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1.
PLoS One ; 15(10): e0240093, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33031481

RESUMO

Flowers produce an array of nutrient-rich exudates in which microbes can thrive, making them hotspots for microbial abundance and diversity. During a diversity study of yeasts inhabiting the flowers of Metrosideros polymorpha (Myrtaceae) in the Hawai'i Volcanoes National Park (HI, USA), five isolates were found to represent two novel species. Morphological and physiological characterization, and sequence analysis of the small subunit ribosomal RNA (rRNA) genes, the D1/D2 domains of the large subunit rRNA genes, the internal transcribed spacer (ITS) regions, and the genes encoding the largest and second largest subunits of the RNA polymerase II (RPB1 and RPB2, respectively), classified both species in the family Metschnikowiaceae, and we propose the names Candida metrosideri pro tempore sp. nov. (JK22T = CBS 16091 = MUCL 57821) and Candida ohialehuae pro tempore sp. nov. (JK58.2T = CBS 16092 = MUCL 57822) for such new taxa. Both novel Candida species form a well-supported subclade in the Metschnikowiaceae containing species associated with insects, flowers, and a few species of clinical importance. The ascosporic state of the novel species was not observed. The two novel yeast species showed elevated minimum inhibitory concentrations to the antifungal drug amphotericin B (>4 µg/mL). The ecology and phylogenetic relationships of C. metrosideri and C. ohialehuae are also discussed.


Assuntos
Candida/classificação , Myrtaceae/microbiologia , Anfotericina B/farmacologia , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/genética , Candida/isolamento & purificação , Farmacorresistência Fúngica , Flores/microbiologia , Hawaii , Testes de Sensibilidade Microbiana , Fenótipo , Filogenia , RNA Ribossômico/classificação , RNA Ribossômico/genética , RNA Ribossômico/metabolismo
2.
PLoS One ; 15(9): e0237561, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877468

RESUMO

In increasingly urban landscapes, the loss of native pollen and nectar floral resources is impacting ecologically important pollinators. Increased urbanization has also brought about the rise of urban gardens which introduce new floral resources that may help replace those the pollinators have lost. Recently, studies have shown that the microbial communities of nectar may play an important role in plant-pollinator interactions, but these microbial communities and the floral visitors in urban environments are poorly studied. In this study we characterized the floral visitors and nectar microbial communities of Ascelpias curassavica, a non-native tropical milkweed commonly, in an urban environment. We found that the majority of the floral visitors to A. curassavica were honey bees followed closely by monarch butterflies. We also found that there were several unique visitors to each site, such as ants, wasps, solitary bees, several species of butterflies and moths, Anna's hummingbird, and the tarantula hawk wasp. Significant differences in the nectar bacterial alpha and beta diversity were found across the urban sites, although we found no significant differences among the fungal communities. We found that the differences in the bacterial communities were more likely due to the environment and floral visitors rather than physiological differences in the plants growing at the gardens. Greater understanding of the impact of urbanization on the nectar microbiome of urban floral resources and consequently their effect on plant-pollinator relationships will help to predict how these relationships will change with urbanization, and how negative impacts can be mitigated through better management of the floral composition in urban gardens.


Assuntos
Asclepias/microbiologia , Microbiota , Néctar de Plantas , Clima Tropical , Urbanização , Bactérias/crescimento & desenvolvimento , Biodiversidade , Flores/microbiologia , Fungos/crescimento & desenvolvimento
3.
Int J Syst Evol Microbiol ; 70(8): 4496-4501, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32628104

RESUMO

Two yeast strains representing a novel species in the basidiomycetous yeast genus Naganishia were isolated from flowers of Sorbaria sorbifolia collected in Beijing Olympic Forest Park, PR China. Results of multi-gene phylogenetic analysis indicated that the two strains were closely related to the type strains of Naganishia bhutanensis (CBS 6294T) and Naganishia antarctica (CBS 7687T). However, the new isolates differed from N. bhutanensis CBS 6294T by 1.79 % sequence divergence in the D1/D2 domain (11 nt substitutions and three indels), and 2.42 % (15 nt differences and one indel) to N. antarctica CBS 7687T. In the ITS region, the new isolates showed 1.15 % divergence (7 nt substitutions and one indel) to N. bhutanensis CBS 6294T and 0.92 % divergence (5 nt substitutions and no indels) to N. antarctica CBS 7687T. A phylogenetic analysis employing the sequences of six genes (D1/D2 domain of large subunit rDNA, ITS, small subunit rDNA, two subunits of the RNA polymerase II and elongation factor-1α) indicated that the novel species belonged to the genus Naganishia and formed a well-supported clade with N. bhutanensis, N. antarctica and N. indica. Moreover, the two strains differed from their closest relatives by the ability to grow on distinct carbon and nitrogen sources and ability to grow at 30 °C. On the basis of these findings, we propose a novel species in the genus Naganishia (Filobasidiales), Naganishia floricola sp. nov. (holotype CGMCC 2.5856).


