Comparison between Tuber gennadii and T. oligospermum lineages reveals the existence of the new species T. cistophilum (Tuberaceae, Pezizales)

New collections of T. gennadii, T. oligospermum and T. asa (Tuberaceae, Pezizales) from the Mediterranean basin were compared on the basis of morphology and DNA sequences. Phylogenetic inference based on the internal transcribed spacer region (ITS) and the 28S nuclear large ribosomal subunit (nrLSU) indicates that T. gennadii includes at least two lineages with characteristic morphological traits. T. gennadii s. str. has small subglobose ascomata with conspicuous glebal locules that form a continuous labyrinth when mature and has a prosenchymatic peridium. T. lacunosum has medium to large, deeply lobed ascomata with small to very small isolated locules when mature and has a pseudoparenchymatic peridium. Two major clades were identified within the T. oligospermum group. On the basis of morphological, ecological and biogeographical data, these are identified with the taxa T. oligospermum (= T. asa) and T. sphaerospermum. Tuber oligospermum forms small to medium globose or subglobose, whitish ascomata, with globose to broadly ellipsoidal ascospores and is found in alkaline, sandy soils. Tuber sphaerospermum forms medium to large, irregularly globose or deeply lobed, yellowish ascomata, with regularly globose ascospores and is found in acidic soils. Finally, a new truffle species with a prosenchymatic peridium and globose to ellipsoid reticulate spores, collected in acidic argillaceous soils of Spain under Cistus ladanifer is proposed here as the new species T. cistophilum.     

散囊菌属的两个新种

本文报道两个新种,肋状散囊菌(Eurotium costiforme)和少疣散囊菌(E.parviver-ruculosum)。前者的主要特征是子囊孢子的凸面有许多网结的肋状突起;在查氏琼脂上产生大量的闭囊壳,但分生孢子结构极少。后者在查氏琼脂上生长很局限;子囊孢子大,凸面近于平滑或有少量小疣等主要特点。     

Three new genera representing novel lineages of Sordariomycetidae (Sordariomycetes, Ascomycota) from tropical freshwater habitats in Costa Rica

Three new genera are established in the Sordariomycetidae based on morphological and molecular data (SSU and LSU nrDNA) to accommodate five ascomycete species collected from submerged woody debris in freshwater habitats from Costa Rica. The genus Bullimyces contains three new species, B. communis, B. costaricensis and B. aurisporus. Bullimyces is characterized by globose to subglobose, membranous, black, ostiolate ascomata; deliquescent, hyaline, globose cells that fill the center of the centrum; unitunicate asci that deliquesce early in some species; and septate, thick-walled ascospores with or without gelatinous sheaths or appendages. Bullimyces species form a well supported clade with 100% bootstrap support, but the position of the genus in the Sordariomycetidae remains unclear. The second genus, Riomyces, is represented by a single species, R. rotundus. Riomyces is characterized by globose to subglobose, membranous, black, ostiolate ascomata, unitunicate, cylindrical asci, hyaline, globose cells that fill the hamathecium and septate, thick-walled ascospores with a gelatinous sheath. Although Riomyces is morphologically similar to Bullimyces, the two genera did not group together with support in any analysis. The third genus, Hydromelitis, is represented by a single species, H. pulchella. Hydromelitis is characterized by pyriform, membranous, black, ostiolate ascomata, unitunicate asci lacking an apical structure, simple, thin-walled, septate paraphyses and hyaline to golden yellow, multiseptate, thick-walled ascospores with a gelatinous sheath. Bullimyces, Riomyces and Hydromelitis were nested within an unsupported clade consisting of members of the Ophiostomatales, Magnaporthales and freshwater Annulatacaceae sensu lato and sensu stricto.     

