The putative‐farnesoic acid O‐methyl transferase (FAMeT) gene of Ceratitis capitata: characterization and pre‐imaginal life expression

Farnesoic acid O‐methyl transferase (FAMeT) is the enzyme involved in the penultimate step of insect juvenile hormone (JH) biosynthesis and is thus a key regulator in insect development and reproduction. We report the characterization of the putative‐FAMeT in the medfly or Mediterranean fruit fly, Ceratitis capitata. This gene was identified by suppressive subtractive hybridization and completely sequenced by the screening of a medfly cDNA library. The obtained sequence was analyzed for conserved protein domain identification and its expression profile was evaluated by quantitative Real‐Time PCR in medfly pre‐imaginal life. The tissue expression of the isolated gene was verified by in situ hybridization on third instar larvae sections. The characterization of the isolated gene pointed out several typical features of methyl transferase genes. The pre‐imaginal putative‐FAMeT expression levels were consistent with JH titer change in Diptera. As recognized in some crustaceans, this gene seems to be widely expressed in the medfly as well. Ceratitis capitata is one of the most relevant agricultural pests against which insecticides and the sterile insect technique (SIT) are extensively used in spite of the well‐known limitations of these approaches. Although results are not conclusive for the physiological role of the isolated gene, they suggest the characterization of a new gene in the Mediterranean fruit fly potentially involved in JH biosynthesis and may, therefore, have implications for pest control. © 2010 Wiley Periodicals, Inc.     

Effects of diet and host access on fecundity and lifespan in two fruit fly species with different life‐history patterns

The reproductive ability of female tephritids can be limited and prevented by denying access to host plants and restricting the dietary precursors of vitellogenesis. The mechanisms underlying the delayed egg production in each case are initiated by different physiological processes that are anticipated to have dissimilar effects on lifespan and reproductive ability later in life. The egg‐laying abilities of laboratory‐reared females of the Mediterranean fruit fly (Ceratitis capitata Wiedmann) and melon fly (Bactrocera cucurbitae Coquillett) from Hawaii are delayed or suppressed by limiting access to host fruits and dietary protein. In each case, this is expected to prevent the loss of lifespan associated with reproduction until protein or hosts are introduced. Two trends are observed in each species: first, access to protein at eclosion leads to a greater probability of survival and a higher reproductive ability than if it is delayed and, second, delayed host access reduces lifetime reproductive ability without improving life expectancy. When host access and protein availability are delayed, the rate of reproductive senescence is reduced in the medfly, whereas the rate of reproductive senescence is generally increased in the melon fly. Overall, delaying reproduction lowers the fitness of females by constraining their fecundity for the remainder of the lifespan without extending the lifespan. © 2013 The Royal Entomological Society     

An egg‐laying device to estimate the induction of sterility in Ceratitis capitata (Diptera: Tephritidae) sterile insect technique programmes

Area‐wide environmentally friendly pest control methods such as the sterile insect technique (SIT) are being developed and improved to contribute in managing agricultural, environmental and public health problems. A key aspect to evaluate performance of sterile males is to directly measure sterility induction in the field. Sterility induction has been estimated for tephritid fruit flies by recovering egg from host fruit in the field, the method is, however, impractical, and past efforts to develop artificial egg‐laying devices have not prospered. Here, we evaluated response of wild gravid Ceratitis capitata (Medfly) females to long‐distance fruit‐based chemical attractants, visual and tactile stimuli to develop an artificial egg‐laying device. The device combining the most attractive features was further tested under two deployment schemes. Finally, devices and deployment tactics were used to compare fertility levels between feral Medfly females under conventional management and under SIT. Agar spheres wrapped in plastic film, baited with pressed peach juice and visually enhanced with yellow discs received more egg than other combinations of attractive features. Such devices also received more eggs when deployed on fruitless trees and when placed on the orchard perimeter. The egg hatch in an orchard under conventional management was estimated at 86%, whilst egg hatch in an area under SIT was reduced to 31%. The egg‐laying devices are therefore useful to measure sterility induction and can be further improved by refining long‐distance attraction and deployment schemes.     

