Phakopsora schreberae, sp. nov. (Uredinales) occurs onSchrebera swietenioides in India

A rust fungus was described fromSchrebera swietenioides (Oleaceae) collected in India. The fungus possessed densely paraphysate uredinia and subepidermal, crustose telia with irregulary 5–7-layered sessile teliospores. These morphologies are characteristic ofPhakopsora, although noPhakopsora species had been reported from the family Oleaceae. The fungus was concluded to be a new species and a name,Phakopsora schreberae, was proposed for the new species.     

A new species of <Emphasis Type="Italic">Puccinia</Emphasis> (Pucciniales,Basidiomycota) and new records of rust fungi from Panama

A new species of Puccinia with diorchidioid teliospores is described from Urochloa decumbens (Poaceae) in Panama. It differs from the other known species of Puccinia with diorchidioid teliospores by uredinia with paraphyses and urediniospores with 3–4 scattered germ pores. Twenty-one known species of rust fungi are cited for Panama for the first time. Alveolaria cordiae is a poorly known species which is reported, described and illustrated in detail for the first time on Cordia spinescens in Panama.     

Genetic dissection of fusiform rust and pitch canker disease traits in loblolly pine

Loblolly pine (Pinus taeda L.) exhibits genetic resistance to fusiform rust disease (incited by the biotrophic fungus, Cronartium quercuum f. sp. fusiforme) and pitch canker disease (incited by the necrotrophic fungus, Fusarium circinatum). In this study, a total of 14,015 loblolly pine cuttings from 1,065 clones were screened in controlled greenhouse conditions to identify phenotypes of clones, families, and parents that guide a genetic dissection of disease traits associated with pitch canker and fusiform rust. A total of 23,373 phenotypic data points were collected for lesion length (pitch canker) and gall score, gall length, and gall width (fusiform rust). We verified heritable fusiform rust and pitch canker traits and calculated parental, clonal, and full-sib family rankings for both diseases. Genetic correlations revealed that traits associated with fusiform rust are genetically distinct from one another, and that the genetic mechanisms underlying pitch canker and fusiform rust resistance are independent. The disease phenotyping described here is a critical step towards identifying specific loci and alleles associated with fusiform rust and pitch canker resistance.     

Fusarium proliferatum, an endophytic fungus from Dysoxylum binectariferum Hook.f, produces rohitukine, a chromane alkaloid possessing anti-cancer activity

Rohitukine is a chromane alkaloid possessing anti-inflammatory, anti-cancer and immuno-modulatory properties. The compound was first reported from Amoora rohituka (Meliaceae) and later from Dysoxylum binectariferum (Meliaceae) and Schumanniophyton problematicum (Rubiaceae). Flavopiridol, a semi-synthetic derivative of rohitukine is a potent CDK inhibitor and is currently in Phase III clinical trials. In this study, the isolation of an endophytic fungus, Fusarium proliferatum (MTCC 9690) from the inner bark tissue of Dysoxylum binectariferum Hook.f (Meliaceae) is reported. The endophytic fungus produces rohitukine when cultured in shake flasks containing potato dextrose broth. The yield of rohitukine was 186 μg/100 g dry mycelial weight, substantially lower than that produced by the host tissue. The compound from the fungus was authenticated by comparing the LC–HRMS and LC–HRMS/MS spectra with those of the reference standard and that produced by the host plant. Methanolic extract of the fungus was cytotoxic against HCT-116 and MCF-7 human cancer cell lines (IC₅₀ = 10 μg/ml for both cancer cell lines).     

Life cycle of <Emphasis Type="Italic">Uromyces appendiculatus</Emphasis> var. <Emphasis Type="Italic">azukicola</Emphasis> on <Emphasis Type="Italic">Vigna angularis</Emphasis>

Field observations and inoculation experiments revealed that Uromyces appendiculatus var. azukicola has an autoecious and macrocyclic life cycle and produces spermogonia, aecia, uredinia, and telia on Vigna angularis var. angularis and V. angularis var. nipponensis. From inoculation experiments, it was suggested that this rust fungus has different host relationships from other varieties. Morphological examinations revealed that the characteristics of urediniospores and teliospores are different among varieties, although aeciospores are morphologically similar to each other.Contribution no. 182, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Life cycle and life strategy features of Puccinia glechomatis (Uredinales) favorable for extending the natural range of distribution