分离自西藏的两个散囊菌新种

本文报道两个新种:粪生散囊菌(Eurotium fimicola)和旱生散囊菌(Eurotium aridicola),它们不同于已报道的该属诸种。     

Freshwater ascomycetes: Natipusillaceae, a new family of tropical fungi, including Natipusilla bellaspora sp. nov. from the Peruvian Amazon

A new ascomycete species, Natipusilla bellaspora, collected from submerged woody debris in a freshwater stream at Los Amigos Biological Station, Madre De Dios in the Peruvian Amazon is described and illustrated. This fungus is characterized by small, globose to subglobose, hyaline ascomata; small, globose to subglobose, eight-spored fissitunicate asci; one-septate, multiguttulate ascospores with two different gelatinous sheaths, an outer amorphous sheath that enlarges in water and an inner sheath that has a distinctive persistent shape and is attached to the ascospore apex. Morphologically N. bellaspora differs from other Natipusilla species in having larger ascospores and two ascospore sheaths. A second Natipusilla species, N. limonensis, is reported for the first time from Peru. Based on the unique morphological characters of taxa in Natipusilla and results of previous molecular phylogenetic analyses with other members of the Dothideomycetes, we establish Natipusillaceae fam. nov. for this unique tropical freshwater clade.     

Isolation and characterisation of Aspergillus awamori BS05, a root-knot-nematode-trapping fungus

Nematode-trapping fungi are important biocontrol agents against parasitic nematodes through adhesive or mechanical hyphal traps. Aspergillus awamori, a root-knot-nematode-trapping fungus from tomato rhizosphere soil, was identified based on morphology and molecular characteristics of internal transcribed spacer DNA sequence. Conidial heads were white to black brown, loosely globose, and 72–127 μm in diameter. Conidiophores usually arose from the foot cell of basal mycelium, straight, and 960–1730 × 10.2–13.4 μm, hyaline to pale brown, not constricted below the vesicles; vesicles hemispherical to elongate, 43–56 μm in diameter, black brown, fertile over the upper half to two-thirds. Aspergilla were biseriate, and metulae were variable, 12–26 × 3.8–4.7 μm; phialides were 8.2–9.4 × 2.5–3 μm. Conidia were globose or subglobose, 3.6–4.8 μm in diameter, rough, grey brown and parallel in chains. A. awamori BS05 showed 44.9% control efficacy against Meloidogyne incogtina in pot experiments which suggests it as a potential biocontrol agent against Meloidogyne. This is the first report on A. awamori as nematode-trapping fungus.     

Variability in susceptibility among cucumber and tomato strains of Tetranychus urticae Koch to 2-tridecanone from tomato trichomes: effects of host plant shift

The effects of secondary plant compounds on different host races/strains of a herbivorous arthropod are not easy to interpret based on dose–response tests alone. This difficulty arises because the responses in a population to a given dose are dictated not only by genetic factors, but also by factors such as feeding history, age and plant. To discriminate between these possibilities different strains of a herbivorous mite (Tetranychus urticae Koch) were exposed to one relevant toxin from glandular hairs on tomato (the methyl ketone, 2-tridecanone) and these strains had a known feeding history on either or both of two host plants (tomato and cucumber). It was hypothesized that tomato is a relatively hostile host plant to spider mites partly due to methyl ketones from glandular hairs and that consequently there will be stronger selection on the tomato strains than on the cucumber strains. However, the expected differences between the tomato and cucumber strains did not show up; three spider mite strains collected from tomato and two strains collected from cucumber appeared to be equally susceptible to 2-tridecanone. This unexpected result cannot result from selection for resistance to 2-tridecanone, but it may be the consequence of cross-resistance to other ketones in cucumber or the bio-accumulation (i.e. metabolic load) of 2-tridecanone prior to the toxicity test. To test this hypothesis, one of the tomato strains was released on cucumber for different time intervals and one of the cucumber strains on tomato. It was found that the resistance of the tomato strain to 2-tridecanone increased 6 months after transfer to cucumber. This increased resistance cannot be the result of selection because 2-tridecanone is absent from cucumber. Hence, it may be due either to selection for resistance to another ketone in cucumber, possibly leading to cross-resistance, or to the absence of 2-tridecanone bioaccumulation on cucumber. Transfer of the cucumber strain from cucumber to tomato also increased the resistance to 2-tridecanone. As this was accompanied by high mortality directly after the transfer, selection for resistance may have played a role. Alternatively, the increased resistance may be due to induction of resistance to secondary plant compounds of tomato, including 2-tridecanone. In conclusion, experiments on host plant transfer show that the tomato strain and the cucumber strain are not equal in their resistance to 2-tridecanone.     