Mate choice by wild and mass‐reared females of the Mediterranean fruit fly

The sterile insect technique (SIT) is used to control Mediterranean fruit fly, Ceratitis capitata (Wiedemann), but its effectiveness is limited by low sexual competitiveness of mass‐reared males. This study investigated whether wild and mass‐reared [from a temperature sensitive lethal (tsl) genetic sexing strain] females display similar mate preferences and thus exert similar selective forces on the evolution of male courtship behaviour. Wild females preferred wild males over tsl males, whereas tsl females mated indiscriminately. The probability that mounting resulted in copulation was related to the duration of pre‐mount courtship for wild females, and wild males performed longer courtships than tsl males. Copulation occurred independently of courtship duration in tsl females. Counter to the aim of the SIT, female choice by tsl females appears to promote the evolution of male behaviour disfavoured by wild females.     

Expression of juvenile hormone acid O‐methyltransferase and juvenile hormone synthesis in Blattella germanica

Juvenile hormone (JH), a sesquiterpenoid synthetized by the insect corpora allata (CA), plays critical roles in metamorphosis and reproduction. Penultimate or last step of JH synthesis is catalyzed by juvenile hormone acid O‐methyltransferase (JHAMT). Here we report the cloning and expression analysis of the JHAMT orthologue in the cockroach, Blattella germanica (L.) (BgJHAMT). BgJHAMT is mainly expressed in CA, with only expression traces in ovary. Three different isoforms, differing in the 3′‐UTR sequence, were identified. Isoform A shows between 35 and 65 times higher expression than B and C in CA from penultimate nymphal instar and adult females. RNAi‐triggered knock down of BgJHAMT produces a dramatic reduction of JH synthesis, concomitant with a decrease of fat body vitellogenin expression and basal follicle length. BgJHAMT mRNA levels in CA of females along the gonadotrophic cycle parallel, with a slight advancement, JH synthesis profile. BgJHAMT mRNA levels were reduced in starved females and in females in which we reduced nutritional signaling by knocking down insulin receptor and target of rapamycin (TOR). Results show that conditions that modify JH synthesis in adult B. germanica females show parallel changes of BgJHAMT mRNA levels and that the JH‐specific branch of the JH synthesis pathway is regulated in the same way as the mevalonate branch. Furthermore, we demonstrate that nutrition and its signaling through the insulin receptor and TOR pathways are essential for activating BgJHAMT expression, which suggests that this enzyme can be a checkpoint for the regulation of JH production in relation to nutritional status.     

The biosynthesis of Juvenile Hormone, its degradation and titres in females of the true armyworm: a comparison of migratory and non-migratory populations

In a previous study [ McNeil et al. (1996) Archives of Insect Biochemistry and Physiology, 32, 575–584], patterns of sexual maturation and Juvenile Hormone (JH) biosynthesis were compared in virgin females from migratory (North American) and non‐migratory (Azorean) populations of the true armyworm moth, Pseudaletia unipuncta Haworth (Lepidoptera: Noctuidae). Sexual maturation occurred at a significantly earlier age after emergence in the non‐migrant population, and the rates of biosynthesis of JH in vitro suggested that lower titres of JH may be required to initiate the onset of calling behaviour (pheromone emission) and ovarian development in Azorean females. To examine the physiological differences in the reproductive biology of migratory and non‐migratory populations in greater detail, the haemolymph titres of JH and JH esterase activity were compared in virgin females as a function of age. In addition, the effects of mating on JH biosynthesis in vitro, JH titres, JH esterase activity and egg production were measured in the two populations. As expected, JH titres rose more rapidly after emergence in Azorean females than in their North American counterparts but, contrary to our prediction, the maximum levels were also higher in the non‐migrant population. Activity of JH esterase was much higher in Azorean females on the day of emergence. However, by the second day both populations had similar activity levels (about 17 nmol JH/min/ml) and exhibited a similar age‐related decline in subsequent days. Mating did not affect the rate of JH biosynthesis in vitro but resulted in a significant increase in the titres of JH in the haemolymph of both populations. The maximum titre (a five‐fold increase) occurred within 24 h of mating in Azorean females. In North American individuals the increase was greater (seven‐fold) but did not occur until 48 h after mating. No difference in the activity of JH esterase was observed between mated and virgin North American females. By contrast, while there was an age‐related decline in the activity of JH esterase in mated Azorean females, as seen in both North American groups, activity levels in virgin females remained constant with age. In all females, mating resulted in a significant increase in egg production within 24 h. The Azores is a volcanic archipelago, so these non‐migratory populations were probably founded by immigrants originating from migratory continental populations. It is clear from our results that the change from a life history that includes migration to a non‐migratory one involved more than just a temporal shift in the timing of the production of JH. Furthermore, the interpopulation differences in titres of JH and mating‐induced changes reported here cannot be fully explained by the observed differences in the patterns of activity of JH esterase and JH biosynthesis in vitro.     

