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Ni-Ni-Win,Kobe University | Hanyuda T.,Kobe University | Arai S.,Marine Algal Research Co. | Uchimura M.,Port and Airport Research Institute | And 6 more authors.
Journal of Phycology | Year: 2011

A taxonomic study of the genus Padina from Japan, Southeast Asia, and Hawaii based on morphology and gene sequence data (rbcL and cox3) resulted in the recognition of four new species, that is, Padina macrophylla and Padina ishigakiensis from Ryukyu Islands, Japan; Padina maroensis from Hawaii; and Padina usoehtunii from Myanmar and Thailand. All species are bistratose and morphologically different from one another as well as from any known taxa by a combination of characters relating to degree of calcification; the structure, position, and arrangement of hairlines (HLs) and reproductive sori; and the presence or absence of rhizoid-like groups of hairs and an indusium. Molecular phylogenetic analyses demonstrated a close relationship between P. ishigakiensis, P. macrophylla, P. maroensis, and Padina australis Hauck. The position of P. usoehtunii, however, was not fully resolved, being either sister to a clade comprising the other three new species and P. australis in the rbcL tree or more closely related to a clade comprising several other recently described species in the cox3 tree. The finding of the four new species demonstrates high species diversity particularly in southern Japan. The following characters were first recognized here to be useful for species delimitation: the presence or absence of small rhizoid-like groups of hairs on the thallus surface, structure and arrangement of HLs on both surfaces either alternate or irregular, and arrangement of the alternating HLs between both surfaces in equal or unequal distance. The evolutionary trajectory of these and six other morphological characters used in species delineation was traced on the phylogenetic tree. © 2011 Phycological Society of America.

Truong N.V.,Hue University | Liew E.C.Y.,Royal Botanic Gardens Sydney | Burgess L.W.,University of Sydney
Fungal Biology | Year: 2010

Phytophthora foot rot of black pepper caused by Phytophthora capsici is a major disease of black pepper (Piper nigrum) throughout Vietnam. To understand the population structure of P. capsici, a large collection of P. capsici isolates from black pepper was studied on the basis of mating type, random amplified microsatellites (RAMS) and repetitive extragenic palindromic (REP) fingerprinting. Two mating types A1 and A2 were detected in four provinces in two climatic regions, with A1:A2 ratios ranging from 1:3 to 1:5. In several instances A1 and A2 mating types were found to co-exist in the same farm or black pepper pole, suggesting the potential for sexual reproduction of P. capsici in the field in Vietnam although its contribution to disease epidemics is uncertain. RAMS and REP DNA fingerprinting analysis of 118 isolates of P. capsici from black pepper showed that the population was genetically more diverse where two mating types were found, although the overall genetic diversity was low with most of the isolates belonging to one clonal group. The implication of these findings is discussed. The low diversity among isolates suggests that the P. capsici population may have originated from a single source. There was no genetic differentiation of isolates from different climatic regions. In addition to the large clonal group, several isolates with unique RAMS/REP phenotypes were also detected. Most of these unique phenotypes belonged to the minority A1 mating type. This may have significant implications for a gradual increase in overall genetic diversity. © 2009 The British Mycological Society.

Ni-Ni-Win N.,Kobe University | Sun Z.-M.,Kobe University | Hanyuda T.,Kobe University | Kurihara A.,Kobe University | And 5 more authors.
Australian Systematic Botany | Year: 2013

Molecular phylogenetic analyses based on plastid-encoded rbcL and mitochondrial cox3 gene sequences, in combination with morphological observations, revealed the existence of the following four bistratose Padina species previously unreported from Australian coasts: Padina calcarea Ni-Ni-Win, S.G.A.Draisma, W.F.Prud'homme van Reine & H.Kawai, characterised by its bright yellow-orange inferior thallus surface and chalky white, heavily calcified superior surface, and the presence of hairlines only on the inferior surface; P. macrophylla Ni-Ni-Win, M.Uchimura & H.Kawai, characterised by a moderately calcified thallus with broad, depressed hairlines on the inferior surface and narrow, not depressed hairlines on the superior surface, those hairlines that are largely spaced on each surface; P. moffittiana I.A.Abbott & Huisman, characterised by lightly calcified thalli with narrow, slightly depressed hairlines that are distributed in alternate sequence between the two surfaces at unequal distances, and broad reproductive sori in one or two rows in the fertile zone; and P. okinawaensis Ni-Ni-Win, S.Arai, M.Uchimura & H.Kawai, characterised by heavily calcified thalli, except at the hairlines, which form an alternation of uncalcified furrows and calcified glabrous zones on the inferior surface. With the addition of these four species, 13 Padina species are known from Australia. © CSIRO 2014.

Huisman J.M.,Murdoch University | Millar J.K.,Royal Botanic Gardens Sydney
Phycologia | Year: 2015

Huisman & Millar reply to the criticisms of their commentary regarding a paper describing range shifts in Australian seaweeds based on historical herbarium records. © 2015 International Phycological Society.

Truong N.V.,Hue University | Burgess L.W.,University of Sydney | Liew E.C.Y.,Royal Botanic Gardens Sydney
Archives of Phytopathology and Plant Protection | Year: 2012

Phytophthora foot rot of black pepper caused by Phytophthora capsici is a major disease of black pepper throughout production areas in Vietnam. The disease causes collar, foot and tap root rots and eventual death of the infected vine. Potassium phosphonate was evaluated for the control of this disease in greenhouse and field trials. In greenhouse trials three-month-old vines treated with phosphonate by soil drenching (10-20 g a.i./l) and then inoculated with P. capsici mycelium (2% v/v soil) had significantly less foot rot compared to vines grown in non-treated soil. In field trials mature vines were treated with phosphonate at 50-100 g a.i/pole soil drenching or 10 g a.i./l by root infusion. After 10 days root, stem and leaf specimens were removed for bioassay by inoculation with 5 ml of P. capsici zoospores suspension (10 6-10 8 spores/ml). Soil drenching with phosphonate inhibited the colonisation of pathogen on excised leaf, stem and root tissues, significantly more than phosphonate root infusion. Our study provides further evidence supporting the efficacy of potassium phosphonate in the management of black pepper foot rot caused by P. capsici. The excised leaf and stem bioassay used in this study is a rapid and useful technique for testing the efficacy of systemic fungicides in controlling this disease. © 2012 Copyright Taylor and Francis Group, LLC.

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