The development of Spodoptera frugiperda (Lepidoptera: Noctuidae) on 8 major crops in Japan and its oviposition preference for maize and soybean.

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a polyphagous pest native to the Americas. It first invaded Japan in July 2019, and the most damaged crop in this region to date has been maize. To determine pest control strategies, the range of crops potentially damaged by S. frugiperda in Japan should be identified. In this study, the effects of 8 major crops in Japan-forage maize Zea mays subsp. mays, sugarcane Saccharum officinarum, forage and edible rice Oryza sativa subsp. japonica, soybean Glycine max, eggplant Solanum melongena, green bell pepper Capsicum annuum var. grossum, sweet potato Ipomoea batatas, and taro Colocasia esculenta-on the development of S. frugiperda were analyzed by feeding leaves of domestic cultivars during larval stage. Spodoptera frugiperda developed from hatching to adulthood and laid eggs in all 7 treatments, except for taro. However, among them, only soybean showed comparable developmental suitability to maize. Therefore, its oviposition preference for maize and soybean was examined using further nonchoice and choice tests. In the nonchoice test, the number of egg masses oviposited for 3 days on soybean plants was significantly less than that on test containers, while that on maize was comparable to that on containers. These findings can explain partly why major damage has been limited to maize in Japan.

A multiplex RT-PCR assay combined with co-extraction of DNA and RNA for simultaneous detection of TYLCV and ToCV in whitefly.

Tomato yellow leaf curl virus (TYLCV) and tomato chlorosis virus (ToCV) were transmitted by the sweet potato whitefly Bemisia tabaci (Gennadius) and cause serious yield losses on tomato around the world. To understand the actual situation of co-infection of TYLCV and ToCV of individual whiteflies, we developed multiplex RT-PCR combined with co-extraction of DNA and RNA from a single whitefly. First, a nucleic acid extraction method previously reported was modified and adopted to obtain the RNA-DNA mixture including TYLCV and ToCV in a simple form without manual homogenization. Second, primers were newly designed in actin gene of B. tabaci for the confirmation of extraction and PCR success, and multiplex RT-PCR method was developed using specific primer sets for TYLCV, ToCV and B. tabaci. This method enables the detection of TYLCV and ToCV from a single insect and efficient use of field samples obtained using sticky traps. The method will be useful to monitor infection status of TYLCV and ToCV in the field while reducing labor and cost.

Involvement of the transcription factor E75 in adult cuticular formation in the red flour beetle Tribolium castaneum.

Insect adult metamorphosis generally proceeds with undetectable levels of juvenile hormone (JH). In adult development of the red flour beetle Tribolium castaneum, biosynthesis of adult cuticle followed by its pigmentation and sclerotization occurs, and dark coloration of the cuticle becomes visible in pharate adults. Here, we examined the molecular mechanism of adult cuticular formation in more detail. We noticed that an exogenous JH mimic (JHM) treatment of Day 0 pupae did not inhibit pigmentation or sclerotization, but instead, induced precocious pigmentation of adult cuticle two days in advance. Quantitative RT-PCR analyses revealed that ecdysone-induced protein 75B (E75) is downregulated in JHM-treated pupae. Meanwhile, tyrosine hydroxylase (Th), an enzyme involved in cuticular pigmentation and sclerotization, was precociously induced, whereas a structural cuticular protein CPR27 was downregulated, by exogenous JHM treatment. RNA interference-mediated knockdown of E75 resulted in precocious adult cuticular pigmentation, which resembled the phenotype caused by JHM treatment. Notably, upregulation of Th as well as suppression of CPR27 were observed with E75 knockdown. Meanwhile, JHM treatment suppressed the expression of genes involved in melanin synthesis, such as Yellow-y and Laccase 2, but E75 knockdown did not result in marked reduction in their expression. Taken together, these results provided insights into the regulatory mechanisms of adult cuticular formation; the transcription of genes involved in adult cuticular formation proceeds in a proper timing with undetectable JH, and exogenous JHM treatment disturbs their transcription. For some of these genes such as Th and CPR27, E75 is involved in transcriptional regulation. This study shed light on the molecular mode of action of JHM as insecticides; exogenous JHM treatment disturbed the expression of genes involved in the adult cuticular formation, which resulted in lethality as pharate adults.