Attract‐and‐kill systems efficiency against Ceratitis capitata (Diptera: Tephritidae) and effects on non‐target insects in peach orchards

For control of the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae), the attract‐and‐kill or attracticide technique is an alternative to the spraying of traditional organophosphate pesticides. In this study, the effectiveness of Ceranock and AAL&K attract‐and‐kill bait stations was assessed for control of C. capitata in Tunisian peach (Prunus persica) orchards. Our results showed that, in orchards with early‐ripening varieties, the numbers of C. capitata males and fruit damage were significantly lower in plots treated with Ceranock and AAL&K bait stations than in plots treated with conventional organophosphate and pyrethroid insecticides. In addition, the abundances of non‐target insects in the Chrysopidae, Coccinellidae and Miridae were significantly greater in plots treated with the bait stations than in plots treated with the conventional pesticides; that is, the use of attract‐and‐kill bait stations had fewer negative effects than the application of conventional pesticides on the biological diversity in Tunisian peach orchards. Overall, the results indicate that Ceranock and AAL&K attract‐and‐kill bait stations are useful alternatives for the control of C. capitata in Tunisian peach orchards planted with early‐ripening varieties.     

Cloning and characterization of Methoprene-tolerant(Met)and Kruppel homolog 1(Kr-h1)genes in the wheat blossom midge,Sitodiplosis mosellana

Juvenile hormone(JH),a growth regulator,inhibits ecdysteroid-induced meta-morphosis and controls insect development and diapause.Methoprene-tolerant(Met)and Krippel homolog I(Kr-h1)are two proteins involved in JH action.To gain some insight into their function in development of Sitodiplosis mosellana,an insect pest undergoing obligatory larval diapause at the mature 3rd instar stage,we cloned full-length complemen-tary DNAs of Met and Kr-h1 from this specics.SmMet encoded a putative protein,which contained three domains typical of the bHLH-PAS family and eight conserved amino acid residues important for JH binding.SmKr-h1 encoded a protein showing high sequence homology to its counterparts in other specics,and contained all eight highly conserved Zn-finger motifs for DNA-binding.Expression patterns of SmMet and SmKr hl were de-velopmentally regulated and JH III responsive as well.Their mRNA abundance increased as larvae entered carly 3rd instar,pre-diapause and maintenance stages,and peaked during post-diapause quiescence,a pattern correlated with JH titers in this species.Different from reduced expression of SmMer,SmKr-h1 mRNA increased at mid-to-late period of post-diapause development.Topical application of JH II on diapausing larvac also induced the two genes in a dose-dependent manner.Expression of SmuMer and SmKr-h1 clearly declined in the pre-pupal phase,and was significantly higher in female adults than male adults.These results suggest that JH-responsive SmMet and SmKr-h1 might play key roles in diapause induction and maintenance as well as in post-diapause quiescence and adult reproduction,whereas metamorphosis from larvae to pupac might be correlated with their reduced expression.     

