GENETICS, PHYSIOLOGY, AND EVOLUTIONARY RELATIONSHIPS OF THE GENUS <i>BUCHNERA</i>: Intracellular Symbionts of Aphids

Baumann, Paul; Baumann, Linda C.; Lai, Chi Yung; Rouhbakhsh, Dadbeh; Moran, Nancy A.; Clark, Marta A.

doi:10.1146/annurev.mi.49.100195.000415

Cited by 474 publications

(359 citation statements)

References 47 publications

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“…Genomic and physiological research reveals that Buchnera synthesizes essential amino acids for its host (6,7,(9)(10)(11)(12)). Buchnera's genome includes genes for almost all enzymes in the essential amino acid pathways and for enzymes in pathways for the nonessential amino acids tyrosine, glycine, and cysteine (6).…”

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confidence: 99%

Aphid genome expression reveals host–symbiont cooperation in the production of amino acids

Hansen

Moran

2011

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

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The evolution of intimate symbiosis requires the coordination of gene expression and content between the distinct partner genomes; this coordination allows the fusion of capabilities of each organism into a single integrated metabolism. In aphids, the 10 essential amino acids are scarce in the phloem sap diet and are supplied by the obligate bacterial endosymbiont ( Buchnera ), which lives inside specialized cells called bacteriocytes. Although Buchnera ’s genome encodes most genes for essential amino acid biosynthesis, several genes in essential amino acid pathways are missing, as are most genes for production of nonessential amino acids. Additionally, it is unresolved whether the supply of nitrogen for amino acid biosynthesis is supplemented by recycling of waste ammonia. We compared pea aphid gene expression between bacteriocytes and other body tissues using RNA sequencing and pathway analysis and exploiting the genome sequences available for both partners. We found that 26 genes underlying amino acid biosynthesis were up-regulated in bacteriocytes. Seven of these up-regulated genes fill the gaps of Buchnera ’s essential amino acid pathways. In addition, genes underlying five nonessential amino acid pathways lost from Buchnera are up-regulated in bacteriocytes. Finally, our results reveal that two genes, glutamine synthetase and glutamate synthase, which potentially work together in the incorporation of ammonium nitrogen into glutamate (GOGAT) cycle to assimilate ammonia into glutamate, are up-regulated in bacteriocytes. Thus, host gene expression and symbiont capabilities are closely integrated within bacteriocytes, which function as specialized organs of amino acid production. Furthermore, the GOGAT cycle may be a key source of nitrogen fueling the integrated amino acid metabolism of the aphid– Buchnera partnership.

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confidence: 99%

Aphid genome expression reveals host–symbiont cooperation in the production of amino acids

Hansen

Moran

2011

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

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476

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“…Some symbioses involve bacteria that are universal within individuals of a host species. Prominent examples are found in sap-feeding insects in the order Hemiptera, which depend on bacterial symbionts to synthesize essential amino acids and other nutrients that are absent or rare in their specialized diets of plant sap (1,4,5). In many of these insects, the vertical transmission of bacterial symbionts from mother to offspring over millions of years has resulted in very intimate associations such that neither organism is capable of growth and reproduction without the other (6-9).…”

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Intraspecific genetic variation in hosts affects regulation of obligate heritable symbionts

Chong

Moran

2016

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

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Symbiotic relationships promote biological diversification by unlocking new ecological niches. Over evolutionary time, hosts and symbionts often enter intimate and permanent relationships, which must be maintained and regulated for both lineages to persist. Many insect species harbor obligate, heritable symbiotic bacteria that provision essential nutrients and enable hosts to exploit niches that would otherwise be unavailable. Hosts must regulate symbiont population sizes, but optimal regulation may be affected by the need to respond to the ongoing evolution of symbionts, which experience high levels of genetic drift and potential selection for selfish traits. We address the extent of intraspecific variation in the regulation of a mutually obligate symbiosis, between the pea aphid (Acyrthosiphon pisum) and its maternally transmitted symbiont, Buchnera aphidicola. Using experimental crosses to identify effects of host genotypes, we measured symbiont titer, as the ratio of genomic copy numbers of symbiont and host, as well as developmental time and fecundity of hosts. We find a large (>10-fold) range in symbiont titer among genetically distinct aphid lines harboring the same Buchnera haplotype. Aphid clones also vary in fitness, measured as developmental time and fecundity, and genetically based variation in titer is correlated with host fitness, with higher titers corresponding to lower reproductive rates of hosts. Our work shows that obligate symbiosis is not static but instead is subject to short-term evolutionary dynamics, potentially reflecting coevolutionary interactions between host and symbiont.

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“…Bacillus spp are common inhabitants of different mosquito species from different habitats (Takahiro et al 2006). The bacteria play vital roles in digestion and growth factor production, immune response in their host and also protect from harmful microbes by producing anti-microbial products (Baumann et al 1995;Rajagopal 2009). Natural chemicals that transfer information between organisms are generally classified as semiochemicals (Regnier 1971 2004).…”

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confidence: 99%

Characterization and control of symbiotic Bacillus cereus isolated from the mid gut of Anopheles subpictus Grassi

Mukhopadhyay

Chatterjee

2016

J Parasit Dis

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An investigation was done to find out the role of gut bacterium on the larval development and survival of Anopheles subpictus, the vector responsible for the transmission of malaria. An. subpictus mosquitoes breed exclusively in stagnant water, including shrimp/fish ponds with high nutrient level. One bacterial strain (CX2) was isolated from the midgut of late third instar of mosquito larvae. The bacterial isolate was sensitive to recommended doses of tetracyclin (30 lg/disc), doxycycline (30 lg/disc), kanamycin (30 lg/disc), gentamycin (10 lg/disc), streptomycin (10 lg/disc), vancomycin (30 lg/disc), ofloxacin (5 lg/disc), levofloxacin (5 lg/disc), gatifloxacin (10 lg/ disc), but resistant to ampicillin (10 lg/disc).The larvae which were fed with the mixture of two antibiotics tetracylin (30 lg/disc) and doxycyclin (30 lg/disc) (1:1) could not survive in rice-field water. In the control experiments without any antibiotic treatment, 95-100 % survival and 95 % adult emergence were observed. The study indicates that the elimination of gut bacteria suppressed larval growth. Phylogenetic analysis of the 16S rRNA gene sequence was also done. Based on the morphological, biochemical, FAME analysis and phylogenetic analysis, the bacterial isolate CX2 was identified as Bacillus cereus. Poly acrylamide gel electrophoresis analysis revealed that the isolate showed discrete bands ranging from 24.272 to 60.049 kDa proteins. Water extract and methanol extract of Tamarindus indica showed inhibitory effect against B. cereus.

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GENETICS, PHYSIOLOGY, AND EVOLUTIONARY RELATIONSHIPS OF THE GENUS BUCHNERA: Intracellular Symbionts of Aphids

Cited by 474 publications

References 47 publications

Aphid genome expression reveals host–symbiont cooperation in the production of amino acids

Aphid genome expression reveals host–symbiont cooperation in the production of amino acids

Intraspecific genetic variation in hosts affects regulation of obligate heritable symbionts

Characterization and control of symbiotic Bacillus cereus isolated from the mid gut of Anopheles subpictus Grassi

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