Assuntos
Basidiomycota/classificação , Flores/microbiologia , Filogenia , Rosaceae/microbiologia , Basidiomycota/isolamento & purificação , China , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Técnicas de Tipagem Micológica , Análise de Sequência de DNA
4.
Mol Plant Microbe Interact ; 33(9): 1129-1141, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32689871

RESUMO

Phytoplasmas are intracellular bacterial plant pathogens that cause devastating diseases in crops and ornamental plants by the secretion of effector proteins. One of these effector proteins, termed SECRETED ASTER YELLOWS WITCHES' BROOM PROTEIN 54 (SAP54), leads to the degradation of a specific subset of floral homeotic proteins of the MIKC-type MADS-domain family via the ubiquitin-proteasome pathway. In consequence, the developing flowers show the homeotic transformation of floral organs into vegetative leaf-like structures. The molecular mechanism of SAP54 action involves binding to the keratin-like domain of MIKC-type proteins and to some RAD23 proteins, which translocate ubiquitylated substrates to the proteasome. The structural requirements and specificity of SAP54 function are poorly understood, however. Here, we report, based on biophysical and molecular biological analyses, that SAP54 folds into an α-helical structure. Insertion of helix-breaking mutations disrupts correct folding of SAP54 and compromises SAP54 binding to its target proteins and, concomitantly, its ability to evoke disease phenotypes in vivo. Interestingly, dynamic light scattering data together with electrophoretic mobility shift assays suggest that SAP54 preferentially binds to multimeric complexes of MIKC-type proteins rather than to dimers or monomers of these proteins. Together with data from literature, this finding suggests that MIKC-type proteins and SAP54 constitute multimeric α-helical coiled coils. Our investigations clarify the structure-function relationship of an important phytoplasma effector protein and may thus ultimately help to develop treatments against some devastating plant diseases.


Assuntos
Proteínas de Bactérias/química , Flores/microbiologia , Phytoplasma/genética , Doenças das Plantas/microbiologia , Proteínas de Bactérias/genética , Plantas , Estrutura Secundária de Proteína , Relação Estrutura-Atividade
5.
Arch Microbiol ; 202(7): 1965-1976, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32474645

RESUMO

No genomic sequence of Mycobacterium isolated from orchids has been reported yet; therefore, this study intends to analyze the complete genomic sequence of a growth-promoting Mycobacterium from orchid Doritaenopsis. Mycobacterium strain Mya-zh01 was isolated from the flower stalk of Doritaenopsis Jiuhbao Red Rose. Our results show that Mya-zh01 can effectively produce and secrete the plant growth hormone indole-3-acetic acid (IAA). Inoculation of Mya-zh01 increased root number and length, plant height, leaf number, and leaf length in Doritaenopsis. Furthermore, inoculation of Mya-zh01 promotes seed germination in Doritaenopsis. We sequenced and assembled chromosome for Mya-zh01 (5,027,704 bp with 68.48% GC content), which was predicted to encode 4968 proteins with functions in oxidation reduction, growth, plasma membrane, ATP and DNA binding, carbon metabolism and biosynthesis of amino acids pathways. Mya-zh01 may trap iron from nature or host cells to facilitate the growth of the orchids by producing two siderophores (Mycobactin and Nocobactin NA). Four pathways (tryptamine, indole-3-acetamide, indole-3-pyruvate, and flavin monooxygenase) and seven enzymes [tryptophan synthase alpha chain, tryptophan synthase beta chain, amidase, monoamine oxidase, indole-3-pyruvate monooxygenase, indole-3-pyruvate decarboxylase and aldehyde dehydrogenase (NAD +)] involved in IAA biosynthesis were predicted in Mya-zh01 genome. In conclusion, this study demonstrated the significance of Mya-zh01 in facilitating plant growth and seed germination in Doritaenopsis by IAA biosynthesis, which provides a new insight into the mechanism of plant-bacteria interaction in Doritaenopsis.


