Abstract: Despite the vast surface area of terrestrial plant leaves and the large microbial communities they support, little is known of the ability of leaf-associated microorganisms to access and degrade airborne pollutants. Here, we examined bacterial acquisition and degradation of phenol on leaves by an introduced phenol degrader and by natural phyllosphere communities. Whole-cell gfp-based Pseudomonas fluorescens bioreporter cells detected phenol on leaves that had previously been transiently exposed to gaseous phenol, indicating that leaves accumulated phenol; moreover, they accumulated it in sites that were accessible to epiphytic bacteria and to concentrations that were at least 10-fold higher than those in the air. After inoculated leaves were exposed to gaseous 14C-phenol, leaves harbouring the phenol-degrading Pseudomonas sp. strain CF600 released eight times more 14CO2 than did leaves harbouring a non-degrading mutant, demonstrating that CF600 actively mineralized phenol on leaves. We evaluated phenol degradation by natural microbial communities on green ash leaves that were collected from a field site rich in airborne organic pollutants. We found that significantly more phenol was mineralized by these leaves when the communities were present than by these leaves following surface sterilization. Thus, phenol-degrading organisms were present in these natural communities and were metabolically capable of phenol degradation. Collectively, these results provide the first direct evidence that bacteria on leaves can degrade an organic pollutant from the air, and indicate that bacteria on leaves could potentially contribute to the natural attenuation of organic air pollutants.

Abstract: Stomata are microscopic pores in the epidermis of the aerial parts of terrestrial plants. These pores are essential for photosynthesis, as they allow CO(2) to diffuse into the plant. The size of the stomatal pore changes in response to environmental conditions, such as light intensity, air humidity and CO(2) concentrations, as part of the plant's adaptation to maximize photosynthetic efficiency and, at the same time, to minimize water loss. Historically, stomata have been considered as passive portal of entry for plant pathogenic bacteria. However, recent studies suggest that stomata can play an active role in restricting bacterial invasion as part of the plant innate immune system. Some plant pathogens have evolved specific virulence factors to overcome stomata-based defence. Interestingly, many bacterial disease outbreaks require high humidity, rain, or frost damage, which could promote stomatal opening and/or bypass stomatal defence by creating wounds as alternative entry sites. Further studies on microbial and environmental regulation of stomata-based defence should fill gaps in our understanding of bacterial pathogenesis, disease epidemiology and phyllosphere microbiology.

Abstract: Aims: Despite the interest of phyllosphere microbiology, no studies have addressed the bacteria present in bract phyllosphere, an ecosystem that has special characteristics in palm trees because the dry bracts remain on the plant until pruning and may contain polymer-degrading bacteria involved in plant degradation. Therefore, the aim of this work was to characterize xylanolytic bacteria isolated from palm bract phyllosphere. Methods and Results: Twelve xylanolytic strains were isolated and characterized by phenotypic features and complete sequencing of 16S rRNA gene. The results showed that the isolates were phenotypically and genotypically diverse. Gram-positive isolates were classified into genus Paenibacillus some of them belonging to hitherto undescribed species of this genus. Gram-negative isolates were classified into genera Pseudomonas and Acinetobacter. Conclusions: The results of this work confirm the complexity of the bacterial populations present in phyllospheric ecosystems and suggest that bacteria involved in plant degradation are present at the early degradation steps of this process in dry palm tree bracts. Significance and Impact of the Study: This is the first study on bract phyllospheric bacteria able to hydrolyse vegetal polymers and offers a new perspective in the search of unexplored sources of xylanase-producing strains.

Abstract: The impact of conventional agrichemicals commonly used in New Zealand apple production on non-target, culturable phyllosphere microbial populations was studied in the laboratory (agar, leaf, and seedling assays) and field (apple orchard). Morphologically distinct bacteria (three), yeasts (five), and filamentous microfungi (two) were used as indicator species. The agar assay showed that agrichemical toxicity to microorganisms was dependent on product type, product rate, and organism studied. While the fungicides metiram and captan stopped or severely reduced growth of nearly all microorganisms studied, the insecticides tebufenozide and lufenuron and the fungicide nitrothal-isopropyl showed the least amount of microbial toxicity, each affecting 2 of the 10 indicator organisms studied. In the leaf assay a single agrichemical application at field rate either reduced or increased microbial population counts, again depending on product and microorganism. Repeated agrichemical applications, however, reduced micr...

