Culture and manipulation of insect facultative symbionts

Pontes, Mauricio H.; Dale, Colin

doi:10.1016/j.tim.2006.07.004

Cited by 68 publications

(72 citation statements)

References 52 publications

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“…Meanwhile, the molecular mechanisms underlying insect-microbe interactions are much less well understood, because most of these insect mutualistic symbionts are neither culturable nor genetically manipulatable. Recent studies have succeeded in the isolation of several facultative symbionts by using insect cell lines or axenic media (27,29,32,57,65,87,92), revolutionizing studies of insect endosymbiosis. The present article reviews the amazing diversity of bacterial endosymbiosis in insects, focusing on several model systems with culturable endosymbionts, which provides a new perspective regarding how intimate symbiotic associations may have evolved and how they are maintained within insects.…”

Section: Introductionmentioning

confidence: 99%

Endosymbiotic Bacteria in Insects: Their Diversity and Culturability

2009

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Many animals and plants possess symbiotic microorganisms inside their body, wherein intimate interactions occur between the partners. The Insecta, often rated as the most diverse animal group, show various types of endosymbiotic associations, ranging from obligate mutualism to facultative parasitism. Although technological advancements in culture-independent molecular techniques, such as quantitative PCR, molecular phylogeny and in situ hybridization, as well as genomic and metagenomic analyses, have allowed us to directly observe endosymbiotic associations in vivo, the molecular mechanisms underlying insect-microbe interactions are not well understood, because most of these insect endosymbionts are neither culturable nor genetically manipulatable. However, recent studies have succeeded in the isolation of several facultative symbionts by using insect cell lines or axenic media, revolutionizing studies of insect endosymbiosis. This article reviews the amazing diversity of bacterial endosymbiosis in insects, focusing on several model systems with culturable endosymbionts, which provide a new perspective towards understanding how intimate symbiotic associations may have evolved and how they are maintained within insects.

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Section: Introductionmentioning

confidence: 99%

Endosymbiotic Bacteria in Insects: Their Diversity and Culturability

2009

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“…Most insect symbionts are generally transmitted from mother to offspring and are highly adapted to unique ecological niches within their hosts (1). Thus, it is not easy to culture them in vitro, and consequently, they tend to be neither genetically tractable nor manipulatable (2,3). On the other hand, every generation of the bean bug Riptortus pedestris (Hemiptera: Alydidae) acquires its betaproteobacterial genus Burkholderia symbionts from the environment and harbors them exclusively in a specialized region (the M4 region) of the posterior midgut, which contains numerous crypts (4).…”

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confidence: 99%

Purine Biosynthesis, Biofilm Formation, and Persistence of an Insect-Microbe Gut Symbiosis

Kim

Kwon

Kim

et al. 2014

Appl Environ Microbiol

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cThe Riptortus-Burkholderia symbiotic system is an experimental model system for studying the molecular mechanisms of an insect-microbe gut symbiosis. When the symbiotic midgut of Riptortus pedestris was investigated by light and transmission electron microscopy, the lumens of the midgut crypts that harbor colonizing Burkholderia symbionts were occupied by an extracellular matrix consisting of polysaccharides. This observation prompted us to search for symbiont genes involved in the induction of biofilm formation and to examine whether the biofilms are necessary for the symbiont to establish a successful symbiotic association with the host. To answer these questions, we focused on purN and purT, which independently catalyze the same step of bacterial purine biosynthesis. When we disrupted purN and purT in the Burkholderia symbiont, the ⌬purN and ⌬purT mutants grew normally, and only the ⌬purT mutant failed to form biofilms. Notably, the ⌬purT mutant exhibited a significantly lower level of cyclic-di-GMP (c-di-GMP) than the wild type and the ⌬purN mutant, suggesting involvement of the secondary messenger c-di-GMP in the defect of biofilm formation in the ⌬purT mutant, which might operate via impaired purine biosynthesis. The host insects infected with the ⌬purT mutant exhibited a lower infection density, slower growth, and lighter body weight than the host insects infected with the wild type and the ⌬purN mutant. These results show that the function of purT of the gut symbiont is important for the persistence of the insect gut symbiont, suggesting the intricate biological relevance of purine biosynthesis, biofilm formation, and symbiosis.

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“…These microbial associates are usually transmitted from mothers to offspring vertically and exert various biological effects on their host insects: some play essential roles like provisioning of essential nutrients (3); others have conditionally beneficial roles such as defense against natural enemies and adaptation to specific ecological conditions (4); and others induce parasitic or pathogenic consequences including negative fitness effects and reproductive aberrations (5). The majority of these symbionts are difficult to culture in vitro, probably because they are highly adapted to the unique environment within their host insects (6,7). Consequently, biological roles of the symbionts were investigated mainly using experimental and physiological approaches to the whole host-symbiont systems (8).…”

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confidence: 99%

Polyester synthesis genes associated with stress resistance are involved in an insect–bacterium symbiosis

Kim

Won

Nikoh

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Significance This study reports a previously unrecognized involvement of polyhydroxyalkanoate (PHA), known as a bacterial endocellular storage polymer, in an insect–bacterium symbiosis. Many bacteria in the environment accumulate PHA granules within their cells, which provide resistance to nutritional depletion and other environmental stresses. Here we demonstrate that synthesis and accumulation of PHA in the symbiont cells are required for normal symbiotic association with, and, consequently, positive fitness effects for the host insect. The requirement of PHA for symbiosis suggests that, contrary to the general expectation, the within-host environment may be, at least in some aspects, stressful for the symbiotic bacteria.

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Culture and manipulation of insect facultative symbionts

Cited by 68 publications

References 52 publications

Endosymbiotic Bacteria in Insects: Their Diversity and Culturability

Endosymbiotic Bacteria in Insects: Their Diversity and Culturability

Purine Biosynthesis, Biofilm Formation, and Persistence of an Insect-Microbe Gut Symbiosis

Polyester synthesis genes associated with stress resistance are involved in an insect–bacterium symbiosis

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