Assuntos
Mycobacterium/genética , Orchidaceae/microbiologia , Desenvolvimento Vegetal , Sementes/microbiologia , Flores/microbiologia , Germinação , Mycobacterium/isolamento & purificação , Mycobacterium/metabolismo
6.
PLoS One ; 15(5): e0233916, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470037

RESUMO

The olive tree (Olea europaea L.) is the most important oil-producing crop of the Mediterranean basin. However, although plant protection measures are regularly applied, disease outbreaks represent an obstacle towards the further development of the sector. Therefore, there is an urge for the improvement of plant protection strategies based on information acquired by the implementation of advanced methodologies. Recently, heavy fungal infections of olive fruits have been recorded in major olive-producing areas of Greece causing devastating yield losses. Thus, initially, we have undertaken the task to identify their causal agent(s) and assess their pathogenicity and sensitivity to fungicides. The disease was identified as the olive anthracnose, and although Colletotrichum gloeosporioides and Colletotrichum acutatum species complexes are the two major causes, the obtained results confirmed that in Southern Greece the latter is the main causal agent. The obtained isolates were grouped into eight morphotypes based on their phenotypes, which differ in their sensitivities to fungicides and pathogenicity. The triazoles difenoconazole and tebuconazole were more toxic than the strobilurins being tested. Furthermore, a GC/EI/MS metabolomics model was developed for the robust chemotaxonomy of the isolates and the dissection of differences between their endo-metabolomes, which could explain the obtained phenotypes. The corresponding metabolites-biomarkers for the discrimination between morphotypes were discovered, with the most important ones being the amino acids L-tyrosine, L-phenylalanine, and L-proline, the disaccharide α,α-trehalose, and the phytotoxic pathogenesis-related metabolite hydroxyphenylacetate. These metabolites play important roles in fungal metabolism, pathogenesis, and stress responses. The study adds critical information that could be further exploited to combat olive anthracnose through its monitoring and the design of improved, customized plant protection strategies. Also, results suggest the necessity for the comprehensive mapping of the C. acutatum species complex morphotypes in order to avoid issues such as the development of fungicide-resistant genotypes.


Assuntos
Colletotrichum/fisiologia , Olea/microbiologia , Doenças das Plantas/prevenção & controle , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Colletotrichum/isolamento & purificação , Flores/microbiologia , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Grécia , Metabolômica , Azeite de Oliva , Folhas de Planta/microbiologia , Especificidade da Espécie , Virulência/efeitos dos fármacos
7.
Mol Plant Microbe Interact ; 33(7): 982-995, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32223579

RESUMO

The family Sclerotiniaceae includes important phytopathogens, such as Botrytis cinerea and Sclerotinia sclerotiorum, that activate plant immune responses to facilitate infection propagation. The mechanisms of plant resistance to these necrotrophic pathogens are still poorly understood. To discover mechanisms of resistance, we used the Ciborinia camelliae (Sclerotiniaceae)-Camellia spp. pathosystem. This fungus induces rapid infection of the blooms of susceptible cultivar Nicky Crisp (Camellia japonica × Camellia pitardii var. pitardii), while Camellia lutchuensis is highly resistant. Genome-wide analysis of gene expression in resistant plants revealed fast modulation of host transcriptional activity 6 h after ascospore inoculation. Ascospores induced the same defense pathways in the susceptible Camellia cultivar but much delayed and coinciding with disease development. We next tested the hypothesis that differences in defense timing influences disease outcome. We induced early defense in the susceptible cultivar using methyl jasmonate and this strongly reduced disease development. Conversely, delaying the response in the resistant species, by infecting it with actively growing fungal mycelium, increased susceptibility. The same plant defense pathways, therefore, contribute to both resistance and susceptibility, suggesting that defense timing is a critical factor in plant health, and resistance against necrotrophic pathogens may occur during the initial biotrophy-like stages.


Assuntos
Ascomicetos/patogenicidade , Camellia/genética , Resistência à Doença/genética , Flores/microbiologia , Doenças das Plantas/genética , Imunidade Vegetal , Acetatos , Camellia/microbiologia , Ciclopentanos , Regulação da Expressão Gênica de Plantas , Oxilipinas , Doenças das Plantas/microbiologia , Fatores de Tempo
8.
J Food Sci ; 85(4): 1151-1159, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32157694