Cloning and structural characterization of juvenile hormone diol kinase in Spodoptera litura

Juvenile hormone (JH) is one of the key insect hormones that regulate metamorphosis. Juvenile hormone diol kinase (JHDK) is an enzyme involved in JH metabolism and catalyzes JH diol to form a polar end product, JH diol phosphate that has no JH activity. In this study, a JHDK complementary DNA (cDNA) was cloned from Spodoptera litura and the structure and expression of the gene was characterized. The cDNA was 714 base pairs in length and encoded a protein of 183 amino acids with a molecular mass of 21 kDa and an isoelectric point of 4.55. Based on the structure, three putative calcium binding motifs and guanosine triphosphate‐binding motifs were predicted in the protein. Modeling of the 3‐D structure showed that the protein consisted of eight α‐helixes linked with loops, with no β‐sheets. The gene was expressed in the epidermis, fat body and midgut of fifth and sixth instar larvae. The expression level in the epidermis was lower than in the fat body and midgut. The gene was expressed at higher levels at the early stages than in the later stages of fifth and sixth instar midgut and fat body. The results suggest that this gene may be involved in the regulation of the JH titer in larvae of S. litura.     

Vitellogenin and egg production in the moth,Heliothis virescens

The characteristics of vitellogenin (Vg) and the relationship between Vg production and egg production in the tobacco budworm, Heliothis virescens, were studied. The relationship between Vg production and juvenile hormone (JH) and the impact of mating on Vg and egg production were also investigated. Vg appears in the hemolymph of H. virescens about 6 h after moth eclosion. Vg may be separated into two apoproteins (ApoVg-I and ApoVg-II) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weights were calculated to be 156,065 ± 800 for ApoVg-I and 39,887 ± 323 for ApoVg-II. SDS-PAGE analysis revealed that the female hemolymph Vg polypeptides appear to be identical to those from eggs but are absent in male hemolymph. Vg concentration was significantly higher in mated females than in virgin females of the same age at 48 h after emergence. Rates of egg production increased as Vg production increased; rates of egg production in mated females were significantly higher than those of virgin females at 48, 72, 96, and 120 h postemergence. Vg production is dependent on JH, because hemolymph from decapitated females lacked Vg while that of decapitated females treated with synthetic JH had Vg at levels comparable to similarly aged, normal H. virescens females. Hemolymph JH titers in mated females were significantly higher compared with those in virgin females at all sampling periods. The high JH level in mated females may explain the high Vg and egg production in mated H. virescens. Arch. Insect Biochem. Physiol. 34:287–300, 1997. © 1997 Wiley-Liss, Inc.     

A real‐time PCR toolbox for accurate identification of invasive fruit fly species

Significant plant pests such as fruit flies that travel with fresh produce between countries as eggs or larvae pose a great economic threat to the agriculture and fruit industry worldwide. Time‐limited and expensive quarantine decisions require accurate identification of such pests. Immature stages are often impossible to identify, making them a serious concern for biosecurity agencies. Use of COI barcoding PCR, often the only molecular identification resource, is time‐consuming. We assess the suitability of the COI barcoding region for real‐time PCR assays to identify four pest fruit fly species (Family: Tephritidae), in a diagnostic framework. These species, namely Mediterranean fruit fly (Ceratitis capitata), Queensland fruit fly (Bactrocera tryoni), African invader fly (Bactrocera invadens) and Island fly (Dirioxa pornia) each provide a different set of genetic species delimitation problems. We discuss the benefits and limitations of using a single‐gene TaqMan^? real‐time approach for such species. Our results indicate that COI‐based TaqMan^? real‐time PCR assays, in particular for genetically distinct species, provide an accurate, sensitive and rapid diagnostic tool.     

Juvenile hormone–stimulated synthesis of acyl‐glycerols and vitamin E in female accessory sexual glands of the fire bug,Pyrrhocoris apterus L.

