The Royal Botanic Gardens and Domain Trust

Sydney, Australia

The Royal Botanic Gardens and Domain Trust

Sydney, Australia
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Hamilton K.N.,The Royal Botanic Gardens and Domain Trust | Offord C.A.,The Royal Botanic Gardens and Domain Trust | Cuneo P.,The Royal Botanic Gardens and Domain Trust | Deseo M.A.,Southern Cross University of Australia
Plant Species Biology | Year: 2013

Seed characteristics were measured in 71 Eastern Australian rainforest species representing 30 families. Sensitivity to desiccation to low moisture contents (<10%) occurred in 42% of species. We estimate, based on findings from 100 species from this present study and previously published reports, that 49% of Eastern Australian rainforest species have non-orthodox seeds. Germination level and time to 50% germination were not significantly different between desiccation sensitive (DS) and desiccation tolerant (DT) seeds. The estimation of seed desiccation sensitivity based on predictors is an important tool underpinning ex situ conservation efforts. Seed characteristics differed significantly between DS and DT seeds; that is, DS seeds had: (i) larger fruits (19949mg vs 8322mg); (ii) larger seeds (1663mg vs 202mg); (iii) higher seed moisture contents (49.7% vs 35.5% fresh weight); (iv) lower oil content (7.3% vs 24.8% yield); and (v) less investment in seed coats (0.19 vs 0.48 seed coat ratio). Only 25% of DS seeded species had oily seeds compared with 87% of DT seeded species. Most green embryos were DS. Seed coat ratio was the best predictor of seed DS (80% correctly predicted). Seed moisture content at maturity was also related to germination time. Mean seed size was correlated (-0.657, P=0.01) with mean seed oil content in 46 species. Further research on seed storage physiology of possible oily and/or DS seeded species is crucial to ensure future long-term security of this biodiversity, particularly for species currently threatened in situ and/or of socioeconomic importance in Eastern Australian rainforests. © 2012 The Society for the Study of Species Biology.


Jordan G.J.,University of Tasmania | Brodribb T.J.,University of Tasmania | Blackman C.J.,University of Tasmania | Blackman C.J.,Macquarie University | Weston P.H.,The Royal Botanic Gardens and Domain Trust
American Journal of Botany | Year: 2013

Premise of study: The mechanisms by which plants tolerate water defi cit are only just becoming clear. One key factor in drought tolerance is the ability to maintain the capacity to conduct water through the leaves in conditions of water stress. Recent work has shown that a simple feature of the leaf xylem cells, the cube of the thickness of cell walls divided by the lumen width (t/b) 3, is strongly correlated with this ability. • Methods: Using ecologically, phylogenetically, and anatomically diverse members of Proteaceae, we tested the relationships between (t/b) 3 and climate, leaf mass per unit area, leaf area, and vein density. To test relationships at high phylogenetic levels (mostly genus), we used phylogenetic and nonphylogenetic single and multiple regressions based on data from 50 species. We also used 14 within-genus species pairs to test for relationships at lower phylogenetic levels. • Key results: All analyses revealed that climate, especially mean annual precipitation, was the best predictor of (t/b) 3. The variation in (t/b) 3 was driven by variation in both lumen diameter and wall thickness, implying active control of these dimensions. Total vein density was weakly related to (t/b) 3 but unrelated to either leaf area or climate. Conclusions: We conclude that xylem reinforcement is a fundamental adaptation for water stress tolerance and, among evergreen woody plants, drives a strong association between rainfall and xylem anatomy. The strong association between (t/b) 3 and climate cannot be explained by autocorrelation with other aspects of leaf form and anatomy that vary along precipitation gradients. © 2013 Botanical Society of America.


Pinaria A.G.,Sam Ratulangi University | Laurence M.H.,The Royal Botanic Gardens and Domain Trust | Burgess L.W.,University of Sydney | Liew E.C.Y.,The Royal Botanic Gardens and Domain Trust
Plant Pathology | Year: 2015

Vanilla stem rot, caused by Fusarium oxysporum f. sp. vanillae (Fov), is the main constraint to increasing vanilla production in the major vanilla-producing countries, including Indonesia. The current study investigated the origin of Fov in Indonesia using a multigene phylogenetic approach. Nineteen Fov isolates were selected to represent Indonesia, the Comoros, Mexico and Réunion Island. The translation elongation factor 1 alpha gene and the mitochondrial small subunit ribosomal RNA gene phylogenies resolved the Fov isolates into three distinct clades in both phylogenetic species of the F. oxysporum species complex, indicating a polyphyletic pattern of evolution. In addition, Fov isolates from Indonesia were also polyphyletic. These results suggest that the vanilla stem rot pathogen in Indonesia has a complex origin. The implications for disease management are discussed. © 2015 British Society for Plant Pathology.


