Symbiotic bacteria are important drivers of phenotypic diversity in insects. One of the widespread symbionts to have emerged belongs to the genus Arsenophonus, however, its biological functions in most host insects remain entirely unknown. Here we report two distinct Arsenophonus strains in the brown planthopper (BPH), Nilaparvata lugens, a major pest insect in Asian countries that causes significant economic damage through rice crop destruction. Genomic resequencing data suggested that one Arsenophonus strain (S-type) negatively affected the insecticide resistance of the host. Indeed, replacement of the resident Arsenophonus with the S-type Arsenophonus significantly decreased host insecticide resistance. Transcriptome and metabolome analysis revealed down-regulation of xenobiotic metabolism and increased amino acid accumulation in the S-type Arsenophonus infected host. This study demonstrates how a symbiont-mediated phenotypic change can occur. The results of this study will aid in developing strategies that work through imposing an ecological disadvantage on insect pests, which will be of great value for pest control in agricultural industry.
Introduction
The brown planthopper (BPH,
Nilaparvata lugens
Stål, Hemiptera: Delphacidae) is one of the most devastating insect pests of the crucially important cereal crop, rice (
Oryza sativa
L.). Currently, multiple BPH-resistant rice varieties have been cultivated and generalized to control BPH. However, the defence metabolic responses and their modes of action against BPH in different rice cultivars remain uncharacterized.
Objective
We used a non-biased metabolomics approach to explore the differences in metabolite profiles in response to BPH infestation in the susceptible TN1 rice cultivar and two resistant cultivars (IR36 and IR56).
Methods
The metabolomic detection based on gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–mass spectrometry (LC–MS) was performed to investigate the content changes of identified metabolites in TN1, IR36 and IR56 rice varieties at various time points (0 h, 24 h, 48 h and 96 h) post BPH feeding. The differentially expressed metabolites were screened and the corresponding metabolic pathways were further enriched.
Results
The results showed that compared to that in TN1, the content changes of most primary metabolites were more stable, but the concentration alterations of some defence-related metabolites were more acute and persistent in IR36 and IR56. Furthermore, the differentially expressed pathways analysis revealed that cyanoamino acids and lipids metabolism was persistently induced in IR36, but changes in thiamine, taurine and hypotaurine metabolism were more significant in IR56 during BPH infestation. Besides, the contents of quercetin and spermidine which were harmful to BPH fitness, were significantly elevated by BPH in TN1 and IR36, and the quercetin level was significantly decreased during BPH feeding in IR56.
Conclusion
The results of the differences in metabolite profiles in response to BPH infestation in different rice cultivars were useful to clarify the metabolic mechanism of rice plants during BPH infestation and to provide new resources to control this insect pest.
Electronic supplementary material
The online version of this article (10.1007/s11306-019-1523-4) contains supplementary material, which is available to authorized users.
Purpose Human embryonic stem cells (hESCs) are selfrenewing, pluripotent cells that are valuable research tools and hold promise for use in regenerative medicine. The need for new hESC lines motivated our attempts to find a new resource for the derivation of hESC lines. The aim of this work was to establish more hESC lines from abnormal fertilized zygotes and to meet the emerging requirements for their use in cell replacement therapies, disease modeling, and basic research. Methods A total of 130 tripronuclear human zygotes was collected 18-20 h post-insemination and cultured in a modified culture medium. The inner cell mass of 12 blastocysts were isolated by a mechanical method in order to establish embryonic stem cell lines. Results We established four hESC lines derived from 130 trinuclear zygotes, one of which was triploid and the others were diploid. The efficiency of deriving hESC lines is 3.08%. The ratio of deriving triploid and diploid hESC lines is 1:3. All of these hESC lines exhibited similar markers of undifferentiated hESCs and had the typical morphology of hESCs, a capacity for long-term proliferation, and pluripotent differentiation potential both in vivo and in vitro.Conclusions These abnormal zygotes, which otherwise would have been discarded, can serve as an alternative source for normal euploid hESC lines.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.