1
|
Horn T, Narov KD, Panfilio KA. Persistent Parental RNAi in the Beetle Tribolium castaneum Involves Maternal Transmission of Long Double-Stranded RNA. ADVANCED GENETICS (HOBOKEN, N.J.) 2022; 3:2100064. [PMID: 36620196 PMCID: PMC9744488 DOI: 10.1002/ggn2.202100064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Indexed: 01/11/2023]
Abstract
Parental RNA interference (pRNAi) is a powerful and widely used method for gene-specific knockdown. Yet in insects its efficacy varies between species, and how the systemic response is transmitted from mother to offspring remains elusive. Using the beetle Tribolium castaneum, an RT-qPCR strategy to distinguish the presence of double-stranded RNA (dsRNA) from endogenous mRNA is reported. It is found that injected dsRNA is directly transmitted into the egg and persists throughout embryogenesis. Despite this depletion of dsRNA from the mother, it is shown that strong pRNAi can persist for months before waning at strain-specific rates. In seeking the receptor proteins for cellular uptake of long dsRNA into the egg, a phylogenomics profiling approach of candidate proteins is also presented. A visualization strategy based on taxonomically hierarchical assessment of orthology clustering data to rapidly assess gene age and copy number changes, refined by sequence-based evidence, is demonstrated. Repeated losses of SID-1-like channel proteins in the arthropods, including wholesale loss in the Heteroptera (true bugs), which are nonetheless highly sensitive to pRNAi, are thereby documented. Overall, practical considerations for insect pRNAi against a backdrop of outstanding questions on the molecular mechanism of dsRNA transmission for long-term, systemic knockdown are elucidated.
Collapse
Affiliation(s)
- Thorsten Horn
- Institute for Zoology: Developmental BiologyUniversity of CologneZülpicher Straße 47b50674CologneGermany
| | - Kalin D. Narov
- School of Life SciencesUniversity of WarwickGibbet Hill CampusCoventryCV4 7ALUK
| | - Kristen A. Panfilio
- Institute for Zoology: Developmental BiologyUniversity of CologneZülpicher Straße 47b50674CologneGermany,School of Life SciencesUniversity of WarwickGibbet Hill CampusCoventryCV4 7ALUK
| |
Collapse
|
2
|
Maeno KO, Piou C, Ghaout S. Allocation of more reproductive resource to egg size rather than clutch size of gregarious desert locust (Schistocerca gregaria) through increasing oogenesis period and oosorption rate. JOURNAL OF INSECT PHYSIOLOGY 2022; 136:104331. [PMID: 34838517 DOI: 10.1016/j.jinsphys.2021.104331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/24/2021] [Accepted: 11/19/2021] [Indexed: 06/13/2023]
Abstract
The desert locust, Schistocerca gregaria, shows a density-dependent reproductive trade-off by laying fewer but larger eggs in crowded conditions (gregarious phase) than in isolated conditions (solitarious phase). However, the physiological mechanisms controlling reproductive resource allocation remain unclear. We examined how egg production processes, including ovulation timing (i.e., oogenesis period), oocyte and ovarian growth rates, and oosorption rate (resorbing developing terminal oocytes), regulate reproductive outputs (egg biomass per clutch, egg size, and clutch size) during a reproductive cycle in S. gregaria by rearing them either under isolated or crowded conditions. We observed a common density-dependent negative correlation between egg size and clutch size, with no significant difference in egg biomass between the two rearing conditions. Dissection of female locusts after different days of oviposition revealed that the daily oocyte growth rate was almost similar between the two rearing conditions, but crowd-reared females ovulated later than isolated-reared ones, resulting in further oocyte growth in the former. Terminal oocytes were renewed by previous penultimate oocytes at the onset of a new reproductive cycle, and oosorption mainly occurred at an early stage in both rearing conditions; however, crowd-reared locusts displayed higher levels of oosorption compared to their isolated-reared counterparts. Crowding induced a high oosorption rate, resulting in a reduced clutch size and a prolonged oogenesis period, which in turn allowed oocytes to intake more yolk, which was probably recycled via oosorption. These results suggest that the length of the oogenesis period and oosorption rate are manipulated by maternal density, and these physiological modifications interactively regulate reproductive trade-off in S. gregaria.
Collapse
Affiliation(s)
- Koutaro Ould Maeno
- Japan International Research Center for Agricultural Sciences (JIRCAS), Livestock and Environment Division, Ohwashi 1-1, Tsukuba, Ibaraki 305-8686, Japan.