Sex-specific expression profiles of ecdysteroid biosynthesis and ecdysone response genes in extreme sexual dimorphism of the mealybug Planococcus kraunhiae (Kuwana).

Insect molting hormone (ecdysteroids) and juvenile hormone regulate molting and metamorphic events in a variety of insect species. Mealybugs undergo sexually dimorphic metamorphosis: males develop into winged adults through non-feeding, pupa-like stages called prepupa and pupa, while females emerge as neotenic wingless adults. We previously demonstrated, in the Japanese mealybug Planococcus kraunhiae (Kuwana), that the juvenile hormone titer is higher in males than in females at the end of the juvenile stage, which suggests that juvenile hormone may regulate male-specific adult morphogenesis. Here, we examined the involvement of ecdysteroids in sexually dimorphic metamorphosis. To estimate ecdysteroid titers, quantitative RT-PCR analyses of four Halloween genes encoding for cytochrome P450 monooxygenases in ecdysteroid biosynthesis, i.e., spook, disembodied, shadow and shade, were performed. Overall, their expression levels peaked before each nymphal molt. Transcript levels of spook, disembodied and shadow, genes that catalyze the steps in ecdysteroid biosynthesis in the prothoracic gland, were higher in males from the middle of the second nymphal instar to adult emergence. In contrast, the expression of shade, which was reported to be involved in the conversion of ecdysone into 20-hydroxyecdysone in peripheral tissues, was similar between males and females. These results suggest that ecdysteroid biosynthesis in the prothoracic gland is more active in males than in females, although the final conversion into 20-hydroxyecdysone occurs at similar levels in both sexes. Moreover, expression profiles of ecdysone response genes, ecdysone receptor and ecdysone-induced protein 75B, were also analyzed. Based on these expression profiles, we propose that the changes in ecdysteroid titer differ between males and females, and that high ecdysteroid titer is essential for directing male adult development.

E93 expression and links to the juvenile hormone in hemipteran mealybugs with insights on female neoteny.

Insect metamorphosis produces reproductive adults and is commonly accompanied with the direct or indirect development of wings. In some winged insects, the imago is altered by life history changes. For instance, in scale insects and mealybugs, reproductive females retain juvenile features and are wingless. The transcription factor E93 triggers metamorphosis and plays in concert with the juvenile hormone pathway to guarantee the successful transition from juvenile to adult. We previously provided evidence of an atypical down-regulation of the juvenile hormone pathway during female development in the Japanese mealybug. Here, we further investigate how E93 is involved in the production of neotenic wingless females, by identifying its isoforms, assessing their expression patterns and evaluating the effect of exogenous juvenile hormone mimic treatment on E93. This study identifies three E93 isoforms on the 5' end, based on Japanese mealybug cDNA and shows that female development occurs with the near absence of E93 transcripts, as opposed to male metamorphosis. Additionally, while male development is typically affected by exogenous juvenile hormone mimic treatments, females seem to remain insensitive to the treatment, and up-regulation of the juvenile hormone signaling is not observed. Furthermore, juvenile hormone mimic treatment on female nymphs did not have an obvious effect on E93 transcription, while treatment on male prepupae resulted in depleted E93 transcripts. In this study, we emphasize the importance in examining atypical cases of metamorphosis as complementary systems to provide a better understanding on the molecular mechanisms underlying insect metamorphosis. For instance, the factors regulating the expression of E93 are largely unclear. Investigating the regulatory mechanism of E93 transcription could provide clues towards identifying the factors that induce or suppress E93 transcription, in turn triggering male adult development or female neoteny.