Host race formation inTetranychus urticae: genetic differentiation, host plant preference, and mate choice in a tomato and a cucumber strain

The two-spotted spider mite,Tetranychus urticae Koch, occurs in two colour forms in greenhouses in the Netherlands: a red form on tomato and a green form on cucumber. The evolutionary status of these strains was analysed by studying genetic differentiation, host plant preference, and mate choice. Males of the tomato strain preferred the female (30 h-old) teleiochrysales from the same strain to those of the cucumber strain, independent of the host plants (tomato, cucumber, bean) on which the teleiochrysales were placed. In contrast, males of the cucumber strain were not selective. In a Y-tube olfactometer, females of the cucumber strain were not responsive to host plant volatiles alone. However, in two-choice disc experiments, where females were exposed to both volatile and contact cues, they settled on cucumber leaves in preference to tomato leaves. Females of the tomato strain preferred the odour of tomato leaves and settled on tomato leaves in preference to cucumber leaves. These experimental results provide the first evidence for (1) host-plant independent mate selection in male spider mites and (2) olfactory discrimination between host plants in female spider mites. Electrophoretic analysis showed much genetic differentiation at the phosphoglucose isomerase locus. The cucumber strain showed large variation with 5 alleles, whereas the tomato strain was fixed for the most common allele of the cucumber strain. The results suggest that the two strains represent host races. We hypothesize that the tomato strain has originated from the cucumber strain because (1) tomato represents a more hostile host plant to spider mites (due to toxic compounds and glandular hairs) and (2) the tomato strain is genetically impoverished suggesting that it passed through one or more bottlenecks.     

Resistance to 2-tridecanone in Tetranychus urticae: effects of induced resistance,cross-resistance and heritability

Earlier studies of resistance to the tomato toxin 2-tridecanone revealedsimilar levels of resistance among tomato and cucumber strains ofTetranychus urticae, whereas we anticipated the tomatostrains to have a higher resistance. Between-strain differences, however, maybeconcealed by toxin accumulation and/or cross-resistance. Mites do accumulate2-tridecanone to a considerable extent, but we have shown before that thiscannot explain the lack of difference in resistance. In this paper, we provideevidence against cross-resistance: selection for resistance to a homologouscompound from cucumber, 2-nonanone, did not confer resistance to 2-tridecanone.Observed increases in resistance levels over generations may be due toinductionor selection. To study induction, adult females from a cucumber strain and atomato strain were exposed to a sublethal dose of 2-tridecanone. One day afterexposure, the cucumber strain gained in resistance to 2-tridecanone (c.8-fold),whereas the tomato strain showed a decrease in resistance. These changes inresistance disappeared within three days after exposure, the time the mitesneedto dispose themselves of the toxin. The results support earlier findings thatresistance is induced in the cucumber strain, but not in the tomato strain. Toassess the heritability of resistance to 2-tridecanone, offspring was obtainedfrom individual females, and both the mothers and their offspring were testedfor resistance. For the cucumber strain, offspring from susceptible orresistantmothers did not differ in resistance. For the tomato strain, however, offspringfrom resistant mothers were significantly more resistant to the toxin thanoffspring from susceptible mothers. This result provides unambiguous evidencethat resistance to 2-tridecanone can be selected for.     

Organic acids, sugars, and L-tryptophane in exudates of vegetables growing on stonewool and their effects on activities of rhizosphere bacteria

The influence of stonewool substrate on the exudation of the major soluble carbon nutrients and of the auxin precursor tryptophane for Pseudomonas biocontrol agents was studied. To this end, the composition of the organic acids and sugars, as well that of tryptophane, of axenically collected exudates of seed, seedlings, and roots of tomato, cucumber, and sweet pepper was determined. The major results were as follows. i) The total amount of organic acid is much higher than that of total sugar. ii) Exudation of both organic acids and sugars increases during plant growth. iii) Citric, succinic, and malic acids represent the major organic acids, whereas fructose and glucose are the major sugars. iv) Compared with glass beads as a neutral substrate, stonewool substantially stimulates exudation of organic acids and sugars. v) It appeared that enhanced root-tip-colonizing bacteria isolated previously from the rhizosphere of tomato and cucumber grow much better in minimal medium with citrate as the sole carbon source than other, randomly selected rhizobacteria do. This indicates that the procedure which selects for excellent root-tip colonizers enriches for strains which utilize the major exudate carbon source citrate. vi) The content of L-tryptophane, the direct precursor of auxin, is approximately 60-fold higher in seedling exudates of tomato and sweet pepper than in cucumber seedling exudates, indicating a higher possibility of plant growth stimulation after inoculation with auxin-producing rhizobacteria for tomato and sweet pepper crops than for cucumber. However, the biocontrol strain Pseudomonas fluorescens WCS365, which is able to convert tryptophane into auxin, did not stimulate growth of these three crops. In contrast, this strain did stimulate growth of roots of radish, a plant which exudes nine times more tryptophane than tomato does.     

