Metrosideros polymorpha var. glaberrima
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ABSTRACT:
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| Other | ||||
| DRR050360_1.fastq.gz | Fastqsanger.gz | |||
| DRR050360_2.fastq.gz | Fastqsanger.gz | |||
| DRR050361_1.fastq.gz | Fastqsanger.gz | |||
| DRR050361_2.fastq.gz | Fastqsanger.gz |
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Project description:Although trees comprise a primary component of terrestrial species richness, the drivers and temporal scale of divergence in trees remain poorly understood. We examined the landscape-dominant tree, Metrosideros polymorpha, for variation at nine microsatellite loci across 23 populations on young Hawai'i Island, sampling each of the island's five varieties throughout its full geographic range. For four varieties, principal coordinate analysis revealed strong clustering of populations by variety across the 10 430 km(2) island, indicating partitioning of the species into multiple evolutionarily significant units. The single island-endemic form, riparian var. newellii, showed especially strong differentiation from other varieties despite occurring in sympatry with other varieties and likely evolved from a bog form on the oldest volcano, Kohala, within the past 500 000 years. Along with comparable riparian forms on other Pacific Islands, var. newellii appears to represent parallel incipient ecological speciation within Metrosideros. Greater genetic distance among the more common varieties on the oldest volcano and an inverse relationship between allelic diversity and substrate age appear consistent with colonization of Hawai'i Island by older, partially diverged varieties followed by increased hybridization among varieties on younger volcanoes. This study demonstrates that broad population-level sampling is required to uncover patterns of diversification within a ubiquitous and long-lived tree species. Hawaiian Metrosideros appears to be a case of incipient radiation in trees and thus should be useful for studies of divergence and the evolution of reproductive isolating barriers at the early stages of speciation.
| S-EPMC4181069 | biostudies-literature
Project description:BACKGROUND:Isoprene is a five-carbon chemical that is an important starting material for the synthesis of rubber, elastomers, and medicines. Although many plants produce huge amounts of isoprene, it is very difficult to obtain isoprene directly from plants because of its high volatility and increasing environmental regulations. Over the last decade, microorganisms have emerged as a promising alternative host for efficient and sustainable bioisoprene production. Isoprene synthase (IspS) has received much attention for the conversion of isoprene from dimethylallyl diphosphate (DMAPP). Herein, we isolated a highly expressible novel IspS gene from Metrosideros polymorpha (MpIspS), which was cloned and expressed in Escherichia coli, using a plant cDNA library and characterized its molecular and biochemical properties. RESULTS:The signal sequence deleted MpIspS was cloned and expressed in E. coli as a 65-kDa monomer. The maximal activity of the purified MpIspS was observed at pH 6.0 and 55 °C in the presence of 5 mM Mn2+. The Km, kcat, and kcat/Km for DMAPP as a substrate were 8.11 mM, 21 min-?1, and 2.59 mM-?1 min-?1, respectively. MpIspS was expressed along with the exogenous mevalonate pathway to produce isoprene in E. coli. The engineered cells produced isoprene concentrations of up to 23.3 mg/L using glycerol as the main carbon source. CONCLUSION:MpIspS was expressed in large amounts in E. coli, which led to increased enzymatic activity and resulted in isoprene production in vivo. These results demonstrate a new IspS enzyme that is useful as a key biocatalyst for bioisoprene production in engineered microbes.
| S-EPMC6003189 | biostudies-literature
Project description:BackgroundRecent studies show that galling Hymenoptera and Diptera are able to synthesize the plant hormone indole-3-acetic acid (auxin) from tryptophan and that plant response to insect-produced auxin is implicated in gall formation. We examined the leaf transcriptome of galled and ungalled leaves of individuals of the Hawaiian endemic plant Metrosideros polymorpha (Myrtaceae) subject to infestation by psyllid (Hemiptera) gall-makers in the genus Trioza (Triozidae).ResultsTranscript libraries were sequenced using Illumina technology and the reads assembled de novo into contigs. Functional identification of contigs followed a two-step procedure, first identifying contigs by comparison to the completely sequenced genome of the related Eucalyptus, followed by identifying the equivalent Arabidopsis gene using a pre-computed mapping between Eucalyptus and Arabidopsis genes. This allowed us to use the rich functional annotation of the Arabidopsis genome to assess the transcriptional landscape of galling in Metrosideros. Comparing galled and ungalled leaves, we find a highly significant enrichment of expressed genes with a gene ontology (GO) annotation to auxin response in the former. One gene consistently expressed in all galled trees examined but not detected in any libraries from ungalled leaves was the Metrosideros version of SMALL AUXIN UPREGULATED (SAUR) 67 which appears to be a marker for leaf-galling in Metrosideros.ConclusionsWe conclude that an auxin response is involved in galling by Metrosideros psyllids. The possibility should therefore be considered that psyllids (like other insects examined) are able to synthesize auxin.