Secretory cells of the female accessory sexual glands (AG) of P. apterus grow and produce yellow oily exocrine secretion in response to stimulation by endogenous juvenile hormone (JH) or exogenous treatments by JH analogues. The secretion determines the property of future egg shells by coating the chorion surface of the oocytes that are passing individually through the common uterus during oviposition. Diapausing females with a physiologically inhibited endocrine system or females with artificially removed hormonal sources show inactive ovaries and empty AG without the secretory products. Ovary‐ectomised females with the intact neuroendocrine system develop hypertrophic AG loaded with the oily secretion. This shows that there is no direct dependence between formation of the oily secretion in AG and ovarian growth. Chemical analysis of the secretory products revealed the presence of acetylated glycerols, with the most abundant stearoyl‐diacetyl‐glycerol, stearoyl‐acetyl‐propionyl‐glycerol, and the corresponding derivatives of arachidonic acid. In addition to this, the JH‐activated secretory cells of AG also produced γ‐ and δ‐tocopherols. The possible antioxidant or antimutagenic action of these vitamin E compounds in insect reproduction has been emphasized. © 2009 Wiley Periodicals, Inc.     

Spatio‐temporal distribution of Ceratitis capitata population in a heterogeneous landscape in Central Italy

The spatio‐temporal dynamics of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was investigated to evaluate the effect of the landscape elements and host plants on pest distribution, in an agricultural landscape of 500 ha located in Central Italy. Two farms (farm 1 and farm 2) are located in the experimental area, composing mixed fruit orchards and surrounded by hedgerows, small woodlots, private gardens and cereal fields. Ceratitis capitata population fluctuation was monitored, from 2006 to 2008, using traps baited with trimedlure. Geostatistical methods such as Inverse distance squared weighted were used to obtain distributional maps of adults, mainly males. Results showed that the adult Mediterranean fruit flies were primarily distributed inside farm 1, with the maximum density found in the months of September and October. Away from the principal host plants, particularly in cereal fields, the number of trapped individuals was always low or zero. In both farms, flies were caught sequentially in traps located on host plants (i.e. peach, apple, pear, oriental persimmon and prickly pear) at varying times of maturation, especially when fruits remained on the trees. Distributional maps provided evidence that allowed to identify habitats in which the fly developed early in the season (mixed peach orchards) and afterwards during the periodic flights.     

Identification of Differentially Expressed Genes in the Pheromone Glands of Mated and Virgin Bombyx mori by Digital Gene Expression Profiling

Background

Mating decreases female receptivity and terminates sex pheromone production in moths. Although significant progress has been made in elucidating the mating-regulated inactivation of pheromone biosynthesis-activating neuropeptide (PBAN) secretion, little is known about the mating induced gene expression profiles in pheromone glands (PGs). In this study, the associated genes involved in Bombyx mori mating were identified through digital gene expression (DGE) profiling and subsequent RNA interference (RNAi) to elucidate the molecular mechanisms underlying the mating-regulated gene expression in PGs.

Results

Eight DGE libraries were constructed from the PGs of mated and virgin females: 1 h mating (M1)/virgin (V1) PGs, 3 h mating (M3)/virgin (V3) PGs, 24 h mating (M24)/virgin (V24) PGs and 48 h mating (M48)/virgin (V48) PGs (M48 and V48). These libraries were used to investigate the gene expression profiles affected by mating. DGE profiling revealed a series of genes showing differential expression in each set of mated and virgin female samples, including immune-associated genes, sex pheromone synthesis-associated genes, juvenile hormone (JH) signal-associated genes, etc. Most interestingly, JH signal was found to be activated by mating. Application of the JH mimics, methoprene to the newly-emerged virgin females leaded to the significant reduction of sex pheromone production. RNAi-mediated knockdown of putative JH receptor gene, Methoprene tolerant 1 (Met1), in female pupa resulted in a significant decrease in sex pheromone production in mature females, suggesting the importance of JH in sex pheromone synthesis.

Conclusion

A series of differentially expressed genes in PGs in response to mating was identified. This study improves our understanding of the role of JH signaling on the mating-elicited termination of sex pheromone production.     