RESUMO

Edible flowers are a new gourmet product; however, they are not always available all years. Thus, it is essential to find out technologies to guarantee this product for a longer time. Flowers of four species (borage [Borago officinalis], heartsease [Viola tricolor], kalanchoe [Kalanchoe blossfeldiana], and dandelion [Taraxacum officinale]) were subjected to freezing (in their natural form and in ice cubes) and analyzed in terms of visual appearance, the content of flavonoids, hydrolysable tannins, phenolics, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power), and microbial quality after storage for 1 and 3 months. Flowers in ice cubes showed similar appearance to fresh ones during the 3 months of storage, whereas frozen flowers were only equivalent up to 1 month with the exception of kalanchoe. Even though flowers in ice cubes showed good appearance after 3 months of storage, they had the lowest values of bioactive compounds and antioxidant activity. On the contrary, when frozen, the content of bioactive compounds maintained or even increased up to 1 month of storage compared to fresh flowers, except for borage. Furthermore, in both freezing treatments, the microorganisms' counts decreased or maintained when compared to fresh samples, except in dandelion. In general, both treatments may allow keeping the flowers after their flowering times. PRACTICAL APPLICATION: The market of edible flowers is increasing, although they are a very perishable product with short shelf-life. Edible flowers are stored in the cold (frozen or in ice cubes); however, the effect on the bioactive compounds and microbial quality that this treatment may have on borage (Borago officinalis), heartsease (Viola tricolor), kalanchoe (Kalanchoe blossfeldiana), and dandelion (Taraxacum officinale) flowers is unknown. So, the present study was conducted to increase the knowledge about the changes that freezing treatments may have in different edible flowers. The results of the present study underline that each flower has different behavior at frozen and ice cubes storage. However, freezing flowers maintain/increase the contents of bioactive compounds, while ice cubes not. Both treatments are effective in protecting flowers from microorganism growth. So, suggesting that both freezing treatments can be used as a preservative method and may allow keeping the flowers after their flowering times.


Assuntos
Antioxidantes/análise , Flores/química , Flores/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Borago/química , Borago/microbiologia , Flavonoides/análise , Análise de Alimentos , Armazenamento de Alimentos , Congelamento , Kalanchoe/química , Kalanchoe/microbiologia , Fenóis/análise , Taraxacum/química , Taraxacum/microbiologia , Viola/química , Viola/microbiologia
9.
Appl Environ Microbiol ; 86(8)2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32033956

RESUMO

The recently characterized strain Pseudomonas orientalis F9, an isolate from apple flowers in a Swiss orchard, exhibits antagonistic traits against phytopathogens. At high colonization densities, it exhibits phytotoxicity against apple flowers. P. orientalis F9 harbors biosynthesis genes for the siderophore pyoverdine as well as for the antibiotics safracin and phenazine. To elucidate the role of the three compounds in biocontrol, we screened a large random knockout library of P. orientalis F9 strains for lack of pyoverdine production or in vitro antagonism. Transposon mutants that lacked the ability for fluorescence carried transposons in pyoverdine production genes. Mutants unable to antagonize Erwinia amylovora in an in vitro double-layer assay carried transposon insertions in the safracin gene cluster. As no phenazine transposon mutant could be identified using the chosen selection criteria, we constructed a site-directed deletion mutant. Pyoverdine-, safracin-, and phenazine mutants were tested for their abilities to counteract the fire blight pathogen Erwinia amylovora ex vivo on apple flowers or the soilborne pathogen Pythium ultimum in vivo in a soil microcosm. In contrast to some in vitro assays, ex vivo and in vivo assays did not reveal significant differences between parental and mutant strains in their antagonistic activities. This suggests that, ex vivo and in vivo, other factors, such as competition for resources or space, are more important than the tested antibiotics or pyoverdine for successful antagonism of P. orientalis F9 against phytopathogens in the performed assays.IMPORTANCE Pseudomonas orientalis F9 is an antagonist of the economically important phytopathogen Erwinia amylovora, the causal agent of fire blight in pomme fruit. On King's B medium, P. orientalis F9 produces a pyoverdine siderophore and the antibiotic safracin. P. orientalis F9 transposon mutants lacking these factors fail to antagonize E. amylovora, depending on the in vitro assay. On isolated flowers and in soil microcosms, however, pyoverdine, safracin, and phenazine mutants control phytopathogens as clearly as their parental strains.


