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1.
J Agric Food Chem ; 68(9): 2607-2614, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32096642

RESUMO

Fused-ring aromatics, important skeletal components of black carbon (BC), contribute to long-term carbon (C) sequestration in nature. They have previously been thought to be primarily formed by incomplete combustion of organic materials, whereas the nonpyrogenic origins are negligible. Using advanced solid-state 13C nuclear magnetic resonance (NMR), including recoupled long-range C-H dipolar dephasing, exchange with protonated and nonprotonated spectral editing (EXPANSE), and dipolar-dephased double-quantum/single-quantum (DQ/SQ) spectroscopy, we for the first time identify fused-ring aromatics that formed during the decomposition of wheat (Triticum sp.) straw in soil under aerobic, but not anaerobic conditions. The observed formation of polyaromatic units as plant litter decomposes provides direct evidence for humification. Moreover, the estimation of the annual flux of such nonpyrogenic BC could be equivalent to 3-12% of pyrogenic BC added to soils from all other sources. Our findings significantly extend the understanding of potential sources of fused-ring aromatic C and BC in soils as well as the global C cycle.


Assuntos
Triticum/química , Aerobiose , Bactérias/metabolismo , Biodegradação Ambiental , Caules de Planta/química , Caules de Planta/microbiologia , Microbiologia do Solo , Triticum/microbiologia
2.
Plant Dis ; 103(12): 3218-3225, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31596688

RESUMO

Basal stem rot (BSR), caused by the Ganoderma fungus, is an infectious disease that affects oil palm (Elaeis guineensis) plantations. BSR leads to a significant economic loss and reductions in yields of up to Malaysian Ringgit (RM) 1.5 billion (US$400 million) yearly. By 2020, the disease may affect ∼1.7 million tonnes of fresh fruit bunches. The plants appear symptomless in the early stages of infection, although most plants die after they are infected. Thus, early, accurate, and nondestructive disease detection is crucial to control the impact of the disease on yields. Terrestrial laser scanning (TLS) is an active remote-sensing, noncontact, cost-effective, precise, and user-friendly method. Through high-resolution scanning of a tree's dimension and morphology, TLS offers an accurate indicator for health and development. This study proposes an efficient image processing technique using point clouds obtained from TLS ground input data. A total of 40 samples (10 samples for each severity level) of oil palm trees were collected from 9-year-old trees using a ground-based laser scanner. Each tree was scanned four times at a distance of 1.5 m. The recorded laser scans were synched and merged to create a cluster of point clouds. An overhead two-dimensional image of the oil palm tree canopy was used to analyze three canopy architectures in terms of the number of pixels inside the crown (crown pixel), the degree of angle between fronds (frond angle), and the number of fronds (frond number). The results show that the crown pixel, frond angle, and frond number are significantly related and that the BSR severity levels are highly correlated (R2 = 0.76, P < 0.0001; R2 = 0.96, P < 0.0001; and R2 = 0.97, P < 0.0001, respectively). Analysis of variance followed post hoc tests by Student-Newman-Keuls (Newman-Keuls) and Dunnett for frond number presented the best results and showed that all levels were significantly different at a 5% significance level. Therefore, the earliest stage that a Ganoderma infection could be detected was mildly infected (T1). For frond angle, all post hoc tests showed consistent results, and all levels were significantly separated except for T0 and T1. By using the crown pixel parameter, healthy trees (T0) were separated from unhealthy trees (moderate infection [T2] and severe infection [T3]), although there was still some overlap with T1. Thus, Ganoderma infection could be detected as early as the T2 level by using the crown pixel and the frond angle parameters. It is hard to differentiate between T0 and T1, because during mild infection, the symptoms are highly similar. Meanwhile, T2 and T3 were placed in the same group, because they showed the same trend. This study demonstrates that the TLS is useful for detecting low-level infection as early as T1 (mild severity). TLS proved beneficial in managing oil palm plantation disease.


Assuntos
Arecaceae , Ganoderma , Arecaceae/microbiologia , Ganoderma/fisiologia , Lasers , Caules de Planta/microbiologia , Tecnologia de Sensoriamento Remoto
3.
Int. microbiol ; 22(3): 363-368, sept. 2019. graf, tab
Artigo em Inglês | IBECS | ID: ibc-184843

RESUMO

The presence of enteropathogens such as Salmonella affects the quality and safety of vegetables that are consumed in a minimally processed state. Worldwide, tomatoes are one of the main vegetables whose raw consumption has caused health alerts. As such, the aim of this study was to determine the motility and survival of Salmonella enterica subspecies enterica serovar Enteritidis on greenhouse-grown tomato plants. A completely randomized experimental design was used, and bacteria were inoculated into the substrate at the time of transplanting as well as by puncturing the plant stem, petiole, and peduncle during the vegetative, flowering, and fruiting stages. Survival was monitored throughout the production cycle; motility was evaluated separately in plant organs separated from the point of inoculation. Salmonella enteritidis survived the 120 days of the experiment both at the point of inoculation and in other organs of the tomato plant. For all treatments, there was a significant difference (P < 0.05) between bacterial counts in the root (12.45 ± 2.52 to 160 ± 4.01 CFU/g), stem (16.10 ± 2.31 to 90.55 ± 3.62 CFU/g), flower (7.0 ± 2.15 to 51.10 ± 3.80 CFU/g), and fruit (8.75 ± 2.38 to 28.2 ± 3.29 CFU/g). The results of the study indicate that Salmonella enteritidis in contact with tomato plants is a latent danger because its ability to enter, survive, and move within tomato plants until reaching the fruit, limits the effectiveness of commonly used disinfection methods, it would potentiate the risk to human health