Laurence M.H.,University of Sydney | Burgess L.W.,University of Sydney | Summerell B.A.,The Royal Botanic Gardens and Domain Trust | Liew E.C.Y.,The Royal Botanic Gardens and Domain Trust
Fungal Biology | Year: 2012

The Fusarium oxysporum species complex (FOSC) is a ubiquitous ascomycetous group that includes both pathogenic and non-pathogenic strains, the former being responsible for disease in over 100 cultivated plant species. Previous phylogenetic studies have uncovered at least four major clades within the FOSC, with Clade 1 hypothesised as being ancestral. However, the origin of these clades and pathogenic strains is poorly understood. Due to an emphasis on agricultural isolates in previous studies, the underlying diversity of this species complex in non-cultivated soils is largely unknown. To address this imbalance an extensive survey of isolates associated with native vegetation geographically isolated from cultivation throughout the Australian continent was conducted. A multi-gene phylogenetic analysis of the translation elongation factor (EF-1α) and the mitochondrial small subunit (mtSSU) rDNA loci did not recover any novel clades. However, the Australian isolates had high levels of intra-Clade diversity based on EF-1α sequence type (ST) comparison with a global dataset. The ST diversity was not equally distributed across the four clades, with the majority of novel STs recovered from Clade 1. Implications on the origin of the FOSC are discussed. © 2011 British Mycological Society.


Laurence M.H.,University of Sydney | Summerell B.A.,The Royal Botanic Gardens and Domain Trust | Burgess L.W.,University of Sydney | Liew E.C.Y.,The Royal Botanic Gardens and Domain Trust
Fungal Biology | Year: 2014

Fusarium oxysporum is an important plant and human pathogenic ascomycetous group, with near ubiquity in agricultural and non-cultivated ecosystems. Phylogenetic evidence suggests that F. oxysporum is a complex of multiple morphologically cryptic species. Species boundaries and limits of genetic exchange within this complex are poorly defined, largely due to the absence of a sexual state and the paucity of morphological characters. This study determined species boundaries within the F. oxysporum species complex using Genealogical Concordance Phylogenetic Species Recognition (GCPSR) with eight protein coding loci. GCPSR criteria were used firstly to identify independent evolutionary lineages (IEL), which were subsequently collapsed into phylogenetic species. Seventeen IELs were initially identified resulting in the recognition of two phylogenetic species. Further evidence supporting this delineation is discussed. © 2014 The British Mycological Society.


Puno V.I.,University of Sydney | Laurence M.H.,The Royal Botanic Gardens and Domain Trust | Guest D.I.,University of Sydney | Liew E.C.Y.,The Royal Botanic Gardens and Domain Trust
Australasian Plant Pathology | Year: 2015

Phytophthora multivora, a recently described species recovered from declining natural ecosystems in Western Australia, was detected in the natural site of the rare and endangered Wollemi pine in New South Wales. The Phytophthora species was identified based on morphology and sequence analysis of the rDNA ITS and mitochondrial DNA cox1 regions. A pathogenicity trial to test the susceptibility of Wollemi pine to P. multivora resulted in symptoms equal in extent to those caused by P. cinnamomi, a known pathogen of Wollemi pine. Post-trial dry root weight analysis of P. multivora and P. cinnamomi inoculated plants revealed no significant difference between species, as both significantly reduced root mass compared to uninoculated plants. P. multivora was shown to be a pathogen of the Wollemi pine, and the implications on protecting this endangered species in the wild are discussed. © 2015, Australasian Plant Pathology Society Inc.


Laurence M.H.,The Royal Botanic Gardens and Domain Trust | Walsh J.L.,University of Sydney | Shuttleworth L.A.,The Royal Botanic Gardens and Domain Trust | Robinson D.M.,The Royal Botanic Gardens and Domain Trust | And 7 more authors.
Fungal Diversity | Year: 2016

Six new species of Fusarium associated with soil and plant hosts from ecosystems of minimal anthropogenic disturbance in Australia are described. Fusarium coicis from Coix gasteenii, F. goolgardi from Xanthorrhoea glauca, F. mundagurra from soil and Mangifera indica, F. newnesense from soil, F. tjaetaba from Sorghum interjectum and F. tjaynera from soil, Triodia microstachya, Sorghum interjectum and Sorghum intrans. Morphology and phylogenetic analysis of EF-1α, RPB1 and RPB2 sequence data were used to delineate species boundaries. The new species were phylogenetically distributed in the Fusarium sambucinum, F. fujikuroi, and F. chlamydosporum species complexes, and two novel species complexes. These six new species have particular phylogeographic significance as not only do they provide further insight into the geographic patterns of Fusarium evolution but also challenge current phylogeographic hypotheses. © 2015, School of Science.