Assuntos
Agentes de Controle Biológico/química , Erwinia amylovora/fisiologia , Malus/microbiologia , Doenças das Plantas/prevenção & controle , Pseudomonas/química , Flores/microbiologia , Isoquinolinas/química , Oligopeptídeos/química , Fenazinas/química , Doenças das Plantas/microbiologia , Pseudomonas/genética
10.
Lett Appl Microbiol ; 70(4): 331-339, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32003005

RESUMO

The fructophilic bacterium Fructobacillus fructosus MCC 3996 described in the present investigation was isolated from the nectar of Butea monosperma flower and evaluated in vitro for the manifestation of probiotic features. The strain utilizes fructose faster than glucose and is capable to grow in the range of 1-35% fructose concentration (optimum 5% w/v) and thus denotes its fructophilic nature. In vitro assessments of the strain have examined for the endurance in acidic environment/gastric juice, the better auto-aggregation ability even in the presence of hydrolytic enzymes, co-aggregation with pathogenic bacteria, hydrophobicity properties and no haemolytic activity to elucidate its feasible probiotic use. The significant antagonistic activity against several detrimental bacteria, despite lacking the bacteriocin secretion, is an astonishing feature. Owing to the indigenous origin of the isolate, it could be used as a probiotic, starter culture, and/or the active ingredient of food formulation may contribute to improve the desirable fermentation, long-term storage and nutritional benefits of foods especially rich in fructose. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided in vitro evidence that Fructobacillus fructosus MCC 3996 have endurance in acidic gastric juice, better co-aggregation, auto-aggregation properties, splendid antagonistic activities against several bacteria involved in food spoilage/human infections, pertinent antibiotic susceptibility profile and no haemolytic activity. Also, F. fructosus have the capability to survive in the appreciable amount of fructose, and this advocates that the strain could be used as starter culture and/or the active ingredient of fructose-rich foods. The current in vitro study provided a strong basis for further in vivo research to identify the health beneficial characteristics of F. fructosus and its potential could be effectively utilized as health-boosting ingredient in food and pharmaceutical industries.


Assuntos
Butea/microbiologia , Leuconostocaceae/isolamento & purificação , Fermentação , Flores/microbiologia , Frutose/metabolismo , Glucose/metabolismo , Leuconostocaceae/classificação , Leuconostocaceae/genética , Leuconostocaceae/metabolismo , Filogenia , Probióticos/análise , Probióticos/classificação , Probióticos/metabolismo
11.
Yeast ; 37(4): 313-320, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32061177

RESUMO

The Wickerhamiella and Starmerella genera form a clade (W/S clade) that branches close to Yarrowia lipolytica in the Saccharomycotina species tree. It comprises approximately 90 recognized species and 50 putative new species not formally described yet. The large majority of the members of the W/S clade are ecologically associated with flowers and floricolous insects. Many species exhibit unusual metabolic traits, like fructophily and the production of sophorolipids, which are glycolipids that can be used as environmentally friendly biosurfactants. Genomic data have not only firmly established the W/S clade but have also revealed a tumultuous evolution of metabolism marked by losses and gains of important metabolic pathways, among which alcoholic fermentation. Possibly the most surprising finding brought to light by comparative genomics concerned the large number of genes acquired by some species of the W/S clade from bacteria through horizontal gene transfer, many of which were shown to be functional in their new setting. This was facilitated by the genetic tractability of one species in the clade, Starmerella bombicola, which is used for the industrial production of sophorolipids. We suggest that high-density coverage of genome sequencing in this clade, combined with the possibility to conduct molecular genetics experiments in at least one species, has the potential to set the stage for yet more exciting discoveries concerning the evolution of yeast metabolism.


Assuntos
DNA Fúngico/isolamento & purificação , Saccharomycetales/classificação , Saccharomycetales/genética , Animais , DNA Fúngico/genética , Evolução Molecular , Flores/microbiologia , Transferência Genética Horizontal , Glicolipídeos/biossíntese , Glicolipídeos/genética , Insetos/microbiologia , Redes e Vias Metabólicas , Filogenia , Saccharomycetales/isolamento & purificação
12.
Antonie Van Leeuwenhoek ; 113(3): 321-329, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31637663

RESUMO

Four yeast strains (RIFY 10001T, RIFY 10002, RIFY 10003, and RIFY 10004) were isolated from flowers growing in fields of mustard and broad beans in Japan. Ascospore formation was not observed. Sequence analysis of the D1/D2 domain of the large subunit ribosomal RNA (LSU rRNA) gene of the four strains indicated that they belong to the genus Metschnikowia and are closely related to Metschnikowia hawaiiana strain CBS 9146T and Metschnikowia orientalis strain CBS 10331T. The D1/D2 domain of the LSU rRNA gene and internal transcribed spacer regions of strain RIFY 10001T were 85.7% identical to those of M. hawaiiana strain CBS 9146T. All four strains were distinguished from the M. hawaiiana strain CBS 9146T by their inability to ferment glucose. Hence, these four strains are novel species and were named as Metschnikowia miensis (holotype: RIFY 10001T; isotypes: NBRC 112445T = CBS 14749T).