Abstract: Many years of research has confirmed a wide distribution of anamorphous ascomycete yeasts in the phyllosphere of diverse plants of Moscow and the Moscow oblast. Based on the standard morphological and physiological criteria, on the results of restriction analysis of the 5.8S-ITS rDNA region, and on the sequencing of the D1D2 region of 26S rDNA, these yeasts were identified as Candida oleophila Montrocher. Previous iso- lation of this species has been rare, possibly due to its incorrect identification. This species, together with phy- tobiotic basidiomycete yeasts, was shown to be dominant in the yeast epiphytic communities on the surface parts of plants. The relative abundance of C. oleophila is highest on plant fruits and increases significantly by the end of the vegetation period. Wide occurrence of this yeast species on fruits and in the phyllosphere may be related to its ability to compete with rapidly growing phytopathogenic fungi.

Abstract: The annual dynamics of the number and taxonomic composition of yeast was studied in the rhizosphere of two plant species (Ajuga reptans L. and Taraxacum officinale Wigg.) in a forb-birch forest on soddy-podzolic soil. Eurybiont phyllobasidial cryptococci and red-pigmented phytobionts Rhodotorula glutinis were found to predominate in the phyllosphere of these plants, whereas the typical pedobionts Cryptococcus terricola and Cr. podzolicus occurred on the surface of roots and in the rhizosphere. The seasonal changes in the number and species composition of the yeast communities in the rhizosphere were more smooth as compared to those in the phyllosphere. In the period of active vegetation of the plants, the phytobiont yeasts develop over their whole surface, including the rhizoplane. Their number on the aboveground parts of the plants was significantly lower than that of the pedobiont forms. Thus, the above-and underground parts of the plants significantly differed in the composition of the dominant species of epiphytic yeasts.

Abstract: Aims: To assess the effects of solar UV-B radiation on phyllosphere bacteria of tea leaves in relation to blister blight disease in the field. Methods and Results: The effects of UV-B radiation on the phyllosphere microbiology of tea (Camellia sinensis) were studied in contrasting wet and dry seasons at a tropical site. Wavelength-selective filters were used to separate the effects of UV-B from those of other factors. Bacterial populations were quantified in relation to the incidence of blister blight disease. Attenuation of UV-B increased the survival of Xanthomonas sp. when populations were not water limited, and increased the incidence of blister blight, but had no effect on Corynebacterium aquaticum. Conclusions: The effects of solar UV-B on phyllosphere bacteria were substantial but depended on both species and interactions with other environmental variables. Xanthomonas sp. was more sensitive to UV-B than C. aquaticum, but this did not result in differences in population density under high radiation conditions (dry season), but only in the wet season when other factors were not limiting. Significance and Impact of the Study: The role of UV-B on leaf surface microbiology in the tropics is marked but depends on other conditions, and the contrasting UV-B responses of different organisms can be masked by other limiting factors.

Abstract: Rice is an important crop, widely affected by quite a number of diseases that results in higher yield losses. Among the fungal diseases, blast incited by Pyricularia oryzae is a major disease. The biological method of plant disease management seems to be an alternative to chemical fungicides in managing the blast disease. A new bio control agent viz., Serratia marcescens appears to be an ideal agent for the control of P. oryzae, because it produces chitinolytic enzymes which causes degradation of the fungal cell walls, induction of plant defence reaction and certain antifungal low molecular weight molecules. A study was undertaken to investigate the effect of a new bio control agent like S. marcescens against P. oryzae. The talc based formulation of S. marcescens (@ 1.0, 1.5, 2.0 and 2.5 kg/ha) was sprayed on old IR 50 rice plants in fields. Out of the six-bio protectants tested, S. marcescens was found very effective against P. oryzae under in vitro conditions. S. marcescens could be isolated from shoots as well as roots emerging from the treated seeds and the plant parts from treated seeds inhibited P. oryzae. The antagonist S. marcescens survived in the phyllosphere even 80 days after spray. The results revealed that rice blast control was achieved by spraying S. marcescens @ 1.0 kg/ha. The increasing dose of talc-based inoculum when applied on foliage increased the phyllosphere population of S. marcescens and controlled rice blast. The maximum disease control was achieved when inoculum was applied at 2.5 kg/ha.