The objective of this study was to find features in microcyclic rust fungi (Uredinales) on wild host plants favorable for extension of the natural range of distribution. Puccinia glechomatis, a leptosporic rust fungus and its herbal host Glechoma hederacea (Lamiaceae), both natives to Eurasia and introduced in North America, were used for this study. Although the host has been known from North America since the beginning of the nineteenth century, the rust fungus was first observed there only in recent years. Favorable features were identified by studying the life cycle of the rust, including nuclear conditions and seasonal characteristics as well as its spread in North America. The life cycle was studied macroscopically by inoculation experiments, by various light microscope techniques, and by scanning electron microscopy. The spread of the pathogen and its host were reconstructed by evaluating host plant herbarium specimens and databases, literature, and field study data. The studies on P. glechomatis show that, generally for microcyclic rust fungi, establishment and potential for spread are based on several favorable features of both the host (e.g., synanthropic occurence and dispersal, genetic stability, regeneration of vegetative plant parts) and the rust fungus (asexual reproduction/genetic stability, homothallism, propagation with host plant, formation of both leptospores and thick-walled teliospores).     

Genetic variation of <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> isolates forming fumonisin B<Subscript>1</Subscript> and moniliformin

Thirty single-spore isolates of a toxigenic fungus, Fusarium oxysporum, were isolated from asparagus spears and identified by species-specific polymerase chain reaction (PCR) and translation elongation factor 1-α (TEF) sequence analysis. In the examined sets of F. oxysporum isolates, the DNA sequences of mating type genes (MAT) were identified. The distribution of MAT idiomorph may suggest that MAT1-2 is a predominant mating type in the F. oxysporum population. F. oxysporum is mainly recognised as a producer of moniliformin—the highly toxic secondary metabolite. Moniliformin content was determined by high-performance liquid chromatography (HPLC) analysis in the range 0.05–1,007.47 μg g⁻¹ (mean 115.93 μg g⁻¹) but, also, fumonisin B₁ was detected, in the concentration range 0.01–0.91 μg g⁻¹ (mean 0.19 μg g⁻¹). There was no association between mating types and the mycotoxins biosynthesis level. Additionally, a significant intra-species genetic diversity was revealed and molecular markers associated with toxins biosynthesis were identified.     

Tissue culture of the alternate hosts of wheat,rye and oat rusts and their response to in vitro inoculation with the rust pathogens

Alternate host plants of cereal rust fungi are necessary for studying the rust sexual cycle and pathogenicity. These plants are usually difficult to propagate through cloning, while seed-propagated plants may have variable responses to the pathogen. To overcome these obstacles, tissue culture, under controlled and aseptic conditions, was utilized for clonal propagation and in vitro inoculation of the following species: Rhamnus palaestinus Boiss., the alternate host of oat (Avena spp.) crown rust (Puccinia coronata Corda); Thalictrum speciosissimum L., the alternate host of brown leaf rust of wheat (Puccinia recondita f. sp. tritici Eriks. & Henn.); and Lycopsis arvensis L., the alternate host of rye (Secala spp.) leaf rust (Puccinia recondita f. sp. recondita Rob. & Desm.). Shoot culture procedures for initial establishment and proliferation were developed for all three alternate host species. Shoot cultures were multiplied at rates ranging from 0.3 to 1.7 shoots/week. Successful infection following inoculation with teliospores of the corresponding rust fungi was obtained for R. palaestinus and T. speciosissimum but not for L. arvensis. The hardening and acclimatization efficiency of rooted T. speciosissimum and L. arvensis was of 80–90%. The propagation efficiency for R. palaestinus was not successful because of the low rate and poor quality of its rooting. It is concluded that the in vitro system might be used as an alternative method for inoculation and multiplication of alternate hosts of cereal rusts, although more experimentation is needed to define accurately the appropriate conditions for the proper infection response. This revised version was published online in June 2006 with corrections to the Cover Date.     