Assuntos
Flores/microbiologia , Metschnikowia/classificação , Metschnikowia/isolamento & purificação , DNA Fúngico , Japão , Metschnikowia/citologia , Metschnikowia/genética , Técnicas de Tipagem Micológica , Fenótipo , Filogenia , RNA Ribossômico
13.
Environ Microbiol ; 22(2): 646-659, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31797523

RESUMO

Rice false smut has emerged as a serious grain disease in rice production worldwide. The disease is characterized by the transformation of individual rice florets into false smut balls, which is caused by the fungal pathogen Ustilaginoidea virens. To date, little is known about the host factors required for false smut ball formation by U. virens. In this study, we identified histological determinants for the formation of false smut balls by inoculating U. virens into rice floral mutants defective with respect to individual floral parts. The results showed that U. virens could form mature false smut balls in rice floral mutants with defective pistils, but failed to develop false smut balls in the superwoman mutant lacking stamens, identifying that U. virens requires rice stamens to complete its infection cycle. Comparative transcriptome analysis indicated a list of candidate host genes that may facilitate nutrient acquisition by U. virens from the rice stamens, such as SWEET11, SWEET14 and SUT5, and genes involved in the biosynthesis of trehalose and raffinose family sugars. These data pinpoint rice stamens as the key target organ of U. virens infection and provide a valuable starting point for dissecting the molecular mechanism of false smut ball formation.


Assuntos
Flores/microbiologia , Hypocreales/crescimento & desenvolvimento , Oryza/microbiologia , Hypocreales/genética , Hypocreales/metabolismo , Proteínas de Membrana Transportadoras/genética , Doenças das Plantas/microbiologia , Rafinose/biossíntese , Transcriptoma/genética , Trealose/biossíntese
14.
ISME J ; 14(1): 245-258, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31624344

RESUMO

Bacteria colonizing the aerial parts of plants (phyllosphere) are linked to the biology of their host. They impact plant-pathogen interactions and may influence plant reproduction. Past studies have shown differences in composition and structure of the leaf, flower, and host microbiota, but an investigation of the impact of individual taxa on these variations remains to be tested. Such information will help to evaluate disparities and to better understand the biology and evolution of the plant-microbe associations. In the present study, we investigated the community structure, occupancy of host and organ, and the prevalence of phyllosphere bacteria from three host species collected at the same location. Almost all (98%) of bacterial taxa detected in the phyllosphere were not only shared across leaves and flowers, or different plant species but also had a conserved prevalence across sub-environments of the phyllosphere. We also found nonrandom associations of the phylogenetic diversity of phyllosphere bacteria. These results suggest that the phyllosphere microbiota is more conserved than previously acknowledged, and dominated by generalist bacteria adapted to environmental heterogeneity through evolutionary conserved traits.


Assuntos
Bactérias/isolamento & purificação , Plantas/microbiologia , Bactérias/classificação , Flores/microbiologia , Especificidade de Hospedeiro , Microbiota , Filogenia , Folhas de Planta/microbiologia
15.
PLoS One ; 14(12): e0225309, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31830071

RESUMO

Nectar-inhabiting microbes are increasingly appreciated as important components of plant-pollinator interactions. We quantified the incidence, abundance, diversity, and composition of bacterial and fungal communities in floral nectar of two night-blooming plants of the Sonoran Desert over the course of a flowering season: Datura wrightii (Solanaceae), which is pollinated by hawkmoths, and Agave palmeri (Agavaceae), which is pollinated by bats but visited by hawkmoths that forage for nectar. We examined the relevance of growing environment (greenhouse vs. field), time (before and after anthesis), season (from early to late in the flowering season), and flower visitors (excluded via mesh sleeves or allowed to visit flowers naturally) in shaping microbial assemblages in nectar. We isolated and identified bacteria and fungi from >300 nectar samples to estimate richness and taxonomic composition. Our results show that microbes were common in D. wrightii and A. palmeri nectar in the greenhouse but more so in field environments, both before and especially after anthesis. Bacteria were isolated more frequently than fungi. The abundance of microbes in nectar of D. wrightii peaked near the middle of the flowering season. Microbes generally were more abundant as time for floral visitation increased. The composition of bacterial and especially fungal communities differed significantly between nectars of D. wrightii and A. palmeri, opening the door to future studies examining their functional roles in shaping nectar chemistry, attractiveness, and pollinator specialization.