Laurence M.H.,The Royal Botanic Gardens and Domain Trust | Summerell B.A.,The Royal Botanic Gardens and Domain Trust | Liew E.C.Y.,The Royal Botanic Gardens and Domain Trust
Plant Pathology | Year: 2015

Fusarium wilt is a serious disease of the date palm Phoenix canariensis, caused by Fusarium oxysporum f. sp. canariensis (Foc). A previous study that characterized and compared the genetic diversity of the Australian Foc population with international strains suggested that the Australian population may have had an independent evolutionary origin. The current study compared the species phylogeny of the Australian and international populations and determined that Foc is not monophyletic, separating into three supported lineages across the two phylogenetic species of the Fusarium oxysporum species complex. This confirms an independent evolutionary origin for Foc in Australia. However, phylogenetic analysis of the putative pathogenicity genes Secreted In Xylem (SIX) did not reveal any separation of the Australian and international Foc strains. Furthermore, there was very low SIX sequence diversity within Foc. Horizontal gene transfer is argued to be the most parsimonious explanation for the incongruence between the species and SIX gene phylogenies. © 2015 British Society for Plant Pathology.


Rocha L.O.,The Royal Botanic Gardens and Domain Trust | Laurence M.H.,The Royal Botanic Gardens and Domain Trust | Proctor R.H.,National United University | McCormick S.P.,National United University | And 2 more authors.
Toxins | Year: 2015

Fusarium goolgardi, isolated from the grass tree Xanthorrhoea glauca in natural ecosystems of Australia, is closely related to fusaria that produce a subgroup of trichothecene (type A) mycotoxins that lack a carbonyl group at carbon atom 8 (C-8). Mass spectrometric analysis revealed that F. goolgardi isolates produce type A trichothecenes, but exhibited one of two chemotypes. Some isolates (50%) produced multiple type A trichothecenes, including 4,15-diacetoxyscirpenol (DAS), neosolaniol (NEO), 8-acetylneosolaniol (Ac-NEO) and T-2 toxin (DAS-NEO-T2 chemotype). Other isolates (50%) produced only DAS (DAS chemotype). In the phylogenies inferred from DNA sequences of genes encoding the RNA polymerase II largest (RPB1) and second largest (RPB2) subunits as well as the trichothecene biosynthetic genes (TRI), F. goolgardi isolates were resolved as a monophyletic clade, distinct from other type A trichothecene-producing species. However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus. Phylogenies based on different TRI loci resolved isolates with different chemotypes into distinct clades, even though only the TRI1-TRI16 locus is responsible for structural variation at C-8. Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation. © 2015 by the authors; licensee MDPI, Basel, Switzerland.


PubMed | The Royal Botanic Gardens and Domain Trust and National United University
Type: Journal Article | Journal: Toxins | Year: 2015

Fusarium goolgardi, isolated from the grass tree Xanthorrhoea glauca in natural ecosystems of Australia, is closely related to fusaria that produce a subgroup of trichothecene (type A) mycotoxins that lack a carbonyl group at carbon atom 8 (C-8). Mass spectrometric analysis revealed that F. goolgardi isolates produce type A trichothecenes, but exhibited one of two chemotypes. Some isolates (50%) produced multiple type A trichothecenes, including 4,15-diacetoxyscirpenol (DAS), neosolaniol (NEO), 8-acetylneosolaniol (Ac-NEO) and T-2 toxin (DAS-NEO-T2 chemotype). Other isolates (50%) produced only DAS (DAS chemotype). In the phylogenies inferred from DNA sequences of genes encoding the RNA polymerase II largest (RPB1) and second largest (RPB2) subunits as well as the trichothecene biosynthetic genes (TRI), F. goolgardi isolates were resolved as a monophyletic clade, distinct from other type A trichothecene-producing species. However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus. Phylogenies based on different TRI loci resolved isolates with different chemotypes into distinct clades, even though only the TRI1-TRI16 locus is responsible for structural variation at C-8. Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation.

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