Capture of mass‐reared vs. wild‐like males of Ceratitis capitata (Dipt., Tephritidae) in trimedlure‐baited traps

The sterile insect technique (SIT) is widely used to suppress or eradicate infestations of the Mediterranean fruit fly, Ceratitis capitata (Wied.), an insect whose broad polyphagy poses a serious threat to fruit and vegetable crops. The SIT involves the production, sterilization and release of sterile insects to obtain sterile male by wild female matings, thus yielding infertile eggs. Mass‐rearing over many generations is known to produce dramatic changes in the behaviour and life history of C. capitata. This study investigated the possibility that mass‐rearing also alters male response to trimedlure, a sex‐specific attractant widely used in detection and monitoring programmes. We compared captures of released males from a mass‐reared strain and a recently established colony of wild flies in trimedlure‐baited Jackson traps at three spatial scales – open field, large field enclosures (75 m²) and small field cages (7 m²) – in two separate years. In the first year, males were used independently of flight ability, while in the second year only males with demonstrated flight capability were used. Trap capture was scored 2 days after release for the open field and the large field enclosures but either 1 h or 1 day after release in the small field cages. The findings were consistent across these different experiments: wild‐like males were captured in significantly greater numbers than mass‐reared males in both years of study, except in the trials lasting 1 day in the small field cages where significantly more wild than mass‐reared males were captured in 1 year but not the other. These results are compared with other studies, and their implications for SIT are discussed.     

Do reproductive activities compromise immunological competence as measured by phenoloxidase activity? Field and experimental manipulation in females of two damselfly species

Recent studies of female insects indicate that reproductive activities, such as mating and oviposition, can impair immune ability. Using the two tropical damselfly species Argia anceps Garrison and Hetaerina americana (Fabricius), egg production and phenoloxidase (PO) activity, a key enzyme in insect immunity, are measured in mating, ovipositing and perching females in December and March. Perching females of both species have fewer eggs compared with mating and ovipositing females, which suggests that perching females are not engaged in reproduction. There is seasonal variation in egg number for the three categories in H. americana but not in A. anceps, which can be interpreted in terms of adaptive changes in egg production depending on female–male interactions in the former species but not in the latter species. There is no difference in PO activity among mating, ovipositing or perching females within either species, although measurements in December and March indicate distinct seasonal changes. Juvenile Hormone (JH) is known to reduce the effectiveness of the immune system by favouring the use of resources for reproduction. A possible role for JH is examined in H. americana, using the JH analogue methoprene to manipulate hormone activity, revealing that PO activity is reduced in methoprene‐treated H. americana females. Thus, although the results of the present study are indicative of possible hormone‐driven changes in PO, there is not necessarily a down‐regulation of immune function (as determined by PO activity) during mating or oviposition. The results complement some recent studies countering the idea that reproductive activities reduce the immune ability in insects.     

Acceptability and suitability of six fruit fly species (Diptera: Tephritidae) for Kenyan strains of Psyttalia concolor (Hymenoptera: Braconidae)

Host acceptability and suitability Psyttalia concolor (Szépligeti) is a koinobiont, larval parasitoid of tephritid fruit flies. Individuals of P. concolor were field-collected from coffee in the central highlands of Kenya, and cultured initially on Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann). They were then examined for their ability to oviposit in and develop on five other tephritid species that are pests in Kenya. In addition to the medfly, acceptability for oviposition and suitability for development were tested against the mango fruit fly, Ceratitis cosyra (Walker), the Natal fruit fly, Ceratitis rosa Karsch, Ceratitis fasciventris (Bezzi), Ceratitis anonae Graham and the melon fruit fly, Bactrocera cucurbitae (Coquillett). Ceratitis capitata and C. cosyra were accepted as hosts significantly more often than the other species. Superparasitism was recorded only from C. capitata and C. cosyra. Two days after oviposition, parasitoid eggs in C. fasciventris and B. cucurbitae were encapsulated, whereas those in C. rosa and C. anonae were encapsulated, and often melanized. Ceratitis capitata was the most suitable host for Kenyan populations of Psyttalia concolor in terms of progeny production, and proportion of female progeny.     