| S-EPMC4647832 | biostudies-literature
Project description:The native 'ōhi'a lehua (Metrosideros polymorpha) has cultural, biological and ecological significance to Hawai'i, but it is seriously threatened by a disease commonly referred to as rapid 'ōhi'a death (ROD). Preliminary investigations showed that a Ceratocystis species similar to C. fimbriata s.lat. was the cause of the disease. In this study, we used a combination of the phylogenetic, morphological and biological species concepts, as well as pathogenicity tests and microsatellite analyses, to characterise isolates collected from diseased 'ōhi'a trees across Hawai'i Island. Two distinct lineages, representing new species of Ceratocystis, were evident based on multigene phylogenetic analyses. These are described here as C. lukuohia and C. huliohia. Ceratocystis lukuohia forms part of the Latin American clade (LAC) and was most closely associated with isolates from Syngonium and Xanthosoma from the Caribbean and elsewhere, including Hawai'i, and C. platani, which is native to eastern USA. Ceratocystis huliohia resides in the Asian-Australian clade (AAC) and is most closely related to C. uchidae, C. changhui and C. cercfabiensis, which are thought to be native to Asia. Morphology and interfertility tests support the delineation of these two new species and pathogenicity tests show that both species are aggressive pathogens on seedlings of M. polymorpha. Characterisation of isolates using microsatellite markers suggest that both species are clonal and likely represent recently-introduced strains. Intensive research is underway to develop rapid screening protocols for early detection of the pathogens and management strategies in an attempt to prevent the spread of the pathogens to the other islands of Hawai'i, which are currently disease free.
| S-EPMC6146641 | biostudies-literature
Project description:Background and aimsPlants inhabiting arid environments tend to have leaf trichomes, but their adaptive significance remains unclear. Leaf trichomes are known to play a role in plant defence against herbivores, including gall makers. Because gall formation can increase water loss partly through increased surface area, we tested the novel hypothesis that leaf trichomes could contribute to avoiding extra water stress by impeding gall formation, which would have adaptive advantages in arid environments.MethodsWe focused on Metrosideros polymorpha, an endemic tree species in the Hawaiian Islands, whose leaves often suffer from galls formed by specialist insects, Hawaiian psyllids (Pariaconus spp.). There is large variation in the amount of leaf trichomes (0-40 % of leaf mass) in M. polymorpha. Three gall types are found on the island of Hawaii: the largest is the 'cone' type, followed by 'flat' and 'pit' types. We conducted laboratory experiments to quantify the extent to which gall formation is associated with leaf water relations. We also conducted a field census of 1779 individuals from 48 populations across the entire range of habitats of M. polymorpha on the island of Hawaii to evaluate associations between gall formation (presence and abundance) and the amount of leaf trichomes.Key resultsOur laboratory experiment showed that leaf minimum conductance was significantly higher in leaves with a greater number of cone- or flat-type galls but not pit-type galls. Our field census suggested that the amount of trichomes was negatively associated with probabilities of the presence of cone- or flat-type galls but not pit-type galls, irrespective of environmental factors.ConclusionOur results suggest that leaf trichomes in M. polymorpha can contribute to the avoidance of extra water stress through interactions with some gall-making species, and potentially increase the fitness of plants under arid conditions.
| S-EPMC7061171 | biostudies-literature
Project description:Intraspecific hybrid zones involving long-lived woody species are rare and can provide insights into the genetic basis of early-diverging traits in speciation. Within the landscape-dominant Hawaiian tree, Metrosideros polymorpha, are morphologically distinct successional varieties, incana and glaberrima, that dominate new and old lava flows, respectively, below 1200 me on volcanically active Hawai'i Island, with var. glaberrima also extending to higher elevations and bogs. Here, we use morphological measurements on 86 adult trees to document the presence of an incana-glaberrima hybrid zone on the 1855 Mauna Loa lava flow on east Hawai'i Island and parent-offspring analysis of 1311 greenhouse seedlings from 71 crosses involving 72 adults to estimate heritabilities and genetic correlations among vegetative traits. Both the variation in adult leaf pubescence at the site and the consistency between adult and offspring phenotypes suggest the presence of two hybrid classes, F1s and var. incana backcrosses, as would be expected on a relatively young lava flow. Nine nuclear microsatellite loci failed to distinguish parental and hybrid genotypes. All four leaf traits examined showed an additive genetic basis with moderate to strong heritabilities, and genetic correlations were stronger for the more range-restricted var. incana. The differences between varieties in trait values, heritabilities and genetic correlations, coupled with high genetic variation within but low genetic variation between varieties, are consistent with a multi-million-year history of alternating periods of disruptive selection in contrasting environments and admixture in ephemeral hybrid zones. Finally, the contrasting genetic architectures suggest different evolutionary trajectories of leaf traits in these forms.
| S-EPMC4981685 | biostudies-literature
Project description:Accurate feature annotation as well as assembly contiguity are important requisites of a modern genome assembly. They allow large-scale comparison of genomes across and within species and identification of polymorphisms, leading evolutionary and functional studies. We report an updated genome resource for Metrosideros polymorpha, the most dominant tree species in the Hawaiian native forests and a unique example of rapid and remarkable ecological diversification of woody species. Ninety-one percent of the bases in the sequence assembly (304 Mb) were organized into 11 pseudo-molecules, which would represent the chromosome structure of the species assuming the synteny to a close relative Eucalyptus Our complementary approach using manual annotation and automated pipelines identified 11.30% of the assembly to be transposable elements, in contrast to 4.1% in previous automated annotation. By increasing transcript and protein sequence data, we predicted 27,620 gene models with high concordance from the supplied evidence. We believe that this assembly, improved for contiguity, and annotation will be valuable for future evolutionary studies of M. polymorpha and closely related species, facilitating the isolation of specific genes and the investigation of genome-wide polymorphisms associated with ecological divergence.
| S-EPMC6829130 | biostudies-literature