Asymptomatic systemic disease of Canada thistle (Cirsium arvense) caused by Puccinia punctiformis and changes in shoot density following inoculation

Canada thistle (Cirsium arvense) is one of the worst weeds in temperate areas of the world. A rust fungus, Puccinia punctiformis, was first proposed as a biological control agent for C. arvense in 1893. The rust causes systemic disease which ultimately kills C. arvense plants. In 2013 it was demonstrated in four countries, that inoculation of C. arvense rosettes in the fall with ground telia-bearing leaves can initiate epidemics of systemic rust disease with an average of 28% of inoculated rosettes producing a systemically diseased shoot the following spring. Other rosettes that emerged near inoculation points in spring were stunted and appeared diseased. To determine whether other rosettes were diseased, a chemiluminescence western slot blot test, applying polyclonal antibodies raised against P. punctiformis antigens, was developed to detect the fungus in roots. Rosettes were inoculated with telia-bearing leaves in the fall in Maryland, USA and Veroia, Greece. Roots of asymptomatic rosettes that emerged adjacent to inoculation points the following spring were tested for the presence of the fungus with the slot blot test. Rosettes that had diseased shoots were recorded. Based on the slot blot tests, 50–60% of the asymptomatic rosettes adjacent to inoculation points were positive for presence of the rust and likely to be systemically diseased. To demonstrate that systemic disease leads to C. arvense decline, C. arvense shoot densities were measured annually at 10 sites, in three countries, that had been inoculated with telia-bearing leaves in the fall between 2008 and 2012. Changes in C. arvense shoot densities over time were calculated. Average reductions in C. arvense density across the 10 sites were 43.1 ± 10.0% at 18 months after inoculation, 63.8 ± 8.0% at 30 months after inoculation, and 80.9 ± 16.5% at 42 months after inoculation, and 72.9 ± 27.2% at 54 months after inoculation; the 54 month reduction was, however, based on only two sites.     

Deep-sea parasitic nematodes of the genus <Emphasis Type="Italic">Trophomera</Emphasis> Rubtsov et Platonova, 1974 (Benthimermithidae) from the Equatorial Atlantic,with the descriptions of two new species

Nematode females of the genus Trophomera (Benthimermithidae) from the collection of the Smithsonian’s National Museum of Natural History (Washington, DC, USA) were examined. Nematodes were collected in different parts of the Western Atlantic (Hatteras Abyssal Plain, Brazil Basin, and Argentina Basin) from depths of 467–5,223 m. Two new species are described. Body length of T. americana sp. n. is 3,250–4,470 μm; posterior end conical with rounded tip; cephalic setae about 3–4 μm long; trophosome consisting of several longitudinal rows of large cells; ovaries reflected; mature eggs 35 μm in diameter. Body length of T. longiovaris sp. n. is 7,870–15,400 μm; posterior end conical with rounded tip; cephalic sensilla 7 μm long; mouth opening vestigial, present as very narrow apical pore; pharynx devoid of internal lumen and muscular envelope; midgut represents a trophosome without internal lumen; trophosomal cells arranged in 3–4 longitudinal rows; rectum and anus vestigial; female reproductive system didelphic, amphidelphic, very long, occupying about 0.8 total body length; ovaries telogonic, outstretched; oviducts very long, repeatedly folded across body axis; proximal parts of oviducts being than distal ones, uterus distinctly formed. New finds of two known species, T. arnauidi and T. marionensis, are also recorded and described.     

Pigmented Nanoflagellates Grazing on <Emphasis Type="Italic">Synechococcus</Emphasis>: Seasonal Variations and Effect of Flagellate Size in the Coastal Ecosystem of Subtropical Western Pacific

We investigated seasonal variation of grazing impact of the pigmented nanoflagellates (PNF) with different sizes upon Synechococcus in the subtropical western Pacific coastal waters using grazing experiments with fluorescently labeled Synechococcus (FLS). For total PNF, conspicuous seasonal variations of ingestion rates on Synechococcus were found, and a functional response was observed. To further investigate the impact of different size groups, we separated the PNF into four categories (<3, 3–5, 5–10, and >10 μm). Our results indicated that the smallest PNF (<3 μm PNF) did not ingest FLS and was considered autotrophic. PNF of 3–5 μm in size made up most of the PNF community; however, their ingestion on Synechococcus was too low (0.1–1.9 Syn PNF⁻¹ h⁻¹) to support their growth, and they had to depend on other prey or photosynthesis to survive. The ingestion rate of the 3–5 μm group exhibited no significant seasonal variation; by contrast, the ingestion rates of 5–10 and >10 μm PNFs showed significant seasonal variation. During the warm season, 3–5 μm PNF were responsible for the grazing of 12% of Synechococcus production, 5–10 μm PNF for 48%, and >10 μm PNF for 2%. Taken together, our results demonstrate that the PNF of 3–10 μm consumed most Synechococcus during the warm season and exhibited a significant functional response to the increase in prey concentration.     

