Regulation of hemolymph trehalose titers by insulin signaling in the legume pod borer, <i>Maruca vitrata</i> (Lepidoptera: Crambidae)

Al Baki, Md. Abdullah,Jung, Jin Kyo,Kim, Yonggyun Elsevier 2018 Peptides Vol.106 No.-

<P><B>Abstract</B></P> <P>A disaccharide, trehalose, is a main hemolymph sugar of the legume pod borer, <I>Maruca vitrata</I> larvae, but its titers fluctuated with feeding activity. During diurnal feeding in the photophase, hemolymph trehalose remained at a relatively low level (69 mM) and increased (98 mM) during scotophase. Starvation significantly increased the hemolymph trehalose level, in which the elevation of trehalose titers was dependent on the non-feeding period. The down-regulation of the trehalose level during the active feeding period seemed to result from mediation of the insulin/IGF signal (IIS). Injection of a porcine insulin suppressed the trehalose level in a dose-dependent manner. Genes associated with IIS of <I>M. vitrata</I> were predicted from its larval transcriptome, and their expression was confirmed in different developmental stages and tissues. All seven IIS genes selected were expressed in all developmental stages and different tissues. Silencing of four IIS genes (insulin receptor, Forkhead box O, a serine-threonine protein kinase, target of rapamycin) by RNA interference significantly modulated the hemolymph trehalose level. Starvation treatment changed expression of two trehalose metabolism-associated genes (trehalose phosphate synthase (TPS) and trehalase (TRE)) as well as the IIS genes. Silencing of <I>TPS</I> or <I>TRE</I> expression significantly down- or up-regulated the hemolymph trehalose level, respectively. In addition, silencing of IIS genes altered both <I>TPS</I> and <I>TRE</I> expression, indicating a functional link between IIS and trehalose metabolism. These results suggest that nutrients obtained from feeding activate IIS of <I>M. vitrata</I>, which then down-regulates the hemolymph trehalose level by altering trehalose metabolism.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An ILP/IGF signal (IIS) pathway is predicted from <I>Maruca vitrata</I>. </LI> <LI> Feeding rhythm coincides with IIS expression to maintain plasma trehalose level. </LI> <LI> RNA interference of IIS gene expression resulted in significant increase of plasma trehaloe level. </LI> </UL> </P>

Age grading and gene flow of overwintered Bactrocera scutellata populations

Abdullah Al Baki,금은선,김현정,송영림,김용균,권기명,박영진 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.4

The striped fruit fly, Bactrocera scutellata, belongs to family Tephritidae. It infests pumpkin flowers. It is known to overwinter as adult stage with possible diapause development. However, its overwintering biology remains unclear. The objective of this study was to determine its overwintering regions in Korea. First, overwintering adults were collected and used to measure supercooling point (SCP) to understand its low limit temperature for survival. Male adults exhibited mean SCP at −7.2 °C. During winter, Jeju and some southern mainland regions with temperatures above −7 °C might be overwintering regions for B. scutellata. Based on such putative overwintering zone, male adult monitoring was performed from January to June in five different localities. Jeju and southern mainland regions (Yangsan, Uiryeong) had overwintered populations whereas mid- and northern regions (Andong, Guri) did not have such overwintered population. Amounts of pterin amounts in heads of overwintered populations were most increased in May and June, suggesting adult development and relatively long lifespan. Males collected in late spring possessed melanized testis filled with apparently matured spermatozoa. Genetic distances between overwintered populations of Jeju and mainland regions were measured using random amplification of polymorphic DNA. They showed separate clustering between Jeju and mainland populations. These results indicate that B. scutellata overwinters in both Jeju and southern mainland regions of Korea.