Abstract: A psychrotolerant, halotolerant and alkalophilic yeast was isolated from fermented leaves of Camellia sinensis Kuntze, the tea plant. The yeast strain, named Tea-Y1, was both phenotypically and genotypically identified as belonging to the species Debaryomyces hansenii. This assignment was confirmed by scanning and transmission electron microscopy. The analysis of growth curves demonstrated the ability this yeast strain to grow in a temperature range between 4°C and 28°C, with an optimum of 23°C. The ecology of this yeast in the C. sinensis phyllosphere, as well as its possible role in tea fermentation and storage, with particular reference to iced tea, are discussed.

Abstract: Through collecting,isolating and cultivating the pine phyllosphere microbes,several isolates were selected to test their antagonistic effect to Sphaeropsis sapinea and Pestalotiopsis spBy the method of dual culture,the result showed that the isolates with obviously antagonistic ability to Sphaeropsis sapinea and Pestalotiopsis spcontained six kinds of bacteria,three kinds of yeast and three kinds of Trichodermas sp,which perhaps could be used for biological controlThe antagonistic effect of bacteria is the highest,secondly Trichoderma spand yeast lastlyThe standard for screening antagonistic fungus is relatively restraining the effect of a fungusAt the same time the restrained proportion and the characteristics leading to disease for the fungus should be considered

Abstract: The seemingly infinite variety of metabolic processes and products suggests potential for a correspondingly vast array of detection methodologies, and the scope of available technology for monitoring microbial metabolic activity is increasing so rapidly that it is difficult to catalog the available methods. Soil, the rhizosphere, and the phyllosphere are populated by complex communities of organisms, including microbes (bacteria, archaea, fungi, and protists) but also typically including plant and animal components. The rhizosphere and phyllosphere are defined by the presence of a plant, so it is inherently impossible to characterize microbial activity in these habitats through the study of genetically uniform microbial strains in isolation. Respirometry is increasingly being used for determination of biodegradation kinetics, and microcosm screening studies often are performed under controlled conditions to evaluate biodegradability potential and options for bioremediation. Several methods for estimating the metabolic activity levels of microbial populations involve quantification of cellular pools and rates of synthesis of specific biochemical components including RNA, DNA, ATP, and total adenine nucleotide. A number of methods for the quantification of metabolic activity and/or biomass of individuals, populations, or microbial communities involve direct microscopic observation of cells. This chapter has attempted to provide an overview of a number of these new methodologies, but it only presents a snapshot in time, as the number of new techniques and the opportunities they present for environmental microbiology continue to rapidly expand.

Abstract: A study was devised to evaluate the in-vitro antagonistic activity of the phylloplane fungal isolates against Alternaria alternata, causal agent of leaf blight of sesame. About 13 different phylloplane fungal isolates were screened to determine their in vitro antagonistic potential against A. alternata. Three of the isolates were found to be effective in controlling the growth of the test fungi. The significance of this study in biological control is discussed.

Abstract: Biological control of plant diseases by the application of antagonistic micro-organisms to the plant phyllosphere is only marginally understood. Suppression subtrac tive hybridization (SSH) was used for the identification of genes expressed after application of the non pathogenic bacterium Pseudomonas fluorescens Bk3 to the phyllosphere of the apple scab-susceptible cultivar Malus domestica cv. Holsteiner Cox. In total, 157 expressed sequence tag (EST) clones were obtained. The sequencing of 113 ESTs which have a significantly elevated transcript level and the com parison of the obtained sequences with databases revealed similarities to different classes of pathogenesis related proteins, for example, RNase-like PR10 protein and endochitinase, or similarities to proteins expressed under stress conditions that could have a protective function, for example, a germin-like protein, glutathione S-transferase, thioredoxin-like proteins, and heat shock proteins. In addition, several transcripts were identified that code for proteins which have a crucial role at different stages of pathogen recognition and in signal ling pathways or an as yet unknown function in plant defence. The results show that a number of transcripts encoding proteins/enzymes which are known to be up regulated after pathogen infection are also up-regulated after the application of a non-pathogenic bacterium to a M. domestica cultivar. The expression of these proteins might increase the plant resistance towards pathogen infection and damage.