| | - Cyril Piou
- CIRAD, UMR CBGP, INRAE, Institut Agro, IRD, Université Montpellier, F-34398 Montpellier, France; Ibn Zohr University, Agadir, Morocco; Centre National de Lutte Antiacridienne (CNLAA), Aït-Melloul, BP 125, Inezgane, Agadir, Morocco
| | - Saïd Ghaout
- Centre National de Lutte Antiacridienne (CNLAA), Aït-Melloul, BP 125, Inezgane, Agadir, Morocco
| |
Collapse
|
3
|
Gijbels M, Schellens S, Schellekens T, Bruyninckx E, Marchal E, Vanden Broeck J. Precocious Downregulation of Krüppel-Homolog 1 in the Migratory Locust, Locusta migratoria, Gives Rise to An Adultoid Phenotype with Accelerated Ovarian Development but Disturbed Mating and Oviposition. Int J Mol Sci 2020; 21:E6058. [PMID: 32842716 PMCID: PMC7503607 DOI: 10.3390/ijms21176058] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 01/29/2023] Open
Abstract
Krüppel-homolog 1 (Kr-h1) is a zinc finger transcription factor maintaining the status quo in immature insect stages and promoting reproduction in adult insects through the transduction of the Juvenile Hormone (JH) signal. Knockdown studies have shown that precocious silencing of Kr-h1 in the immature stages results in the premature development of adult features. However, the molecular characteristics and reproductive potential of these premature adult insect stages are still poorly understood. Here we report on an adult-like or 'adultoid' phenotype of the migratory locust, Locusta migratoria, obtained after a premature metamorphosis induced by the silencing of LmKr-h1 in the penultimate instar. The freshly molted adultoid shows precocious development of adult features, corresponding with increased transcript levels of the adult specifier gene LmE93. Furthermore, accelerated ovarian maturation and vitellogenesis were observed in female adultoids, coinciding with elevated expression of LmCYP15A1 in corpora allata (CA) and LmKr-h1 and vitellogenin genes (LmVg) in fat body, whereas LmE93 and Methoprene-tolerant (LmMet) transcript levels decreased in fat body. In adultoid ovaries, expression of the Halloween genes, Spook (LmSpo) and Phantom (LmPhm), was elevated as well. In addition, the processes of mating and oviposition were severely disturbed in these females. L. migratoria is a well-known, swarm-forming pest insect that can destroy crops and harvests in some of the world's poorest countries. As such, a better understanding of factors that are capable of significantly reducing the reproductive potential of this pest may be of crucial importance for the development of novel locust control strategies.
Collapse
Affiliation(s)
- Marijke Gijbels
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000 Leuven, Belgium; (M.G.); (S.S.); (T.S.); (E.B.)
| | - Sam Schellens
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000 Leuven, Belgium; (M.G.); (S.S.); (T.S.); (E.B.)
| | - Tine Schellekens
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000 Leuven, Belgium; (M.G.); (S.S.); (T.S.); (E.B.)
| | - Evert Bruyninckx
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000 Leuven, Belgium; (M.G.); (S.S.); (T.S.); (E.B.)
| | - Elisabeth Marchal
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000 Leuven, Belgium; (M.G.); (S.S.); (T.S.); (E.B.)
- Life Science Technologies, Imec, Kapeldreef 75, B- 3001 Leuven, Belgium
| | - Jozef Vanden Broeck
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000 Leuven, Belgium; (M.G.); (S.S.); (T.S.); (E.B.)
| |
Collapse
|
4
|
Gijbels M, Lenaerts C, Vanden Broeck J, Marchal E. Juvenile Hormone receptor Met is essential for ovarian maturation in the Desert Locust, Schistocerca gregaria. Sci Rep 2019; 9:10797. [PMID: 31346226 PMCID: PMC6658565 DOI: 10.1038/s41598-019-47253-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 07/12/2019] [Indexed: 01/23/2023] Open
Abstract
Juvenile hormones (JH) are key endocrine regulators produced by the corpora allata (CA) of insects. Together with ecdysteroids, as well as nutritional cues, JH coordinates different aspects of insect postembryonic development and reproduction. The function of the recently characterized JH receptor, Methoprene-tolerant (Met), appears to be conserved in different processes regulated by JH. However, its functional interactions with other hormonal signalling pathways seem highly dependent on the feeding habits and on the developmental and reproductive strategies employed by the insect species investigated. Here we report on the effects of RNA interference (RNAi) mediated SgMet knockdown during the first gonadotrophic cycle in female desert locusts (Schistocerca gregaria). This voracious, phytophagous pest species can form migrating swarms that devastate field crops and harvests in several of the world’s poorest countries. A better knowledge of the JH signalling pathway may contribute to the development of novel, more target-specific insecticides to combat this very harmful swarming pest. Using RNAi, we show that the JH receptor Met is essential for ovarian maturation, vitellogenesis and associated ecdysteroid biosynthesis in adult female S. gregaria. Interestingly, knockdown of SgMet also resulted in a significant decrease of insulin-related peptide (SgIRP) and increase of neuroparsin (SgNP) 3 and 4 transcript levels in the fat body, illustrating the existence of an intricate regulatory interplay between different hormonal factors. In addition, SgMet knockdown in females resulted in delayed display of copulation behaviour with virgin males, when compared with dsGFP injected control animals. Moreover, we observed an incapacity of adult dsSgMet injected female locusts to oviposit during the time of the experimental setup. As such, SgMet is an essential gene playing crucial roles in the endocrine communication necessary for successful reproduction of the desert locust.
