scholarly journals Unexpected Mechanism of Symbiont-Induced Reversal of Insect Sex: Feminizing Wolbachia Continuously Acts on the Butterfly Eurema hecabe during Larval Development

2007 ◽  
Vol 73 (13) ◽  
pp. 4332-4341 ◽  
Author(s):  
Satoko Narita ◽  
Daisuke Kageyama ◽  
Masashi Nomura ◽  
Takema Fukatsu

ABSTRACT When the butterfly Eurema hecabe is infected with two different strains (wHecCI2 and wHecFem2) of the bacterial endosymbiont Wolbachia, genetic males are transformed into functional females, resulting in production of all-female broods. In an attempt to understand how and when the Wolbachia endosymbiont feminizes genetically male insects, larval insects were fed an antibiotic-containing diet beginning at different developmental stages until pupation. When the adult insects emerged, strikingly, many of them exhibited sexually intermediate traits in their wings, reproductive organs, and genitalia. The expression of intersexual phenotypes was strong in the insects treated from first instar, moderate in the insects treated from third instar, and weak in the insects treated from fourth instar. The insects treated from early larval instar grew and pupated normally but frequently failed to emerge and died in the pupal case. The dead insects in the pupal case contained lower densities of the feminizing Wolbachia endosymbiont than the successfully emerged insects, although none of them were completely cured of the symbiont infection. These results suggest the following: (i) the antibiotic treatment suppressed the population of feminizing Wolbachia endosymbionts; (ii) the suppression probably resulted in attenuated feminizing activity of the symbiont, leading to expression of intersexual host traits; (iii) many of the insects suffered pupal mortality, possibly due to either intersexual defects or Wolbachia-mediated addiction; and hence (iv) the feminizing Wolbachia endosymbiont continuously acts on the host insects during larval development for expression of female phenotypes under a male genotype. Our finding may prompt reconsideration of the notion that Wolbachia-induced reproductive manipulations are already complete before the early embryonic stage and provide insights into the mechanism underlying the symbiont-induced reversal of insect sex.

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 909
Author(s):  
Anyela Valentina Camargo Rodriguez

Senescence is the final stage of leaf development and is critical for plants’ fitness as nutrient relocation from leaves to reproductive organs takes place. Although senescence is key in nutrient relocation and yield determination in cereal grain production, there is limited understanding of the genetic and molecular mechanisms that control it in major staple crops such as wheat. Senescence is a highly orchestrated continuum of interacting pathways throughout the lifecycle of a plant. Levels of gene expression, morphogenesis, and phenotypic development all play key roles. Yet, most studies focus on a short window immediately after anthesis. This approach clearly leaves out key components controlling the activation, development, and modulation of the senescence pathway before anthesis, as well as during the later developmental stages, during which grain development continues. Here, a computational multiscale modelling approach integrates multi-omics developmental data to attempt to simulate senescence at the molecular and plant level. To recreate the senescence process in wheat, core principles were borrowed from Arabidopsis Thaliana, a more widely researched plant model. The resulted model describes temporal gene regulatory networks and their effect on plant morphology leading to senescence. Digital phenotypes generated from images using a phenomics platform were used to capture the dynamics of plant development. This work provides the basis for the application of computational modelling to advance understanding of the complex biological trait senescence. This supports the development of a predictive framework enabling its prediction in changing or extreme environmental conditions, with a view to targeted selection for optimal lifecycle duration for improving resilience to climate change.


Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Samy Sayed ◽  
Sayed-Ashraf Elarrnaouty ◽  
Saad AlOtaibi ◽  
Mohamed Salah

This study aimed to estimate the virulence of an indigenous Beauveria bassiana on all developmental stages of two indigenous coccinellids; Coccinella undecimpunctata and Hippodamia variegata through three application methods; direct spray, contact method, and feeding on aphids treated with the fungus (ingestion). Also, indirect effect on all developmental stages resulted from 1st larval instar treated with these application methods. All treatments were done with a concentration of 1 × 105 which was recommended in previous studies for different aphid species with a control of 0.02% Tween 80 (v/v). The mortality of 1st larval instar of both H. variegata and C. undecimpunctata and pupal stage of C. undecimpunctata were significantly increased with spray method only. Also, contact method achieved significantly higher mortality on 1st larval instar of C. undecimpunctata only. Regard to indirect effect, except of mortality of 1st larval instar of both predators and 2nd larval instar of H. variegata, other developmental instars/stages of both predators were not affected by B. bassiana through the three tested application methods in the mortality, duration, survival, cumulative survival male and female longevity, and fecundity. Therefore, both tested predatory coccinellids could be compatible with this indigenous isolate of B. bassiana where, in general, there are no negative effects of the fungus on both predators.