Abstract: This paper is a review of the benefits of rhizosphere bacteria on plant nutrition. The interaction between plant and phosphate-solubilizing- bacteria is explained in more detail and used as model to illustrate the role that rhizosphere bacteria play on soil nutrient availability. Environmental conditions of rhizosphere and mycorrhizosphere are also discussed. Plants can release carbohydrates, aminoacids, lipids, and vitamins trough their roots to stimulate microorganisms in the soil. The soil volume affected by these root exudates, aproximately 2 mm from the root surface, is termed rhizosphere. Rhizosphere bacteria participate in the geochemical cycling of nutrients and determine their availability for plants and soil microbial community. For instance, in the rhizosphere there are organisms able to fix N 2 forming specialized structures (e.g., Rhizobium and related genera) or simply establishing associative relationships (e.g. Azospirillium, Acetobacter). On the other hand, bacterial ammonifiers and nitrifiers are responsible for the conversion of organic N compounds into inorganic forms (NH 4 + and NO 3 - ) which are available for plants. Rhizosphere bacteria can also enhance the solubility of insoluble minerals that control the availability of phosphorus (native or applied) using for that organic acids or producing phosphatases that act on organic phosphorus pools. The availability of sulfur, iron and manganese are also affected by redox reactions carried out by rhizosphere bacteria. Likewise, chelating agents can control the availability of micronutrients and participate in mechanisms of biocontrol of plant pathogens. Due to these and other benefits on plant growth, some rhizosphere bacteria have been called Plant Growth Promoting Rhizobacteria (PGPR). The benefits of PGPR have also been obtained, and even enhanced, in presence of mycorrhizal fungi. Some authors have employed the term "mycorrhizosphere" to describe the part of the soil affected by these interactions.

Abstract: The taxonomic position of a group of fluorescent pseudomonad strains isolated from the phyllosphere of grasses was investigated through a polyphasic approach. Riboprinting analysis revealed highly similar patterns for the investigated strains which supported, together with the agreement of many phenotypic characteristics, their affiliation to the same species. A comparison of 16S rRNA gene sequences of strain P 513/18(T), a representative strain from the grass isolates, revealed that it was affiliated to the cluster of the 'Pseudomonas fluorescens group', with Pseudomonas costantinii as the closest phylogenetic neighbour. However, DNA-DNA hybridization showed a clear demarcation at the species level between strain P 513/18(T) and P. costantinii. Furthermore, a comparison of riboprint patterns with Pseudomonas species clustering next to the novel grass isolates on the basis of 16S rRNA gene sequences supported their separate species status at the phylogenetic level. Based on phenotypic features, the novel isolates could also be differentiated from the other fluorescent Pseudomonas species that share positive arginine dihydrolase and oxidase reactions. As a consequence of these phenotypic and phylogenetic analyses, the isolates from the grass pyllosphere represent a novel species for which the name Pseudomonas lurida sp. nov. is proposed. The type strain is P 513/18(T) (=DSM 15835(T)=LMG 21995(T)).

Abstract: Aims: To evaluate the effect of plant variety and Azospirillum brasilense inoculation on the microbial communities colonizing roots and leaves of tomato (Lycopersicon esculentum Mill.) plants. Methods and Results: Seeds of cherry and fresh-market tomato were inoculated with A. brasilense BNM65. Sixty days after planting, plants were harvested and the microbial communities of the rhizoplane and phyllosphere were analysed by community-level physiological profiles (CLPP) using BIOLOG® EcoPlates and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes. Differences on the rhizoplane and phyllosphere bacterial communities between the two tomato types were detected by principal component analysis of the CLPP; DGGE fingerprints also showed differences at the phyllosphere level. Fresh-market tomato had a more complex phyllosphere bacterial community than cherry tomato, as determined by DGGE profiles. Physiological and genetic changes on phyllosphere and rhizoplane bacterial communities by Azospirillum seed inoculation were evident only on cherry tomato. Conclusions: Tomato genotype affects the response of native bacterial communities associated with the roots and leaves to A. brasilense seed inoculation. Significance and Impact of the study: The successful implementation of Azospirillum inoculation requires not only the consideration of the interactions between A. brasilense strains and plant genotypes, but also the plant-associated microflora.