三裂叶豚草锈病发生和流行规律的研究

通过田间调查与定点系统观察,结合沈阳地区的气象条件,对三裂叶豚草锈病在沈阳地区的发生和流行规律进行了研究。结果表明：三裂叶豚草锈病属于喜高温、高湿型病害;该病于6月初在沈阳地区开始发病,可持续至9月,以7～8月发病最重。人工接种试验结果表明：在30℃和相对湿度96．9％条件下接种锈菌冬孢子,4d后三裂叶豚草即可发病;冷冻保藏（-20℃）可打破冬孢子休眠,在沈阳地区冬孢子是第二年锈病发生的初侵染菌源。苍耳柄锈菌三裂叶豚草专化型对三裂叶豚草表现出了显著的致病性、致死性及专一性,证明是防治三裂叶豚草的理想生防菌。     

Antimicrobial activity of crude extracts from mangrove fungal endophytes

The aim of this work was to select endophytic fungi from mangrove plants that produced antimicrobial substances. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) or minimal fungicidal concentrations (MFC) of crude extracts from 150 isolates were determined against potential human pathogens by a colorimetric microdilution method. Ninety-two isolates (61.3%) produced inhibitory compounds. Most of the extracts (28–32%) inhibited Staphylococcus aureus (MIC/MBC 4–200/64–200 μg ml⁻¹). Only two extracts inhibited Pseudomonas aeruginosa (MIC/MBC 200/>200 μg ml⁻¹). 25.5 and 11.7% inhibited Microsporum gypseum and Cryptococcus neoformans (MIC/MFC 4–200/8–200 μg ml⁻¹ and 8–200/8–200 μg ml⁻¹, respectively), while 7.5% were active against Candida albicans (MIC/MFC 32–200/32–200 μg ml⁻¹). None of the extracts inhibited Escherichia coli. The most active fungal extracts were from six genera, Acremonium, Diaporthe, Hypoxylon, Pestalotiopsis, Phomopsis, and Xylaria as identified using morphological and molecular methods. Phomopsis sp. MA194 (GU592007, GU592018) isolated from Rhizophora apiculata showed the broadest antimicrobial spectrum with low MIC values of 8–32 μg ml⁻¹against Gram-positive bacteria, yeasts and M. gypseum. It was concluded that endophytic fungi from mangrove plants are diverse, many produce compounds with antimicrobial activity and could be suitable sources of new antimicrobial natural products.     

Abundance and composition of the summer phytoplankton community along a transect from the Barguzin River to the central basin of Lake Baikal

The abundance and composition of phytoplankton were investigated at six stations along a transect from the Barguzin River inflow to the central basin of Lake Baikal in August 2002 to clarify the effect of the river inflow on the phytoplankton community in the lake. The water temperature in the epilimnion was high near the shore at Station 1 (17.3°C), probably due to the higher temperature of the river water, and gradually decreased offshore at Station 6 (14.5°C). Thermal stratification developed at Stations 2–6, and a thermocline was observed at a 17–22-m depth at Stations 2–4 and an 8–12-m depth at Stations 5 and 6. The concentrations of nitrogen and phosphorus nutrients in the epilimnion at all stations were <1.0 μmol N l⁻¹ and <0.16 μmol P l⁻¹, respectively. Relatively high concentrations of nutrients (0.56–7.38 μmol N l⁻¹ and 0.03–0.28 μmol P l⁻¹) were detected in the deeper parts of the euphotic zone. Silicate was not exhausted at all stations (>20 μmol Si l⁻¹). The chlorophyll a (chl. a) concentration was high (>10 μg l⁻¹) near the shore at Station 1 and low (<3 μg l⁻¹) at five other stations. The <2 μm fraction of chl. a in Stations 2–6 ranged between 0.80 and 1.85 μg l⁻¹, and its contribution to total chl. a was high (>60%). In this fraction, picocyanobacteria were abundant at all stations and ranged between 5 × 10⁴ and 5 × 10⁵ cells ml⁻¹. In contrast, chl. a in the >2 μm fraction varied significantly (0.14–11.17 μg l⁻¹), and the highest value was observed at Station 1. In this fraction, the dominant phytoplankton was Aulacoseira and centric diatoms at Station 1 and Cryptomonas, Ankistrodesmus, Asterionella, and Nitzschia at Stations 2–6. The present study demonstrated the dominance of picophytoplankton in the pelagic zone, while higher abundance of phytoplankton dominated by diatoms was observed in the shallower littoral zone. These larger phytoplankters in the littoral zone probably depend on nutrients from the Barguzin River.     