2014 ◽  
Vol 104 (9) ◽  
pp. 964-969 ◽  
Author(s):  
Yosuke Matsushita ◽  
Shinya Tsuda

Embryo infection is important for efficient seed transmission of viroids. To identify the major pattern of seed transmission of viroids, we used in situ hybridization to histochemically analyze the distribution of Potato spindle tuber viroid (PSTVd) in each developmental stage of petunia (flowering to mature seed stages). In floral organs, PSTVd was present in the reproductive tissues of infected female × infected male and infected female × healthy male but not of healthy female × infected male before embryogenesis. After pollination, PSTVd was detected in the developed embryo and endosperm in all three crosses. These findings indicate that PSTVd is indirectly delivered to the embryo through ovule or pollen during the development of reproductive tissues before embryogenesis but not directly through maternal tissues as cell-to-cell movement during embryogenesis.


1933 ◽  
Vol s2-76 (301) ◽  
pp. 35-61
Author(s):  
DEV RAJ MEHTA

A general account of the internal reproductive organs and the external genitalia and their development is given. The ‘penis lobes’ develop earlier than the ‘valvae lobes’, and independently of them. The tegumen is the modified ninth tergite. The tenth segment is visibly distinguished into a tergal and sternal part in the pupal stages, and the anal tube passes between the two sclerites. The uncus and the gnathos are dorsal and ventral processes respectively of the tenth segment. The anellus lobes develop as lateral processes of the ninth sternite on either side of the penis. The vasa deferentia during larval life do not extend beyond the eighth abdominal segment and lie in a latero-ventral position. They meet the extensions from the ectodermal ‘ductus ejaculatorius duplex’ during the last larval stadium. From the earliest caterpillar stage there exists a pair of ectodermal ducts formed by the differentiation of the epidermis on the ninth sternite. Towards the end of larval life they divide by constriction to form the accessory glands and the ‘ductus ejaculatory duplex’. At this stage they extend on either side to meet the vasa deferentia. The vesiculae seminales develop by distension from the region of junction between the vasa deferentia and the proximal portion of the ejaculatory duct. The ‘ductus ejaculatorius simplex’ arises as an ectodermal invagination between the pair of ‘penis lobes’ during the final larval instar. It is established that, with the exception of the vasa deferentia, all the remaining elements in the efferent genital system are derived from the ectoderm.


2013 ◽  
Vol 47 (1) ◽  
pp. 24-34
Author(s):  
I. V. Dolinskaya

Abstract Larval cranial setae of each larval instar of 66 species belonging to 35 genera of Palaeartic Notodontid moths from Ukraine and Far East of Russia (Primorskii krai) was examined with the use of a scanning electron microscope. A comparison with outgroup species - Lasiocampoidea (Lasiocampidae), Sphingoidea (Sphingidae) and Noctuoidea (Erebidae: Lymantriinae, Arctiinae; Noctuidae) is conducted. Main kinds of setae during larval development and their transformation are discussed. Possible apomorphic and plesiomorphic states of the different characters are discussed in relation to the different taxa.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yufeng Shi ◽  
Xiaolan Jiang ◽  
Linbo Chen ◽  
Wei-Wei Li ◽  
Sanyan Lai ◽  
...  

Flavonoids, including flavonol derivatives, are the main astringent compounds of tea and are beneficial to human health. Many researches have been conducted to comprehensively identify and characterize the phenolic compounds in the tea plant. However, the biological function of tea flavonoids is not yet understood, especially those accumulated in floral organs. In this study, the metabolic characteristics of phenolic compounds in different developmental stages of flower buds and various parts of the tea flower were investigated by using metabolomic and transcriptomic analyses. Targeted metabolomic analysis revealed varying accumulation patterns of different phenolic polyphenol compounds during flowering; moreover, the content of flavonol compounds gradually increased as the flowers opened. Petals and stamens were the main sites of flavone and flavonol accumulation. Compared with those of fertile flowers, the content of certain flavonols, such as kaempferol derivatives, in anthers of hybrid sterile flowers was significantly low. Transcriptomic analysis revealed different expression patterns of genes in the same gene family in tea flowers. The CsFLSb gene was significantly increased during flowering and was highly expressed in anthers. Compared with fertile flowers, CsFLSb was significantly downregulated in sterile flowers. Further functional verification of the three CsFLS genes indicated that CsFLSb caused an increase in flavonol content in transgenic tobacco flowers and that CsFLSa acted in leaves. Taken together, this study highlighted the metabolic properties of phenolic compounds in tea flowers and determined how the three CsFLS genes have different functions in the vegetative and reproductive organs of tea plants. Furthermore, CsFLSb could regulated flavonol biosynthesis in tea flowers, thus influencing fertility. This research is of great significance for balancing the reproductive growth and vegetative growth of tea plants.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12298
Author(s):  
Maokai Yan ◽  
Xingyue Jin ◽  
Yanhui Liu ◽  
Huihuang Chen ◽  
Tao Ye ◽  
...  

