exposure day, but rapidly reduced at 3-5 days compared to WSP. However, the mortality of the psyllids increased rapidly as exposure time to heat treatment increased. The responses of the two symbionts to unfavorable temperature regimes highlight the complex host-symbionts interactions between D. citri and its associated endosymbionts.

The Herbivore-Induced Plant Volatiles Methyl Salicylate and Menthol Positively affect Growth and Pathogenicity of Entomopathogenic Fungi.

Some herbivore-induced-plant volatiles (HIPVs) compounds are vital for the functioning of an ecosystem, by triggering multi-trophic interactions for natural enemies, plants and herbivores. However, the effect of these chemicals, which play a crucial role in regulating the multi-trophic interactions between plant-herbivore-entomopathogenic fungi, is still unknown. To fill this scientific gap, we therefore investigated how these chemicals influence the entomopathogenic fungi growth and efficacy. In this study, Lipaphis erysimi induced Arabidopsis thaliana HIPVs were collected using headspace system and detected with GC-MS, and then analyzed the effects of these HIPVs chemicals on Lecanicillium lecanii strain V3450. We found that the HIPVs menthol and methyl salicylate at 1 and 10 nmol·ml-1 improved many performance aspects of the fungus, such as germination, sporulation, appressorial formation as well as its pathogenicity and virulence. These findings are not only important for understanding the multi-trophic interactions in an ecosystem, but also would contribute for developing new and easier procedures for conidial mass production as well as improve the pathogenicity and virulence of entomopathogenic fungi in biological pest management strategies.

Volatiles from Plants Induced by Multiple Aphid Attacks Promote Conidial Performance of Lecanicillium lecanii.

Herbivore-induced plant volatiles (HIPVs) are clues that help predatory insects search for food. The hypothesis that entomopathogenic fungi, which protect plants, benefit from the release of HIPVs was tested. The plant Arabidopsis thaliana was used as the source of HIPVs. The insect herbivore Lipaphis erysimi (Kaltenbach) was used as the inducer, and the fungal pathogen of the aphid Lecanicillium lecanii was exposed to HIPVs to test our hypothesis. When exposed to aphid-induced A. thaliana volatiles, the mortality of aphids pre-treated with a conidial suspension of L. lecanii, the conidial germination and the appressorial formation were significantly increased compared with the control. The decan-3-ol and 4-methylpentyl isothiocyanate that were detected in the headspace seemed to have positive and negative affection, respectively. Moreover, HIPVs generated from groups of eight aphids per plant promoted significantly increased conidial germination and appressorial formation compared with HIPVs from groups of one, two and four aphids per plant. Our results demonstrated that the pathogenicity of the entomopathogenic fungus L. lecanii was enhanced when exposed to HIPVs and that the HIPVs were affected by the number of insect herbivores that induced them.

Diaphorina citri Induces Huanglongbing-Infected Citrus Plant Volatiles to Repel and Reduce the Performance of Propylaea japonica.

Transmission of plant pathogens through insect vectors is a complex biological process involving interactions between the host plants, insects, and pathogens. Simultaneous impact of the insect damage and pathogenic bacteria in infected host plants induce volatiles that modify not only the behavior of its insect vector but also of their natural enemies, such as parasitoid wasps. Therefore, it is essential to understand how insects such as the predator ladybird beetle responds to volatiles emitted from a host plant and how the disease transmission alters the interactions between predators, vector, pathogens, and plants. In this study, we investigated the response of Propylaea japonica to volatiles from citrus plants damaged by Diaphorina citri and Candidatus Liberibacter asiaticus through olfactometer bioassays. Synthetic chemical blends were also used to determine the active compounds in the plant volatile. The results showed that volatiles emitted by healthy plants attracted more P. japonica than other treatments, due to the presence of high quantities of D-limonene and beta-ocimene, and the lack of methyl salicylate. When using synthetic chemicals in the olfactory tests, we found that D-limonene attracted P. japonica while methyl salicylate repelled the predator. However, beta-ocimene attracted the insects at lower concentrations but repelled them at higher concentrations. These results indicate that P. japonica could not efficiently search for its host by using volatile cues emitted from psyllids- and Las bacteria-infected citrus plants.

An adenosine A1 agonist 2-chloro-N6 cyclopentyladenosine inhibits the angiotensin II-induced cardiomyocyte hypertrophy through the calcineurin pathway.

OBJECTIVES: The aim of this investigation was to study the underlying mechanism of an adenosine A1 receptor agonist 2-chloro-N6 cyclopentyladenosine (CCPA) inhibiting cardiomyocyte hypertrophy induced by angiotensin II (AngII). METHODS: Neonatal rat cardiomyocytes were treated with AngII to generate a cardiomyocyte hypertrophy model. Cardiomyocyte cultures were randomized into 5 groups: control; AngII; AngII + cyclosporin A (CsA); AngII + CCPA, and AngII + CCPA + DPCPX. Cardiomyocyte viability was measured by MTT assay. Protein synthesis was assessed by the application of (3)H leucine ((3)H-Leu) incorporation into protein. The mRNA expressions of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), ß-myosin heavy chain (ß-MHC) and calcineurin Aß (CnAß) were measured by real-time quantitative PCR. The protein level of CnAß was dissected by Western blotting. RESULTS: AngII administration at lower concentrations increased the cardiomyocytes viabilities gradually. Surface area, mRNA expressions of ANP, BNP and ß-MHC, and (3)H-Leu incorporation of AngII-induced cardiomyocytes were increased in a dose-dependent manner. As a calcineurin-specific inhibitor, CsA inhibited (3)H-Leu incorporation, surface area, mRNA expressions of ANP, BNP, ß-MHC, CnAß and protein expression of CnAß of AngII-induced cardiomyocytes. CCPA also suppressed the mRNA and protein expressions of CnAß and exerted antihypertrophic effects to a greater degree than CsA. The inhibition of CCPA on cardiomyocyte hypertrophy was counteracted by the A1 receptor antagonist DPCPX. CONCLUSION: The A1 receptor agonist CCPA could significantly inhibit AngII-induced cardiomyocyte hypertrophy via the calcineurin signaling pathway.

[Level of SDF-1/CXCR4 in children with acute leukemia and its significance].

The objective of this study was to detect the level of plasma stromal cell-derived factor-1 (SDF-1) and the expression of CXCR4 (SDF-1 receptor in bone marrow cells) in children with Acute Leukemia (AL) and to investigate the relationship between the expression of CXCR4 and extramedullary infiltration. 48 children with acute leukemia and 20 with non-hematologic malignancies were selected into the AL group and the control group respectively. The peripheral plasma and bone marrow cells were collected. The level of SDF-1 in peripheral plasma was detected by ELISA and the expression of CXCR4 in bone marrow cells was determined by flow cytometry. The results showed that the levels of SDF-1 in peripheral plasma and the expression of CXCR4 in bone marrow cells of AL group was significantly higher than that of control group, among which the level of SDF-1 of the acute lymphoblastic leukemia (ALL) group was also higher than that of the acute myeloid leukemia (AML) group, the expression level of CXCR4 in the bone marrow cells of the extramedullary infiltration (EI) group was higher than that of the non-extramedullary Infiltration (NI) group, and all the differences between the both groups were significant. It is concluded that SDF-1 and CXCR4 express a high level in children with AL, which closely relates with the type of leukemia and the migration and infiltration of leukemia cells in bone marrow.