Interference between male‐targeted and female‐targeted lures of the Mediterranean fruit fly Ceratitis capitata (Dipt., Tephritidae) in Italy

The efficacy of male‐targeted and female‐targeted baits was compared when lures were presented together or singly in traps for capturing the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). For male‐targeted baits, either trimedlure or ceralure presented singly attracted large numbers of flies, supporting data from many previous reports. The present results are the first published data on the attractiveness of ceralure to a European population of C. capitata. The quaternary female bait consisting of ammonium carbonate, putrescine, trimethylamine and acetic acid was a potent attractant for female flies (and also showed some activity for males). Replacing acetic acid with ammonium acetate in the quaternary female bait did not influence activity. Traps with female‐targeted and male‐targeted baits together always showed a tendency of catching fewer flies than traps with only one type of bait. The decrease was significant in females, regardless of whether ceralure or trimedlure was the male‐targeted bait. In males, the tendency was the same for traps with trimedlure or ceralure alone, catching higher numbers than those with both male and female baits. Our present results suggest that both types of baits mutually decrease the numbers of the non‐target sex in the trap. In conclusion, it is advisable to use both male‐ and female‐targeted baits in separate and distant traps and not jointly in the same trap, lest the efficacy of detection or monitoring trials be compromised.     

Effects of Wolbachia on fitness of the Mediterranean fruit fly (Diptera: Tephritidae)

Wolbachia pipientis is a widespread endosymbiont of insects and other arthropods exerting a wide range of biological effects on their hosts. A growing number of recent studies document the influence of Wolbachia on reproduction and lifespan of insect host species. However, little is known regarding effects of Wolbachia on the demographic traits of different host populations. Moreover, whether different Wolbachia strains exert different effects on fitness components of their hosts remains largely unknown. We studied the effects of (a) the Wolbachia strain wCer2 on fitness components of two laboratory lines of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae) and (b) two different Wolbachia strains (wCer2 and wCer4) on one of the Mediterranean fruit fly lines. Wolbachia infection (wCer2) shortens the egg‐to‐adult developmental duration of both C. capitata lines, although it prolongs embryonic development. In one of the two lines, egg‐to‐adult mortality increased. Wolbachia infection shortens adult lifespan (to a different extent in males and females) and reduces female fecundity. The different Wolbachia strains differentially affect both immature mortality and developmental duration, and adult longevity and female fecundity. Our findings demonstrate both differential response of two C. capitata lines to Wolbachia infection and differential effects of two Wolbachia strains on the same Mediterranean fruit fly line. Practical and theoretical implications of our findings are discussed.     

Transcript profiling of jasmonate‐elicited Taxus cells reveals a β‐phenylalanine‐CoA ligase

Plant cell cultures constitute eco‐friendly biotechnological platforms for the production of plant secondary metabolites with pharmacological activities, as well as a suitable system for extending our knowledge of secondary metabolism. Despite the high added value of taxol and the importance of taxanes as anticancer compounds, several aspects of their biosynthesis remain unknown. In this work, a genomewide expression analysis of jasmonate‐elicited Taxus baccata cell cultures by complementary DNA‐amplified fragment length polymorphism (cDNA‐AFLP) indicated a correlation between an extensive elicitor‐induced genetic reprogramming and increased taxane production in the targeted cultures. Subsequent in silico analysis allowed us to identify 15 genes with a jasmonate‐induced differential expression as putative candidates for genes encoding enzymes involved in five unknown steps of taxane biosynthesis. Among them, the TB768 gene showed a strong homology, including a very similar predicted 3D structure, with other genes previously reported to encode acyl‐CoA ligases, thus suggesting a role in the formation of the taxol lateral chain. Functional analysis confirmed that the TB768 gene encodes an acyl‐CoA ligase that localizes to the cytoplasm and is able to convert β‐phenylalanine, as well as coumaric acid, into their respective derivative CoA esters. β‐phenylalanyl‐CoA is attached to baccatin III in one of the last steps of the taxol biosynthetic pathway. The identification of this gene will contribute to the establishment of sustainable taxol production systems through metabolic engineering or synthetic biology approaches.