Dietary specialization and <i>Eucalyptus</i> species preferences in Queensland koalas (<i>Phascolarctos cinereus</i>)

Higgins, Alexis L.; Bercovitch, Fred B.; Tobey, Jennifer R.; Andrus, Chris Hamlin

doi:10.1002/zoo.20312

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…For example, the concentration of total FPCs was the most important variable determining feeding by marsupial folivores on Eucalyptus species (Lawler et al, 2000; Moore et al, 2005; Jensen et al, 2015), and were implicated in habitat patchiness in Australian forests (Lawler et al, 2000). Interestingly, the highest concentrations of total FPCs in this study were found in four koala-preferred species: E. camphora, E. globulus, E. camaldulensis , and E. viminalis (Moore et al, 2004a; Higgins et al, 2011). This could reflect the ongoing “arms race” between plant and herbivore, where koalas can tolerate significant levels of these compounds.…”

Section: Discussionmentioning

confidence: 56%

Quantification and Localization of Formylated Phloroglucinol Compounds (FPCs) in Eucalyptus Species

et al. 2019

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The Eucalyptus genus is a hyper-diverse group of long-lived trees from the Myrtaceae family, consisting of more than 700 species. Eucalyptus are widely distributed across their native Australian landscape and are the most widely planted hardwood forest trees in the world. The ecological and economic success of Eucalyptus trees is due, in part, to their ability to produce a plethora of specialized metabolites, which moderate abiotic and biotic interactions. Formylated phloroglucinol compounds (FPCs) are an important class of specialized metabolites in the Myrtaceae family, particularly abundant in Eucalyptus . FPCs are mono- to tetra-formylated phloroglucinol based derivatives, often with an attached terpene moiety. These compounds provide chemical defense against herbivory and display various bioactivities of pharmaceutical relevance. Despite their ecological and economic importance, and continued improvements into analytical techniques, FPCs have proved challenging to study. Here we present a simple and reliable method for FPCs extraction, identification and quantification by UHPLC-DAD-ESI-Q-TOF-MS/MS. The method was applied to leaf, flower bud, and flower samples of nine different eucalypt species, using a small amount of plant material. Authentic analytical standards were used to provide high resolution mass spectra and fragmentation patterns. A robust method provides opportunities for future investigations into the identification and quantification of FPCs in complex biological samples with high confidence. Furthermore, we present for the first time the tissue-based localization of FPCs in stem, leaf, and flower bud of Eucalyptus species measured by mass spectrometry imaging, providing important information for biosynthetic pathway discovery studies and for understanding the role of those compounds in planta .

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Section: Discussionmentioning

confidence: 56%

Quantification and Localization of Formylated Phloroglucinol Compounds (FPCs) in Eucalyptus Species

et al. 2019

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“…Eucalyptus foliage has been described as an “unpromising” dietary source, low in nutrients and proteins but at the same time rich in oils and secondary plant compounds, such as lignin, cellulose and tannins, which are toxic to most animals 1 2 . Koalas have evolved a set of behavioral, physiological, morphological and metabolic adaptations to such a diet 3 . For example, they have a specialized digestive tract with an extremely enlarged caecum 4 and very long retention times of food within the gut 5 .…”

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confidence: 99%

Variation in koala microbiomes within and between individuals: effect of body region and captivity status

Alfano

Courtiol

Vielgrader³

et al. 2015

Sci Rep

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Metagenomic analysis of 16S ribosomal RNA has been used to profile microbial communities at high resolution, and to examine their association with host diet or diseases. We examined the oral and gut microbiome composition of two captive koalas to determine whether bacterial communities are unusual in this species, given that their diet consists almost exclusively of Eucalyptus leaves. Despite a highly specialized diet, koala oral and gut microbiomes were similar in composition to the microbiomes from the same body regions of other mammals. Rectal swabs contained all of the diversity present in faecal samples, along with additional taxa, suggesting that faecal bacterial communities may merely subsample the gut bacterial diversity. Furthermore, the faecal microbiomes of the captive koalas were similar to those reported for wild koalas, suggesting that captivity may not compromise koala microbial health. Since koalas frequently suffer from ocular diseases caused by Chlamydia infection, we also examined the eye microbiome composition of two captive koalas, establishing the healthy baseline for this body part. The eye microbial community was very diverse, similar to other mammalian ocular microbiomes but with an unusually high representation of bacteria from the family Phyllobacteriaceae.

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“…It is well understood that animals with highly specialized diets also are likely to have highly specialized intestinal microbial communities ( Higgins et al, 2011 ; Kohl et al, 2014 ; Alfano et al, 2015 ; Kohl, Stengel & Denise Dearing, 2016 ). Disturbances of a specialized microbial community, such as the introduction of antibiotics, can have profound effects on the host’s health ( Kohl & Denise Dearing, 2016 ; Brice et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Isolation and sequence-based characterization of a koala symbiont: Lonepinella koalarum

Dahlhausen

Jospin

Coil

et al. 2020

PeerJ

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Koalas (Phascolarctos cinereus) are highly specialized herbivorous marsupials that feed almost exclusively on Eucalyptus leaves, which are known to contain varying concentrations of many different toxic chemical compounds. The literature suggests that Lonepinella koalarum, a bacterium in the Pasteurellaceae family, can break down some of these toxic chemical compounds. Furthermore, in a previous study, we identified L. koalarum as the most predictive taxon of koala survival during antibiotic treatment. Therefore, we believe that this bacterium may be important for koala health. Here, we isolated a strain of L. koalarum from a healthy koala female and sequenced its genome using a combination of short-read and long-read sequencing. We placed the genome assembly into a phylogenetic tree based on 120 genome markers using the Genome Taxonomy Database (GTDB), which currently does not include any L. koalarum assemblies. Our genome assembly fell in the middle of a group of Haemophilus, Pasteurella and Basfia species. According to average nucleotide identity and a 16S rRNA gene tree, the closest relative of our isolate is L. koalarum strain Y17189. Then, we annotated the gene sequences and compared them to 55 closely related, publicly available genomes. Several genes that are known to be involved in carbohydrate metabolism could exclusively be found in L. koalarum relative to the other taxa in the pangenome, including glycoside hydrolase families GH2, GH31, GH32, GH43 and GH77. Among the predicted genes of L. koalarum were 79 candidates putatively involved in the degradation of plant secondary metabolites. Additionally, several genes coding for amino acid variants were found that had been shown to confer antibiotic resistance in other bacterial species against pulvomycin, beta-lactam antibiotics and the antibiotic efflux pump KpnH. In summary, this genetic characterization allows us to build hypotheses to explore the potentially beneficial role that L. koalarum might play in the koala intestinal microbiome. Characterizing and understanding beneficial symbionts at the whole genome level is important for the development of anti- and probiotic treatments for koalas, a highly threatened species due to habitat loss, wildfires, and high prevalence of Chlamydia infections.

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Dietary specialization and Eucalyptus species preferences in Queensland koalas (Phascolarctos cinereus)

Cited by 8 publications

References 19 publications

Quantification and Localization of Formylated Phloroglucinol Compounds (FPCs) in Eucalyptus Species

Quantification and Localization of Formylated Phloroglucinol Compounds (FPCs) in Eucalyptus Species

Variation in koala microbiomes within and between individuals: effect of body region and captivity status

Isolation and sequence-based characterization of a koala symbiont: Lonepinella koalarum

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