天仙子族(茄科)的花粉形态补充研究及其系统学意义

在扫描电镜下研究了茄科天仙子族7属及颠茄属、茄参属和枸杞属3属共10属23种植物的花粉形态学特征。结果表明:天仙子族的花粉粒形状为球形、近球形、扁球形和长球形;萌发孔类型有无萌发孔、不规则的拟孔、3沟、4沟、3～4沟、散沟和3孔沟;外壁纹饰为小刺状、瘤状、各式条纹状、条纹-穴状、条纹-网状、皱波状、细网状和网状。沟膜近光滑、具小颗粒、具小刺状突起或具瘤状突起。各属植物的花粉形态在萌发孔的有无、萌发孔的类型和外壁纹饰等方面有较大的差异,可以作为探讨属间分类和系统关系的重要依据。天仙子族植物花粉萌发孔的演化趋势为:无萌发孔→3、4沟→3孔沟。无萌发孔的山莨菪属是原始类群,三孔沟的马尿泡和天仙子等属是进化类群。还讨论了与前人研究结果不同之处和可能的原因。     

Effects of host plant on life‐history traits in the polyphagous spider mite Tetranychus urticae

Studying antagonistic coevolution between host plants and herbivores is particularly relevant for polyphagous species that can experience a great diversity of host plants with a large range of defenses. Here, we performed experimental evolution with the polyphagous spider mite Tetranychus urticae to detect how mites can exploit host plants. We thus compared on a same host the performance of replicated populations from an ancestral one reared for hundreds of generations on cucumber plants that were shifted to either tomato or cucumber plants. We controlled for maternal effects by rearing females from all replicated populations on either tomato or cucumber leaves, crossing this factor with the host plant in a factorial design. About 24 generations after the host shift and for all individual mites, we measured the following fitness components on tomato leaf fragments: survival at all stages, acceptance of the host plant by juvenile and adult mites, longevity, and female fecundity. The host plant on which mite populations had evolved did not affect the performance of the mites, but only affected their sex ratio. Females that lived on tomato plants for circa 24 generations produced a higher proportion of daughters than did females that lived on cucumber plants. In contrast, maternal effects influenced juvenile survival, acceptance of the host plant by adult mites and female fecundity. Independently of the host plant species on which their population had evolved, females reared on the tomato maternal environment produced offspring that survived better on tomato as juveniles, but accepted less this host plant as adults and had a lower fecundity than did females reared on the cucumber maternal environment. We also found that temporal blocks affected mite dispersal and both female longevity and fecundity. Taken together, our results show that the host plant species can affect critical parameters of population dynamics, and most importantly that maternal and environmental conditions can facilitate colonization and exploitation of a novel host in the polyphagous T. urticae, by affecting dispersal behavior (host acceptance) and female fecundity.     

中国木霉属两个新种

报道了采自我国海南省和福建省的木霉属Trichoderma 2个新种。南方木霉子座紫色至紫红色,垫状至盘状,子囊壳壁橙色至橙褐色,子囊孢子无色;绿黄木霉具有淡黄色子座,绿色孔口,球形至近球形的子囊壳,以及大的子囊和绿色子囊孢子。提供了这2个种的详细描述及宏观和微观特征的图示。     

A new species ofCortinarius Sect.Hydrocybe from Japan

Cortinarius laccarioides sp. nov., found in deciduous forests, is described and illustrated. It is characterized by its small hygrophanous pileus, greyish red or greyish violet lamellae and stipe, and globose to subglobose basidiospores. The differences betweenC. laccarioides and similar species are briefly discussed.     