Abstract: The activity of phyllosphere bacteria in the degradation of phenanthrene was investigated as a mechanism for the removal of atmospheric phenanthrene after its deposition on plant leaves. Initially, leaf samples of six plant species were collected from two roadsides in Bangkok to determine the presence of phenanthrene-degrading bacteria. The numbers of phenanthrene-degrading phyllosphere bacteria were varied and ranged from 3.5×104 to 1.95×107 CFU/g, in which the highest number was found from Ixora sp. Further studies were carried out in the laboratory by spraying phenanthrene on Ixora sp. leaves and then monitoring the amount of deposited phenanthrene and number of phenanthrene-degrading bacteria after incubation. The results showed that the amount of phenanthrene was significantly reduced on leaves containing phenanthrene-degrading bacteria. These were detected along with a rapid increase in the number of bacteria on leaves. The results indicated that many phyllosphere bacteria could utilize phenanthrene to support their growth and thereby reduce the amount of deposited phenanthrene on leaf surfaces. Several phenanthrene-degrading bacteria were later isolated from the leaves and identified with a high 16S rDNA sequence similarity to the genera Pseudomonas, Microbacterium, Rhizobium, and Deinococcus.

Abstract: Life History and Genetic Strategies 1 Evolutionary ecology of the first fungi J.H. Andrews and R.F. Harris 2 Molecular approaches for studying fungi in the environment K. Brunner, S. Zeilinger and R.L. Mach Determinants of Fungal Communities 3 Disturbances in natural ecosystems: scaling from fungal diversity to ecosystem functioning S.J. Morris, C.F. Friese, and M.F. Allen 4 Fungal Responses to Disturbance: agriculture and forestry R.M. Miller and D.J. Lodge 5 Fungi and industrial pollutants G.M. Gadd 6 Fungi in extreme environments N. Magan 7 Biogeography and conservation E.J.M. Arnolds Fungal Interactions and Biological Control Strategies 8 Mycoparasitism and antagonism A. Viterbo, J. Inbar, Y. Hadar and I. Chet 9 Antagonism of plant parasitic nematodes by fungi S. Casas-Flores and A. Herrera-Estrella 10 Entomopathogenic Fungi and their role in Pest Control A.K. Charnley and S. A. Collins 11 Bacterial weapons of fungal destruction: Phyllosphere targeted biological control of plant pathogens W. G. Dilantha Fernando, R. Ramarathnam and T. de Kievit 12 Effects of animals grazing on fungi. T. McGonigle 13 Endophytic Fungi P. Bayman 14 Mycorrhizal fungi: their habitats and nutritional strategies M. Girlanda, S. Perotto and P. Bonfante 15 Applications of fungal ecology in the search for new bioactive fungal products J.B. Gloer Decomposition, Biomass and Industrial Applications 16 Nutrient cycling by saprophytic fungi interrestrial habitats J. Dighton 17 Decomposition of plant litter by fungi in marine and freshwater ecosystems M.O. Gessner, V. Gulis, K. Kuehn, E. Chauvet and K. Suberkropp 18 Degradation of cellulose and hemicellulose polymers by fungi C. Gamauf, B. Metz and B. Seiboth

Abstract: Year-round studies of epiphytic yeast communities revealed that the number of ascosporogenous yeasts of the genus Saccharomyces inhabiting living and decaying leaves of some plants increased considerably in certain short periods (at the beginning of summer and in winter). Massive isolation of saccharomycetes was performed from 11 plant species; earlier, these yeasts had been revealed mainly in sugar-rich substrates. The isolates were identified as Saccharomyces paradoxus based on their physiological properties and RELP analysis of 5.8S-ITS. Possible reasons for short-term increases in the number of saccharomycetes in plant phyllosphere are discussed.

Abstract: SUMMARY Biological control of apple and pear fire blight creates an interesting alternative for chemical method and can serve as a supplementary one in integrated strategy of the disease control. At present, for protection of apple and pear during bloom, the biopreparations based on bacteria Pantoea agglomerans, Pseudomonas fluorescens, Bacillus subtilis and B. pumilis as well as on yeasts Aureobasidium pullulans and Metschnikowia pulcherrima are registered in some countries and used in practice. The research on improvement of their efficacy and on selection of new effective strains is also performed. Recently, new species of bacteria Erwinia tasmaniensis, E. billingiae and Rhanella aquatilis , showing protective potential against fire blight, are investi-gated. Our research allowed selecting from bacterial populations of apple phyllosphere and soil six isolates which were highly effective in protection of apple trees and pear fruitlets. Some of them inhibited growth of E. amylovora on artificial media and some produced lactones of homos-erine (AHL) indicating their ability to act on other bacteria (Quorum Sensing).