Mycorrhizal status of <Emphasis Type="Italic">Eucalyptus</Emphasis> plantations in south China and implications for management

The aim of this study is to assess the mycorrhizal status of Eucalyptus plantations in south China and to determine the need for inoculation. In four provinces in south China, 155 plantations were sampled for sporocarps of ectomycorrhizal (ECM) fungi, spores of arbuscular mycorrhizal (AM) fungi, and mycorrhizas over 2 years. This study revealed a low above-ground diversity of ECM fungi consisting of 15 taxa fruiting beneath Eucalyptus plantations. The most common ECM genera were Scleroderma and Pisolithus, but they were infrequent. A total of 21 AM fungi, mostly Glomus species, were recognized from spores collected from eucalypt plantations. Four Glomus species were frequently present in soils, but spore density and relative abundance of AM fungi were generally low. Eucalypt roots from all plantation sites were poorly colonized by either ECM fungi or AM fungi. A bioassay with E. urophylla as a bait host, using soils collected from 11 eucalypt plantations, confirmed low levels of inoculum of both ECM and AM fungi in field soil. This is the first integrated study on the mycorrhizal status of eucalypt plantations in China. Findings from this research can be used to encourage adoption of mycorrhizal technology by eucalypt nurseries in the region. The potential of using spores of compatible ECM fungi or collections for forest nurseries is discussed.     

Morphology and colonization preference of arbuscular mycorrhizal fungi in <Emphasis Type="Italic">Clethra barbinervis</Emphasis>, <Emphasis Type="Italic">Cucumis sativus</Emphasis>, and <Emphasis Type="Italic">Lycopersicon esculentum</Emphasis>

Clethra barbinervis (Ericales), Cucumis sativus, and Lycopersicon esculentum were grown in soils collected from six different vegetation sites (cedar, cypress, larch, red pine, bamboo grass, and Italian ryegrass), and morphology and colonization preference of arbuscular mycorrhizal (AM) fungi were investigated by microscopic observation and PCR detection. C. barbinervis consistently formed Paris-type AM throughout the sites. C. sativus formed both Arum- and Paris-type AM with high occurrence of Arum-type AM. L. esculentum also formed both Arum- and Paris-type AM but with high occurrence of Paris-type AM. AM diversity within the same plant species was different among the sites. Detected AM diversity from AM spores in different site soils did not consistently reflect AM fungal diversity seen in test plants. Detected families were different, depending on test plants grown even in the same soil. AM fungi belonging to Glomaceae were consistently detected from roots of all test plants throughout the sites. Almost all the families were detected from roots of C. barbinervis and L. esculentum. On the other hand, only two or three families of AM fungi (Archaeosporaceae and/or Paraglomaceae and Glomaceae) but not two other families (Acaulosporaceae and Gigasporaceae) were detected from roots of C. sativus, indicating strong colonization preference of AM fungi to C. sativus among test plants. This study demonstrated that host plant species strongly influenced the colonization preference of AM fungi in the roots.     

Differential effects of <Emphasis Type="Italic">Paenibacillus</Emphasis> spp. on cucumber mycorrhizas

The effects of 17 Paenibacillus strains on root colonization by Glomus intraradices or Glomus mosseae and plant growth parameters (shoot and root weight) of mycorrhizal cucumber plants were examined. The Paenibacillus strains were originally isolated from mycorrhizal (G. intraradices) and non-mycorrhizal cucumber rhizosphere and/or hyphosphere, except for strain EJP73, which originated from a Pinus sylvestris-Lactarius rufus ectomycorrhiza. Root colonization of cucumber plants by G. intraradices or G. mosseae was unaffected by all seven strains of Paenibacillus polymyxa, but was decreased or increased by four strains of Paenibacillus macerans and strain EJP73 of Paenibacillus sp. Overall, shoot dry weight of cucumber grown in symbioses with either G intraradices or G. mosseae was unaffected by inoculation with all of the Paenibacillus strains, except for strain MB02-429 of P. macerans, which increased the shoot dry weight in the cucumber-G. mosseae symbiosis. On the other hand, several Paenibacillus strains caused altered root growth. Three strains of P. polymyxa and four strains of P. macerans increased the root fresh weight of the cucumber–G. intraradices symbiosis, whereas three strains of P. polymyxa and one strain of P. macerans as well as Paenibacillus sp. EJP73, decreased the root fresh weight of the cucumber–G. mosseae symbiosis. In conclusion, our results show that bacteria from several species of Paenibacillus differentially affect cucumber mycorrhizas.     