Assuntos
Agave/microbiologia , Datura/microbiologia , Clima Desértico , Microbiota , Arizona , Flores/microbiologia , Néctar de Plantas
16.
BMC Plant Biol ; 19(1): 532, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31791233

RESUMO

BACKGROUND: Although the most common path of infection for fire blight, a severe bacterial disease on apple, is via host plant flowers, quantitative trait loci (QTLs) for fire blight resistance to date have exclusively been mapped following shoot inoculation. It is not known whether the same mechanism underlies flower and shoot resistance. RESULTS: We report the detection of a fire blight resistance QTL following independent artificial inoculation of flowers and shoots on two F1 segregating populations derived from crossing resistant Malus ×robusta 5 (Mr5) with susceptible 'Idared' and 'Royal Gala' in experimental orchards in Germany and New Zealand, respectively. QTL mapping of phenotypic datasets from artificial flower inoculation of the 'Idared' × Mr5 population with Erwinia amylovora over several years, and of the 'Royal Gala' × Mr5 population in a single year, revealed a single major QTL controlling floral fire blight resistance on linkage group 3 (LG3) of Mr5. This QTL corresponds to the QTL on LG3 reported previously for the 'Idared' × Mr5 and an 'M9' × Mr5 population following shoot inoculation in the glasshouse. Interval mapping of phenotypic data from shoot inoculations of subsets from both flower resistance populations re-confirmed that the resistance QTL is in the same position on LG3 of Mr5 as that for flower inoculation. These results provide strong evidence that fire blight resistance in Mr5 is controlled by a major QTL on LG3, independently of the mode of infection, rootstock and environment. CONCLUSIONS: This study demonstrates for the first time that resistance to fire blight caused by Erwinia amylovora is independent of the mode of inoculation at least in Malus ×robusta 5.


Assuntos
Resistência à Doença/genética , Erwinia amylovora/fisiologia , Genes de Plantas , Ligação Genética , Malus/microbiologia , Doenças das Plantas/genética , Flores/microbiologia , Flores/fisiologia , Malus/genética , Doenças das Plantas/microbiologia , Locos de Características Quantitativas
17.
Sci Rep ; 9(1): 18006, 2019 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-31784663

RESUMO

Serratia liquefaciens strain FG3 (SlFG3), isolated from the flower of Stachytarpheta glabra in the Brazilian ferruginous fields, has distinctive genomic, adaptive, and biotechnological potential. Herein, using a combination of genomics and molecular approaches, we unlocked the evolution of the adaptive traits acquired by S1FG3, which exhibits the second largest chromosome containing the largest conjugative plasmids described for Serratia. Comparative analysis revealed the presence of 18 genomic islands and 311 unique protein families involved in distinct adaptive features. S1FG3 has a diversified repertoire of genes associated with Nonribosomal peptides (NRPs/PKS), a complete and functional cluster related to cellulose synthesis, and an extensive and functional repertoire of oxidative metabolism genes. In addition, S1FG3 possesses a complete pathway related to protocatecuate and chloroaromatic degradation, and a complete repertoire of genes related to DNA repair and protection that includes mechanisms related to UV light tolerance, redox process resistance, and a laterally acquired capacity to protect DNA using phosphorothioation. These findings summarize that SlFG3 is well-adapted to different biotic and abiotic stress situations imposed by extreme conditions associated with ferruginous fields, unlocking the impact of the lateral gene transfer to adjust the genome for extreme environments, and providing insight into the evolution of prokaryotes.


Assuntos
Aclimatação/genética , Evolução Biológica , Extremófilos/genética , Lamiales/microbiologia , Serratia liquefaciens/genética , Brasil , Ambientes Extremos , Extremófilos/isolamento & purificação , Flores/microbiologia , Genes Bacterianos , Ilhas Genômicas , Genômica , Filogenia , Plasmídeos/genética , Serratia liquefaciens/isolamento & purificação
18.
Plant Cell ; 31(12): 2947-2972, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31628167

RESUMO

Flowers are essential but vulnerable plant organs, exposed to pollinators and florivores; however, flower chemical defenses are rarely investigated. We show here that two clustered terpene synthase and cytochrome P450 encoding genes (TPS11 and CYP706A3) on chromosome 5 of Arabidopsis (Arabidopsis thaliana) are tightly coexpressed in floral tissues, upon anthesis and during floral bud development. TPS11 was previously reported to generate a blend of sesquiterpenes. By heterologous coexpression of TPS11 and CYP706A3 in yeast (Saccharomyces cerevisiae) and Nicotiana benthamiana, we demonstrate that CYP706A3 is active on TPS11 products and also further oxidizes its own primary oxidation products. Analysis of headspace and soluble metabolites in cyp706a3 and 35S:CYP706A3 mutants indicate that CYP706A3-mediated metabolism largely suppresses sesquiterpene and most monoterpene emissions from opening flowers, and generates terpene oxides that are retained in floral tissues. In flower buds, the combined expression of TPS11 and CYP706A3 also suppresses volatile emissions and generates soluble sesquiterpene oxides. Florivory assays with the Brassicaceae specialist Plutella xylostella demonstrate that insect larvae avoid feeding on buds expressing CYP706A3 and accumulating terpene oxides. Composition of the floral microbiome appears also to be modulated by CYP706A3 expression. TPS11 and CYP706A3 simultaneously evolved within Brassicaceae and form the most versatile functional gene cluster described in higher plants so far.plantcell;31/12/2947/FX1F1fx1.