Background Sugarcane (Saccharum spontaneum L.), the major sugar and biofuel feedstock crop, is cultivated mainly by vegetative propagation worldwide due to the infertility of female reproductive organs resulting in the reduction of quality and output of sugar. Deciphering the gene expression profile during ovule development will improve our understanding of the complications underlying sexual reproduction in sugarcane. Optimal reference genes are essential for elucidating the expression pattern of a given gene by quantitative real-time PCR (qRT-PCR). Method In this study, based on transcriptome data obtained from sugarcane ovule, eighteen candidate reference genes were identified, cloned, and their expression levels were evaluated across five developmental stages ovule (AC, MMC, Meiosis, Mitosis, and Mature). Results Our results indicated that FAB2 and MOR1 were the most stably expressed genes during sugarcane female gametophyte development. Moreover, two genes, cell cycle-related genes REC8 and CDK, were selected, and their feasibility was validated. This study provides important insights into the female gametophyte development of sugarcane and reports novel reference genes for gene expression research on sugarcane sexual reproduction.


Author(s):  
Ottavia Romoli ◽  
Johan Claes Schönbeck ◽  
Siegfried Hapfelmeier ◽  
Mathilde Gendrin

AbstractThe mosquito microbiota impacts the physiology of its host and is essential for normal larval development, thereby influencing transmission of vector-borne pathogens. Germ-free mosquitoes generated with current methods show larval stunting and developmental deficits. Therefore, functional studies of the mosquito microbiota have so far mostly been limited to antibiotic treatments of emerging adults. In this study, we developed a novel approach to produce germ-free Aedes aegypti mosquitoes. It is based on reversible colonisation with bacteria genetically modified to allow complete decolonisation at any developmental stage. We show that, unlike germ-free mosquitoes previously produced using sterile diets, reversibly colonised mosquitoes show no developmental retardation and reach the same size as control adults. This allowed us to uncouple the study of the microbiota in larvae and adults. In adults, we detected no impact of bacterial colonisation on mosquito fecundity or longevity. In larvae, we performed a transcriptome analysis and diet supplementation experiments following decolonisation during the third larval instar. Our data suggest that bacteria support larval development by contributing to folate biosynthesis and by enhancing energy storage. Our study establishes a novel tool to study the microbiota in insects and deepens our knowledge on the metabolic contribution of bacteria to mosquito development.


Author(s):  
Jiří Skuhrovec ◽  
Ondřej Douda ◽  
Miloslav Zouhar ◽  
Marie Maňasová ◽  
Matěj Božik ◽  
...  

Abstract The Colorado potato beetle ranks as one of the most important potato pests, mainly due to its high feeding rate during all developmental stages, particularly third and fourth larval instar, and high fecundity. The effect of essential oil (EO) from anise (Pimpinella anisum L. [Apiales: Apiaceae]) prepared as conventional and encapsulated (EN) formulations on the mortality and antifeedant responses of young larvae of Colorado potato beetles was studied to evaluate the insecticidal and antifeedant effects of five concentrations of this EO and to assess the persistence of both formulations on potato plants. The EN formulation had a significantly higher residual amount compared with that of the conventionally formulated EO. Significantly different values of LC50 and LC90 (ppm) were established for the EO (LC50 = 1,700 and LC90 = 9500) and EN (LC50 = 3,100 and LC90 = 14,300) formulations. The effects of both P. anisum formulations (EO and EN) applied topically to Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) larvae were distinctly different from those observed with the contact treatment. At the highest concentration of 20,000 ppm, the mortality of the second instars of the L. decemlineata larvae did not exceed 25%. On the other hand, both tested formulations of P. anisum were highly effective when administered orally. The encapsulated EO formulation achieved a distinctly higher biological activity. Our results confirm that the EO from P. anisum, especially the encapsulated formulation, has high insecticidal properties that may lead to the development of new organic products for the control of Colorado potato beetles.


1988 ◽  
Vol 9 (4) ◽  
pp. 385-403 ◽  
Author(s):  
Zbynek Rocek

AbstractThe frontoparietal is a unique feature of anurans, not only if this group is compared with other amphibians, but also with other vertebrates as well. It is often used as an important character in anuran systematics. However, little is still known about its evolutionary origin and significance. This is the reason why its state in Triadobatrachus and fossil anurans was examined, and compared with the condition in osteolepiforms and labyrinthodonts. Besides that also an information from the larval development was taken into consideration. It follows from all these data that the frontoparietal in adult anurans is a compound bone; the originally independent elements forming it (frontals, parietals, and some other ones) either coalesced with each other, or have disappeared during the course of evolution, often in convergent fashion. As the original state is better reflected in early developmental stages, one may suppose that larval condition also better reflects phylogenetic relations than the definitive bone complex of adults.


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