Ultrastructure of spore development in <Emphasis Type="Italic">Scutellospora heterogama</Emphasis>

The ultrastructural detail of spore development in Scutellospora heterogama is described. Although the main ontogenetic events are similar to those described from light microscopy, the complexity of wall layering is greater when examined at an ultrastructural level. The basic concept of a rigid spore wall enclosing two inner, flexible walls still holds true, but there are additional zones within these three walls distinguishable using electron microscopy, including an inner layer that is involved in the formation of the germination shield. The spore wall has three layers rather than the two reported previously. An outer, thin ornamented layer and an inner, thicker layer are both derived from the hyphal wall and present at all stages of development. These layers differentiate into the outer spore layer visible at the light microscope level. A third inner layer unique to the spore develops during spore swelling and rapidly expands before contracting back to form the second wall layer visible by light microscopy. The two inner flexible walls also are more complex than light microscopy suggests. The close association with the inner flexible walls with germination shield formation consolidates the preferred use of the term ‘germinal walls’ for these structures. A thin electron-dense layer separates the two germinal walls and is the region in which the germination shield forms. The inner germinal wall develops at least two sub-layers, one of which has an appearance similar to that of the expanding layer of the outer spore wall. An electron-dense layer is formed on the inner surface of the inner germinal wall as the germination shield develops, and this forms the wall surrounding the germination shield as well as the germination tube. At maturity, the outer germinal wall develops a thin, striate layer within its substructure.     

The <Emphasis Type="Italic">Caenorhabditis</Emphasis><Emphasis Type="Italic">briggsae</Emphasis> genome contains active <Emphasis Type="Italic">CbmaT1</Emphasis> and <Emphasis Type="Italic">Tcb1</Emphasis> transposons

The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.     

Interactions between<Emphasis Type="Italic"> Trichoderma pseudokoningii</Emphasis> strains and the arbuscular mycorrhizal fungi<Emphasis Type="Italic"> Glomus mosseae</Emphasis> and<Emphasis Type="Italic"> Gigaspora rosea</Emphasis>

The interaction between Trichoderma pseudokoningii (Rifai) 511, 2212, 741A, 741B and 453 and the arbuscular mycorrhizal fungi Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe BEG12 and Gigaspora rosea Nicolson & Schenck BEG9 were studied in vitro and in greenhouse experiments. All T. pseudokoningii strains inhibited the germination of G. mosseae and Gi. rosea except the strain 453, which did not affect the germination of Gi. rosea. Soluble exudates and volatile substances produced by all T. pseudokoningii strains inhibited the spore germination of G. mosseae. The germination of Gi. rosea spores was inhibited by the soluble exudates produced by T. pseudokoningii 2212 and 511, whereas T. pseudokoningii 714A and 714B inhibited the germination of Gi. rosea spores by the production of volatile substances. The strains of T. pseudokoningii did not affect dry matter and percentage of root length colonization of soybean inoculated with G. mosseae, except T. pseudokoningii 2212, which inhibited both parameters. However, all T. pseudokoningii strains decreased the shoot dry matter and the percentage of AM root length colonization of soybean inoculated with Gi. rosea. The saprotrophic fungi tested seem to affect AM colonization of root by effects on the presymbiotic phase of the AM fungi. No influence of AM fungi on the number of CFUs of T. pseudokoningii was found. The effect of saprotrophic fungi on AM fungal development and function varied with the strain of the saprotrophic species tested.     