Assuntos
Alquil e Aril Transferases/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Flores/metabolismo , Terpenos/antagonistas & inibidores , Alquil e Aril Transferases/genética , Animais , Arabidopsis/enzimologia , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Sistema Enzimático do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/genética , Flores/genética , Flores/microbiologia , Expressão Gênica , Larva , Microbiota , Modelos Moleculares , Simulação de Acoplamento Molecular , Monoterpenos/metabolismo , Mariposas , Família Multigênica , Filogenia , Sesquiterpenos/metabolismo , Terpenos/química , Terpenos/metabolismo , Tabaco/metabolismo , Leveduras/metabolismo
19.
Mol Ecol ; 28(23): 5155-5171, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31631452

RESUMO

Assembly of microbial communities is the result of neutral and selective processes. However, the relative importance of these processes is still debated. Microbial communities of flowers, in particular, have gained recent attention because of their potential impact to plant fitness and plant-pollinator interactions. However, the role of selection and dispersal in the assembly of these communities remains poorly understood. Here, we evaluated the role of pollinator-mediated dispersal on the contribution of neutral and selective processes in the assembly of floral microbiomes of the yellow monkeyflower (Mimulus guttatus). We sampled floral organs from flowers in the presence and absence of pollinators within five different serpentine seeps in CA and obtained 16S amplicon data on the epiphytic bacterial communities. Consistent with strong microenvironment selection within flowers we observed significant differences in community composition across floral organs and only a small effect of geographic distance. Pollinator exposure affected the contribution of environmental selection and depended on the rate and intimacy of interactions with flower visitors. This study provides evidence of the importance of dispersal and within-flower heterogeneity in shaping epiphytic bacterial communities of flowers, and highlights the complex interplay between pollinator behaviour, environmental selection and additional abiotic factors in shaping the epiphytic bacterial communities of flowers.


Assuntos
Flores/genética , Microbiota/genética , Mimulus/genética , Flores/crescimento & desenvolvimento , Flores/microbiologia , Mimulus/crescimento & desenvolvimento , Mimulus/microbiologia , Fenótipo , Polinização/genética , RNA Ribossômico 16S/genética
20.
Biol Pharm Bull ; 42(9): 1581-1589, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31474718

RESUMO

As a bacterium used in industry for production of several amino acids, an endotoxin-free Corynebacterium (C.) glutamicum is well known. However, it is also true that the endotoxin-producing other Corynebacterium species is present. An aim of this study is to obtain a lactic acid bacterium (LAB) that produces ornithine and citrulline at high levels. We successfully isolated a strain, designated K-28, and identified it as Weissella (W.) confusa. The production of ornithine and citrulline by K-28 was 18 ± 1 and 10 ± 2 g/L, respectively, with a 100 ± 9% conversion rate when arginine was continuously fed into a jar fermenter. Although the ornithine high production using C. glutamicum is industrially present, the strains have been genetically modified. In that connection, the wild-type of C. glutamicum produces only 0.5 g/L ornithine, indicating that W. confusa K-28 is superior to C. glutamicum to use a probiotic microorganism. We confirmed that W. confusa K-28 harbors an arginine deiminase (ADI) gene cluster, wkaABDCR. The production of ornithine and the expression of these genes significantly decreased under the aerobic condition rather than anaerobic one. The expression level of the five genes did not differ with or without arginine, suggesting that the production of amino acids in the K-28 strain was not induced by exogenous arginine.


Assuntos
Citrulina/biossíntese , Flores/microbiologia , Ornitina/biossíntese , Senna (Planta)/microbiologia , Weissella/metabolismo , Animais , Citrulina/toxicidade , Masculino , Ornitina/toxicidade , Probióticos , Ratos Sprague-Dawley , Ratos Wistar , Testes de Toxicidade Aguda , Weissella/isolamento & purificação
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