Lecanosticta acicola, causal fungus of brown spot needle blight inPinus thunbergii, new to Japan

A needle blight disease with brown spots was found on ornamental trees ofPinus thunbergii in Shimane Prefecture, Japan. The causal fungus was identified asLecanosticta acicola, known as causal fungus of brown spot needle blight of pines recorded in the Americas, Europe, and China.Pinus thunbergii was heavily infected following inoculation with the fungus in June, but only slightly infected following inoculation in September. The mycelia of the fungus were raised and produced conidial masses on potato-dextrose and Waksman agars. They grew well at 20–25°C within the range of 5 to 35°C.     

Predation by zooplankton on <Emphasis Type="Italic">Batrachochytrium dendrobatidis</Emphasis>: biological control of the deadly amphibian chytrid fungus?

Batrachochytrium dendrobatidis (hereafter Batrachochytrium), a fungal pathogen of amphibians, causes the disease chytridiomycosis which is responsible for unprecedented population declines and extinctions globally. Host defenses against chytridiomycosis include cutaneous symbiotic bacteria and anti-microbial peptides, and proposed treatment measures include use of fungicides and bioaugmentation. Efforts to eradicate the fungus from localized areas of disease outbreak have not been successful. Instead, control measures to mitigate the impacts of the disease on host populations, many of which are already persisting with Batrachochytrium in an endemic state, may be more realistic. The infective stage of the fungus is an aquatic zoospore, 3–5 μm in diameter. Here we show that zoospores of Batrachochytrium are consumed by the zooplankter Daphnia magna. This species inhabits amphibian breeding sites where Batrachochytrium transmission occurs, and consumption of Batrachochytrium zoospores may lead to effective biological control of Batrachochytrium.     

Inhibition of ribonuclease and protease activities in germinating rice seeds exposed to nickel

When the seeds of two rice cvs. Malviya-36 and Pant-12 were germinated up to 120 h in the presence of 200 and 400 μM NiSO₄, a significant reduction in the germination of seeds occurred. Seeds germinating in the presence of 400 μM NiSO₄ showed about 12–20% decline in germination percent, about 20–53% decline in lengths and about 8–34% decline in fresh weights of roots and shoots at 120 h of germination. Ni²⁺ exposure of germinating seeds resulted in apparent increased levels of RNA, soluble proteins, and free amino acids in endosperms as well as embryo axes. A 400 μM Ni²⁺ treatment led to about 58–101% increase in the level of soluble proteins and about 39–107% increase in the level of free amino acids in embryo axes at 96 h of germination. Activities of ribonuclease and protease declined significantly with increasing levels of Ni²⁺ treatment. Isoenzyme profile of RNase as revealed by activity staining indicated decline in the intensities of 3–4 preexisting enzyme isoforms in embryo axes of both the rice cultivars and disappearance of one of the two isoforms in endosperms of cv. Pant-12 due to 400 μM Ni²⁺ treatment. Results suggest that the presence of high level of Ni²⁺ in the medium of germinating rice seeds serves as a stress factor resulting in decreased hydrolysis as well as delayed mobilization of endospermic RNA and protein reserves and causing imbalance in the level of biomolecules like RNA, proteins, and amino acids in growing embryo axes. These events would ultimately contribute to decreased germination of rice seeds in high Ni²⁺ containing environment.     

<Emphasis Type="Italic">Erysiphe fimbriata</Emphasis> sp. nov.: a powdery mildew fungus found on <Emphasis Type="Italic">Carpinus laxiflora</Emphasis>

Ascomata of a powdery mildew-like fungus have been found on Carpinus laxiflora in Tochigi Prefecture of Japan since 2003. The morphological and molecular characteristics of this fungus are reported, and a new species, Erysiphe fimbriata, is proposed. It has large chasmothecia (200–250 μm in diameter) with long (up to 4–5 mm in length), fimbriate appendages arising from the upper half of the chasmothecia and turning upward, and numerous asci (22–38 per chasmothecium). Erysiphe fimbriata is a unique fungus both genetically and morphologically.