Tryptophan dimer produced by water-stressed bahia grass is an attractant for <Emphasis Type="Italic">Gigaspora margarita</Emphasis> and <Emphasis Type="Italic">Glomus caledonium</Emphasis>

We isolated and elucidated the structure of several stimulants for arbuscular mycorrhizal fungi (AMF) in water-stressed bahia grass roots. We could isolate some compounds that promoted the growth of Gigaspora margarita Becker and Hall and Glomus caledonium (Nicol. and Gerd.) Trappe and Gerd. In these compounds, tryptophan dimer (Trp–Trp) was elucidated the structure. Trp–Trp was abundantly produced in water-stressed bahia grass roots and exuded to the soil, although it was scarcely detected in non-stressed root exudates. Interestingly, this peptide strongly attracted the hyphae of Gi. margarita and G. caledonium and promoted their hyphal growth in vitro (1.8 × longer than the control). Tryptophan, however, had no effect on hyphal growth and attraction. Thus, Trp–Trp exuded from water-stressed roots would play an important role as a major signal for AMF. An erratum to this article can be found at     

<Emphasis Type="Italic">Drosophila</Emphasis><Emphasis Type="Italic">P</Emphasis> transposons of the urochordata <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Endophytic fungi from rhizomes of <Emphasis Type="Italic">Paris polyphylla</Emphasis> var. <Emphasis Type="Italic">yunnanensis</Emphasis>

About 63 fungal endophytic isolates were separated from rhizomes of Paris polyphylla var. yunnanensis, which is a traditional medicinal plant mainly distributed in China. The isolates were characterized and grouped based on the culture characteristics and the morphology of colony growth and conidia. Eleven representative ones were selected for further taxonomical identification. Five genera namely Fusarium, Gliocladiopsis, Gliomastix, Aspergillus and Cylindrocarpon were identified on the basis of their morphological characterizations. Of them, the most frequent genus was Fusarium (i.e. Ppf1, Ppf3 and Ppf14). Their ITS-rDNA sequences were compared with those available in the GeneBank databases to obtain the closest related species by BLAST analysis as well as to analyze their phylogenetic affiliation. The isolates were identified as Gliocladiopsis irregularis (Ppf2), Plectosphaerella cucumerina (Ppf4), Padospora sp. (Ppf6), Gliomastix murorum var. murorum (Ppf7), Aspergillus fumigatus (Ppf9), Pichia guilliermondii (Ppf10), Neonectria radicicola (anamorph: Cylindrocarpon) (Ppf12) and one uncultured mycorrhizal ascomycete (Ppf13) separately based on their morphological and molecular features. The molecular characters of the endophytic fungi were basically coincident with their morphology. The broad diversity and taxonomic spectrum were exhibited by the endophytic fungi from P. polyphylla var. yunnanensis.     

Floral development and systematic position of <Emphasis Type="Italic">Arillastrum</Emphasis>, <Emphasis Type="Italic">Allosyncarpia</Emphasis>, <Emphasis Type="Italic">Stockwellia</Emphasis> and <Emphasis Type="Italic">Eucalyptopsis</Emphasis> (Myrtaceae)

We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan.     

<Emphasis Type="Italic">Phuphanochloa,</Emphasis> a new bamboo genus (<Emphasis Type="Italic">Poaceae</Emphasis>: <Emphasis Type="Italic">Bambusoideae</Emphasis>) from Thailand

Summary  A new monotypic bamboo genus Phuphanochloa (Poaceae: Bambusoideae) from north-eastern Thailand is described, together with a new species, P. speciosa.     