Collapse
Affiliation(s)
- Marijke Gijbels
- Research group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000, Leuven, Belgium
| | - Cynthia Lenaerts
- Research group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000, Leuven, Belgium
| | - Jozef Vanden Broeck
- Research group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000, Leuven, Belgium.
| | - Elisabeth Marchal
- Research group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Zoological Institute, Naamsestraat 59 box 2465, 3000, Leuven, Belgium. .,Imec, Kapeldreef 75, B- 3001, Leuven, Belgium.
| |
Collapse
|
5
|
Chen B, Ma R, Ma G, Guo X, Tong X, Tang G, Kang L. Haemocyanin is essential for embryonic development and survival in the migratory locust. INSECT MOLECULAR BIOLOGY 2015; 24:517-527. [PMID: 26010377 DOI: 10.1111/imb.12177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Haemocyanins are commonly known as copper-containing oxygen carriers within the haemolymph of arthropods, and have been found in many orders of insects. However, it remains unresolved why haemocyanins persist in insects that possess elaborate tracheal systems for oxygen diffusion to cells. Here we identified haemocyanins in the migratory locust Locusta migratoria that consists of two distinct subunits, Hc1 and Hc2. Genomic sequence analysis indicated that Hc1 and Hc2 have four and three gene copies, respectively, which may have evolved via gene duplication followed by divergent evolution of introns. The two subunits exhibit abundant and embryonic-specific expression at the mRNA and protein level; their expression peaks in the mid-term embryo and is not detectable in the late nymphal and adult stages. A larger proportion of the haemocyanins is present in the yolk compared with that in the embryo. Immunostaining shows that haemocyanins in the embryo are mainly expressed in the epidermis. Knockdown of Hc1 and Hc2 results in significant embryonic developmental delay and abnormality as well as reduced egg hatchability, ie the proportion of hatched eggs. These results reveal a previously unappreciated and fundamental role for haemocyanins in embryonic development and survival in insects, probably involving the exchange of molecules (eg O2 ) between the embryo and its environment.
Collapse
Affiliation(s)
- B Chen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - R Ma
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - G Ma
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Department of Plant Protection, Yunnan Agricultural University, Kunming, China
| | - X Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - X Tong
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - G Tang
- Department of Plant Protection, Yunnan Agricultural University, Kunming, China
| | - L Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
6
|
Jones N, Taub-Montemayor T, Rankin MA. Fluorescein-dextran sequestration in the reproductive tract of the migratory grasshopper Melanoplus sanguinipes (Orthoptera, Acridiidae). Micron 2013; 46:80-4. [DOI: 10.1016/j.micron.2012.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 12/03/2012] [Accepted: 12/03/2012] [Indexed: 11/29/2022]
|
7
|
Fruttero LL, Frede S, Rubiolo ER, Canavoso LE. The storage of nutritional resources during vitellogenesis of Panstrongylus megistus (Hemiptera: Reduviidae): the pathways of lipophorin in lipid delivery to developing oocytes. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:475-486. [PMID: 21277855 DOI: 10.1016/j.jinsphys.2011.01.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 05/30/2023]
Abstract
In this work, we have analyzed the pathways by which lipophorin (Lp) delivers its lipid cargo to developing oocytes of Panstrongylus megistus, a hematophagous vector of Chagas' disease. Lp, vitellin, total lipids and proteins were measured in ovarian tissues at different stages of the reproductive cycle. Localization of Lp in developing oocytes, mainly at their cortical area, was demonstrated by immunofluorescence assays using an anti-Lp antibody labeled with FITC. In vivo approaches injecting fluorescently labeled Lp to follow the course of the entire particle (Lp-DiI or Lp-Oregon Green) or its lipid cargo (Lp-Bodipy-FA) were monitored by laser scanning confocal microscopy. Significant increases in the amounts of lipids, proteins and vitellin were observed in ovarian tissue with the progress of vitellogenesis. Unexpectedly, an increase in the amount of Lp was also observed. The experiments in vivo demonstrated that the uptake of fluorescent Lp labeled on its protein or lipid moiety by developing oocytes occurred very fast, being impaired at low temperatures. The co-injection of fluorescent Lp and vitellogenin (Vg) showed that both particles co-localized inside yolk bodies, confirming the endocytic pathway for Lp. When the fate of lipids transferred to oocytes was evaluated in vitellogenic females by co-injecting Lp-Bodipy-FA and Lp-DiI, the signal for Bodipy-FA was found in both lipid droplets and yolk bodies. In contrast, in injected females kept at 4°C the fluorescence was reduced, being observed exclusively in lipid droplets, implying that lipid transfer to the oocyte was diminished but not abolished. Taken together, the results demonstrate that in the hematophagous P. megistus, the storage of lipid resources by developing oocytes occurs by the convergence of different pathways by which Lp maximizes the delivery of its lipid cargo. In addition, it was also shown that, to some extent, lipids stored in the oocyte lipid droplets can also originate from endocytosed Vg. The relevance of these events in the context of the physiology of reproduction in P. megistus is discussed.
Collapse
Affiliation(s)
- Leonardo L Fruttero
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología, Facultad de Ciencias Químicas-Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina
| | | | | | | |
Collapse
|