Validation of insulin signaling pathway using CRISPR-Cas9 in Maruca vitrata

Md. Abdullah Al Baki,Yonggyun Kim 한국응용곤충학회 2019 한국응용곤충학회 학술대회논문집 Vol.2019 No.04

Insulin/IGF signaling (IIS) regulates multiple physiological processes such as larval growth, reproduction, and life span in many organisms including legume pod borer, Maruca vitrata (Lepidoptera: Crambidae). RNA interference of IIS components, insulin receptor (InR) and Forkhead Box O (FOXO), impaired larval growth and female reproduction. To further validate the physiological roles of InR and FOXO, we generated knock-out (KO) mutants using CRISPR/Cas9-mediated genome-editing technology. Both KO mutants exhibited delayed larval growth and reduced pupal and adult body sizes. In conclusion, these results demonstrated the critical role of insulin signaling (IIS) pathway to control M. vitrata growth and development.

Application of gene expression of insulin signaling pathway to insect growth modeling

Md. Abdullah Al Baki,Yonggyun Kim 한국응용곤충학회 2017 한국응용곤충학회 학술대회논문집 Vol.2017 No.10

Insect growth depends on temperature and nutrient. Intake nutrients activate insulin signaling pathway, which mediatesthe nutrient signal to coordinate growth in entire body. A subtropical species, Maruca vitrata (Lepidoptera: Crambidae),gives serious damages on various Fabaceae crops. This study predicted seven components (InR, IRS, PI3K, PTEN, Akt,mTOR, FOXO) of the insulin signal and showed that some of the insulin gene expression levels are highly correlatedwith developmental rates. These correlations may be applied to amend a temperature-dependent growth modeling of M.vitrata.

Insulin/IGF signaling regulates female reproduction by stimulating stem cells in germarium

Md. Abdullah Al Baki,Yonggyun Kim 한국응용곤충학회 2018 한국응용곤충학회 학술대회논문집 Vol.2018 No.04

Insulin/IGF signaling (IIS) regulates different physiological processes such as metabolism, trehalose level, growth, and reproduction. Four IIS components are identified from the bean pod borer, Maruca vitrata (Lepidoptera: Crambidae). RNA interference (RNAi) of insulin receptor (InR), Forkhead Box O (FOXO), Target of Rapamycin (TOR) or Akt led to ovary dysfunction. Especially, the RNAi treatment significantly reduced the stem cell division in the germarium. However, an addition of a porcine insulin stimulated the cell division. Immature diets significantly influenced on the ovarian stem cell development.

Oocyte and sperm development of the striped fruit fly, Zeugodacus scutellata

Md. Abdullah Al Baki,Yonggyun Kim 한국응용곤충학회 2019 한국응용곤충학회 학술대회논문집 Vol.2019 No.10

Discrimination of different generations of Zeugodacus scutellata using age grading technique and their local genetic variation

김용균,Md. Abdullah Al Baki,권기면,김동순,박계청,안정준 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.3

The striped fruit fly, Zeugodacus scutellata, exhibits generation overlap due to its relatively long lifespan. This study clarified the fly generations by age-grading technique and traced migration of local populations using genetic markers. Male adults were monitored using Cue-lure in two different places (Andong and Guri) of mainland Korea during the entire host cultivating period. They showed two occurrence peaks (from late July to early August and from mid-August to mid-October). A developmental model of Z. scutellata using rate summation method predicted four generations during this period. Pterin amounts in fly heads increased with adult age and indicated at least 3 cycles of age variation during the occurrence period with an additional adult generation after the third cycle. The additional peak was supported by field monitoring using protein diet supplemented with terpinyl acetate, which showed an additional occurrence peak during October. These seasonal populations were monitored through their migration by gene flow analysis using randomly amplified polymorphic DNA (RAPD) markers. In each locality, three seasonal populations at July, August, and September were discrete. Although local populations were genetically discrete at July, they were not separate at late seasons except for Jeju populations. These results indicate the usefulness of the head pterin quantification in age-grading of adult populations and suggest that Z. scutellata occurs at least four generations a year. In addition, gene flow analysis using RAPD suggests frequent movements among local populations along with season progression.