Vanillylacetone up-regulates anthocyanin accumulation and expression of anthocyanin biosynthetic genes by inducing endogenous abscisic acid in grapevine tissues.

We investigated the effect of vanillylacetone (VA) on anthocyanin accumulation with aim of improving grape berry coloration. Spraying Vitis vinifera cv. Muscat Bailey A berries with VA at veraison increased sugar/acid ratio, an indicator of maturation and total anthocyanin accumulation. To elucidate the molecular mechanism underlying the effect of VA on anthocyanin accumulation, in vitro VA treatment of a grapevine cell culture was carried out. Endogenous abscisic acid (ABA) content was higher in the VA-treated cell cultures than in control at 3h after treatment. Consistent with this, the relative expression levels of anthocyanin-synthesis-related genes, including DFR, LDOX, MybA1 and UFGT, in VA-treated cell cultures were much higher than those in control, and high total anthocyanin accumulation was noted in the VA-treated cell cultures as well. These results suggest that VA up-regulates the expression of genes leading to anthocyanin accumulation by inducing endogenous ABA. In addition, VA increased total anthocyanin content in a dose-dependent manner. Although VA treatment in combination with exogenous ABA did not exhibit any synergistic effect, treatment with VA alone showed an equivalent effect to that with exogenous ABA alone on total anthocyanin accumulation. These findings point to the possibility of using VA for improving grape berry coloration.

Differential Juvenile Hormone Variations in Scale Insect Extreme Sexual Dimorphism.

Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana). We provide, for the first time, detailed gene expression profiles related to JH signaling in scale insects. Prior to adult emergence, the transcript levels of JH acid O-methyltransferase, encoding a rate-limiting enzyme in JH biosynthesis, were higher in males than in females, suggesting that JH levels are higher in males. Furthermore, male quiescent pupal-like stages were associated with higher transcript levels of the JH receptor gene, Methoprene-tolerant and its co-activator taiman, as well as the JH early-response genes, Krüppel homolog 1 and broad. The exposure of male juveniles to an ectopic JH mimic prolonged the expression of Krüppel homolog 1 and broad, and delayed adult emergence by producing a supernumeral pupal stage. We propose that male wing development is first induced by up-regulated JH signaling compared to female expression pattern, but a decrease at the end of the prepupal stage is necessary for adult emergence, as evidenced by the JH mimic treatments. Furthermore, wing development seems linked to JH titers as JHM treatments on the pupal stage led to wing deformation. The female pedomorphic appearance was not reflected by the maintenance of high levels of JH. The results in this study suggest that differential variations in JH signaling may be responsible for sex-specific and radically different modes of metamorphosis.

Emotional distress and its correlates among parents of children with pervasive developmental disorders.

A number of studies have reported that parents of autistic children face higher levels of stress, but few studies examined the stress associated with the home care of children with pervasive developmental disorders (PDD) other than autistic disorder. The aims of the present study were therefore to (i) evaluate the emotional stress level of parents caring for their children with PDD; and (ii) explore the correlates of their emotional stress. Participants were 147 families (147 mothers and 122 fathers) of 158 children with PDD (42 with autistic disorder, 35 with Asperger's disorder and 81 with PDD not otherwise specified). K6 was used to measure the stress level of the parents. Marital relationships and personality were assessed with the Intimate Bond Measure and the NEO Five-Factor Inventory, respectively. The parents also rated the characteristics of their children with PDD through the Pervasive Developmental Disorder-Autism Society Japan Rating Scale (PARS). The mean K6 score of the mothers was significantly higher than that of the women in the general population in Japan. Stepwise multiple regression indicated that the emotional stress of the mothers was correlated with the personality traits of Neuroticism and Agreeableness, perceived Control by the husband, and the children's PARS score. Clinicians can deliver better service by paying appropriate attention to the emotional distress of mothers of children with not only autistic disorder but also other PDD.