Isolation and characterization of the <Emphasis Type="Italic">Larix gmelinii </Emphasis><Emphasis Type="Italic">ANGUSTIFOLIA</Emphasis> (<Emphasis Type="Italic">LgAN</Emphasis>) gene

ANGUSTIFOLIA (AN), a plant homolog of C-terminal binding protein, controls the polar elongation of leaf cells and the trichome-branching pattern in Arabidopsis thaliana. In the present study, degenerate PCR was used to isolate an ortholog of AN, referred to as LgAN, from larch (Larix gmelinii). The LgAN cDNA is predicted to encode a protein of 646 amino acids that shows striking sequence similarity to AN proteins from other plants. The predicted amino acid sequence has a conserved NAD-dependent 2-hydroxy acid dehydrogenase (D2-HDH) motif and a plant AN-specific LxCxE/D motif at its N-terminus, as well as a plant-specific long C-terminal region. The LgAN gene is a single-copy gene that is expressed in all larch tissues. Expression of the LgAN cDNA rescued the leaf width and trichome-branching pattern defects in the angustifolia-1 (an-1) mutant of Arabidopsis, showing that the LgAN gene has effects complementary to those of AN. These results suggest that the LgAN gene has the same function as the AN gene.     

In planta transformation of <Emphasis Type="Italic">Notocactus scopa</Emphasis> cv. <Emphasis Type="Italic">Soonjung</Emphasis> by <Emphasis Type="Italic">Agrobacterium </Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>

Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.     

Arbuscular mycorrhizal fungi colonize decomposing leaves of<Emphasis Type="Italic"> Myrica parvifolia</Emphasis>,<Emphasis Type="Italic"> M. pubescens</Emphasis> and<Emphasis Type="Italic"> Paepalanthus</Emphasis> sp.

Hyphae and vesicles of arbuscular mycorrhizal fungi (AMF) were found within the decomposing leaves of Myrica parvifolia, M. pubescens and Paepalanthus sp. at three montane sites in Colombia. Hyphae, vesicles, and arbuscule-like structures were also found within scale-like leaves of the rhizomes of Paepalanthus sp. The litter found in the vicinity of the roots was divided into three decomposition layers. The highest AMF colonization occurred in the most decomposed leaves, which were in close association with roots. In contrast, there were no differences in AMF colonization of roots present in the different decomposition layers. Colonization of decomposing leaves by AMF did not differ between the two closely related species M. parvifolia and M. pubescens, nor between two sites (Guatavita and Zipacón, Colombia) differing in soil fertility. Occurrence of vesicles in decomposing leaves was correlated with abundant AMF extraradical hyphae among the leaves. We propose that AMF enter decomposing leaves mechanically through vascular tissue. As a consequence, AMF are well positioned to obtain and efficiently recycle mineral nutrients released by decomposer microorganisms before their loss by leaching or immobilization in soil.     

<Emphasis Type="Italic">Funastrum rupicola</Emphasis> (<Emphasis Type="Italic">Apocynaceae:</Emphasis><Emphasis Type="Italic">Asclepiadoideae</Emphasis>), a new species from Bolivia

Summary   Funastrum rupicola Goyder, a new species of Apocynaceae: Asclepiadoideae from Bolivia, is described and illustrated. The conservation status of this species is assessed.     

Preparation,structural characterization and <Emphasis Type="Italic">in vitro</Emphasis> antitumor activity of <Emphasis Type="Italic">kappa</Emphasis>-carrageenan oligosaccharide fraction from <Emphasis Type="Italic">Kappaphycus striatum</Emphasis>

Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of kappa-carrageenan from Kappaphycus striatum to compare the antitumor activity with carrageenan polysaccharides. Oligosaccharide fractions were isolated by gel permeation chromatography and the structure of fraction 1 (F1) was studied by using negative-ion electrospray ionization-mass spectrometry (ESI-MS), and ¹H and ¹³C-NMR spectrometry. The in vitro antitumor effects in three human neoplastic cell lines (KB, BGC, and Hela) of polysaccharides and F1 were investigated. The bioassay results showed that F1 exhibited relatively higher antitumor activity against the three cancer cells than polysaccharides.