Calcium/calmodulin-dependent protein kinase II of the oriental fruit fly, Bactrocera dorsalis, and its association with rapid cold hardiness

안정준,최경선,Shaw-Yhi Huang,Md. Abdullah Al Baki,아메드 샤비르,김용균 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.4

The oriental fruit fly, Bactrocera dorsalis, is a serious insect pest with diverse host range. Furthermore, its invasive and polyphagous behaviors allow this species to expand its habitats. Recent climate change and increase of international trade/transportation facilitate the species expansion from subtropical to temperate regions. Low temperature during winter appears to be the major factor limiting its expansion to temperate zones in the northern hemisphere. This study reports its remarkable ability in rapid cold-hardening (RCH) along with deep supercooling capacity. A brief exposure to 9 °C significantly enhanced cold tolerance of its larvae, pupae, and adults. RCH took 1–2 h for pupae and adults, although it took 24 h for larvae. Supercooling capacity of pupae was also enhanced by RCH treatment from −13.4 °C to −16.6 °C. To trace genetic factors associated with RCH, calcium/calmodulin-dependent protein kinase II (Bd-CaMKII) was identified from B. dorsalis and their expression in response to RCH treatment was analyzed. Bd-CaMKII possesses three conserved domains of kinase, calmodulin, and oligomerization. Bd-CaMKII is highly homologous to CaMKII of D. melanogaster and other tephritid flies. Expression levels of Bd-CaMKII in the larvae treated with RCH were significantly increased by approximately 5.5 folds compared to those in control larvae. In addition, expression levels of HSP70 and HSP90 were also increased in response to RCH treatment. These results along with previous studies suggest that cold-hardening of B. dorsalis is functionally associated with its supercooling capacity with increased production of cryoprotectants and HSP through regulatory activity of Bd-CaMKII.

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김용균,압둘라알바키,권기면,Kim, Yonggyun,Al Baki, Md. Abdullah,Kwon, Gimyeon 한국응용곤충학회 2020 한국응용곤충학회지 Vol.59 No.1

The striped fruit fly, Zeugodacus scutellata, is endemic in Korea, but it has been regarded as one of the serious quarantine pests throughout the world. Sterile insect release technique (SIT) has been used to eradicate quarantine fruit flies. This study developed a technique to generate sterile males and applied SIT to control Z. scutellata. First of all, the reproductive systems of Z. scutellata adults were examined with fluorescent microscope. Polytrophic ovaries comprises of around 100 follicles with developing oocytes. Each follicle contains an oocyte with several nurse cells and are surrounded with follicular epithelium. Oocyte development began at 10 days after adult emergence (DAE) and formed chorionated oocytes after 20 DAE. On the other hand, male testes were well developed just after adult emergence. The vas deferens was filled with motile sperms. To generate sterile males, different doses (0~1,000 Gy) doses of electron beam were irradiated to 3~5 days old pupae of Z. scutellata. When male pupae were irradiated with electron beam at 200 Gy, they developed and mated with females without any significant difference compared to untreated males. Although the untreated females mated with the 200 Gy-irradiated males laid eggs, no eggs did not hatch. The 200 Gy-irradiated males were then applied to untreated male and female flies in a density ratio of 1:9 (untreated males : treated males). The laid eggs suffered significant infertility. These results suggest that electron beam-irradiated pupae at 200 Gy resulted in male sterility and the resulting males would be applied to SIT.

Monitoring the Oriental Fruit Fly (Bactrocera dorsalis), the Melon Fly (B. cucurbitae), and B. tau Fruit Fly Using Wax Formation Lures

김용균,몰라이맘,압둘라 알바키,안정준,Kim, Yonggyun,Imam, Mollah,Al Baki, Md. Abdullah,Ahn, Jeong Joon Korean Society of Applied Entomology 2018 한국응용곤충학회지 Vol.57 No.1

Out of 60 quarantine insect pests in Korea, 42 species are classified into tephritid fruit flies. Most of these fruit flies are attracted to two natural products, methyl eugenol (ME) or raspberry ketone. Paraffin wax has been devised to formulate these lures. The formulated lures were applied to field test in Taiwan to attract quarantine fruit flies. Wax-ME formulation was installed in Delta trap and could attract 60-80 males of B. dorsalis per day during late August, while a wax formulation of Cue-lure (a methylated compound of raspberry ketone) attracted both B. cucurbitae and B. tau. These wax formulations can be applied to monitor these three quarantine species in Korea.