THE EFFECT OF CERTAIN BENZAZOLE COMPOUNDS ON PLANT GROWTH AND DEVELOPMENT

Klingensmith , M. J. (Colgate U., Hamilton, N. Y.) The effect of certain benzazole compounds on plant growth and development. Amer. Jour. Bot. 48(1): 40–45. Illus. 1961.—A number of benzazoles, in particular benzimidazole, benzothiazole, and benzotriazole, were examined for their effects on growth of seedlings and established plants. Benzothiazole was the most active in repressing elongation of the primary root of cucumber. Benzimidazole and benzotriazole were about 1/10 as active. Adenine was without effect in reversing the benzazole-induced inhibition of cucumber root elongation and, in fact, supplemented the inhibition caused by benzimidazole and benzothiazole. Application of benzotriazole to the root medium of bean, coleus, tomato, oat and wheat caused a pronounced inhibition of internodal elongation with a stimulation of axillary development. Distinct morphological changes were observed which did not correspond to those produced by other growth regulators. Application of benzimidazole to the root medium of several genera of plants resulted in injury to laminar tissue followed by desiccation, with no concomitant effect on the stem. Application of benzothiazole to the root medium induced development of adventitious roots in bean and tomato. This compound also caused initiation of roots on cultures of tobacco-stem segments, while not suppressing bud development. The benzazoles tested seem to be of a different class of compounds from other growth regulators which have been studied. The responses elicited by treatment with each of the 3 benzazoles are distinctly characteristic and are dependent on the structure of the azole portion of the molecule.     

Reducing Meloidogyne incognita Injury to Cucumber in a Tomato-Cucumber Double-Cropping System

The effects of a root-knot nematode-resistant tomato cultivar and application of the nematicide ethoprop on root-knot nematode injury to cucumber were compared in a tomato-cucumber double-cropping system. A root-knot nematode-resistant tomato cultivar, Celebrity, and a susceptible cultivar, Heatwave, were grown in rotation with cucumber in 1995 and 1996. Celebrity suppressed populations of Meloidogyne incognita in the soil and resulted in a low root-gall rating on the subsequent cucumber crop. Nematode population densities were significantly lower at the termination of the cucumber crop in plots following Celebrity than in plots following Heatwave. Premium and marketable yields of cucumbers were higher in plots following Celebrity than in plots following Heatwave. Application of ethoprop through drip irrigation at 4.6 kg a.i./ha reduced root galling on the cucumber crop but had no effect on the nematode population density in the soil at crop termination. Ethoprop did not affect cucumber yield. These results indicate that planting a resistant tomato cultivar in a tomato-cucumber double-cropping system is more effective than applying ethoprop for managing M. incognita.     

A new species ofNannizziopsis from New Jersey soil

Nannizziopsis mirabilis, isolated from a soil sample collected from New Jersey, USA, is described as a new species. The ascomata are white to pale yellow, with a peridium of a network of loosely interwoven hyphae and simple, more or less straight, clavate appendages. The ascospores are hyaline, globose to subglobose, and ornamented with spiral bands or sometimes polygonal pits. The associated anamorph is assignable to the form genusChrysosporium.     

Evidence for two photoreceptors controlling growth in de-etiolated seedlings

The effect of blue light on hypocotyl extension in de-etiolated seedlings of lettuce, cucumber and tomato was investigated under conditions which precluded the involvement of phytochrome. Small but highly inhibitory amounts of blue light were added to a high intensity background illumination from low pressure sodium lamps. A log-linear response for inhibition of hypocotyl extension against the blue light fluence rate was obtained for lettuce and cucumber, and inhibition in tomato was also related to the blue light fluence rate. The added blue light did not alter phytochrome photostationary state and its effect was independent of the total fluence rate. Growth inhibition by Pfr could be demonstrated in tomato and cucumber but not in lettuce. The results indicate that two photoreceptors may normally be involved in the control of seedling growth but their relative importance varies greatly between species.Abbreviations HIR high irradiance reaction - Pfr far red absorbing form of phytochrome - Pr red absorbing form of phytochrome     

Discovery of the second species of Pseudohypocrea (Hypocreaceae)

A new species of the monotypic genus Pseudohypocrea is described based on a collection from Tai Po Kau, Hong Kong, China. The fungus is characterized by globose to subglobose perithecia entirely immersed in a pulvinate reddish-brown stroma, cylindrical asci with smooth-walled and lemon-shaped part-ascospores, and occurring on dead leaves. Morphological features of the new species are described and compared with the only known species of the genus.poi