No disponible


Assuntos
Locomoção , Lycopersicon esculentum/microbiologia , Viabilidade Microbiana , Salmonella enteritidis/fisiologia , Flores/microbiologia , Frutas/microbiologia , Raízes de Plantas/microbiologia , Fatores de Tempo , Caules de Planta/microbiologia , Carga Bacteriana
4.
Arch Microbiol ; 201(10): 1333-1349, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31309236

RESUMO

The present study aims to characterize nodule endophytic bacteria of spontaneous lupine plants regarding their diversity and their plant growth promoting (PGP) traits. The potential of PGPR inoculation was investigated to improve white lupine growth across controlled, semi-natural and field conditions. Lupinus luteus and Lupinus angustifolius nodules were shown inhabited by a large diversity of endophytes. Several endophytes harbor numerous plant growth promotion traits such as phosphates solubilization, siderophores production and 1-aminocyclopropane-1-carboxylate deaminase activity. In vivo analysis confirmed the plant growth promotion ability of two strains (Paenibacillus glycanilyticus LJ121 and Pseudomonas brenneri LJ215) in both sterilized and semi-natural conditions. Under field conditions, the co-inoculation of lupine by these strains increased shoot N content and grain yield by 25% and 36%, respectively. These two strains Paenibacillus glycanilyticus LJ121 and Pseudomonas brenneri LJ215 are effective plant growth-promoting bacteria and they may be used to develop an eco-friendly biofertilizer to boost white lupine productivity.


Assuntos
Endófitos/fisiologia , Lupinus/microbiologia , Paenibacillus/fisiologia , Raízes de Plantas/microbiologia , Pseudomonas/fisiologia , Microbiologia do Solo , Endófitos/genética , Endófitos/isolamento & purificação , Lupinus/crescimento & desenvolvimento , Desenvolvimento Vegetal , Caules de Planta/química , Caules de Planta/microbiologia , Sideróforos/metabolismo , Tunísia
5.
Bioengineered ; 10(1): 316-334, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31347943

RESUMO

In the development of medicinally important Orchidaceae, the extent of fungal endophytes specificity is not presently very clear. Limited study has been available on natural products formed and its role on plant growth, defence mechanism by endophytes, and to characterize the chief treasure of bioactive molecules. Therefore, this review article presents an evaluation of the endophytes associated with Orchidaceae for physiology, metabolism, and genomics which have prominently contributed to the resurgence of novel metabolite research increasing our considerate of multifaceted mechanisms regulatory appearance of biosynthetic gene groups encoding diverse metabolites. Additionally, we presented the comprehensive recent development of bio-strategies for the cultivation of endophytes from Orchidaceae and integration of bioengineered 'Genomics with metabolism' approaches with emphases collective omics as powerful approach to discover novel metabolite compounds. The Orchidaceae-fungal endophytes' biodynamics for sustainable development of bioproducts and its applications are supported in large-scale biosynthesis of industrially and pharmaceutical important biomolecules.


Assuntos
Produtos Biológicos/química , Endófitos/metabolismo , Fungos/metabolismo , Orchidaceae/microbiologia , Simbiose/fisiologia , Produtos Biológicos/isolamento & purificação , Endófitos/classificação , Endófitos/genética , Fungos/classificação , Fungos/genética , Redes e Vias Metabólicas/fisiologia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Metabolismo Secundário/fisiologia
6.
BMC Plant Biol ; 19(1): 319, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31311507

RESUMO

BACKGROUND: Non-host resistance (NHR) presents a compelling long-term plant protection strategy for global food security, yet the genetic basis of NHR remains poorly understood. For many diseases, including stem rust of wheat [causal organism Puccinia graminis (Pg)], NHR is largely unexplored due to the inherent challenge of developing a genetically tractable system within which the resistance segregates. The present study turns to the pathogen's alternate host, barberry (Berberis spp.), to overcome this challenge. RESULTS: In this study, an interspecific mapping population derived from a cross between Pg-resistant Berberis thunbergii (Bt) and Pg-susceptible B. vulgaris was developed to investigate the Pg-NHR exhibited by Bt. To facilitate QTL analysis and subsequent trait dissection, the first genetic linkage maps for the two parental species were constructed and a chromosome-scale reference genome for Bt was assembled (PacBio + Hi-C). QTL analysis resulted in the identification of a single 13 cM region (~ 5.1 Mbp spanning 13 physical contigs) on the short arm of Bt chromosome 3. Differential gene expression analysis, combined with sequence variation analysis between the two parental species, led to the prioritization of several candidate genes within the QTL region, some of which belong to gene families previously implicated in disease resistance. CONCLUSIONS: Foundational genetic and genomic resources developed for Berberis spp. enabled the identification and annotation of a QTL associated with Pg-NHR. Although subsequent validation and fine mapping studies are needed, this study demonstrates the feasibility of and lays the groundwork for dissecting Pg-NHR in the alternate host of one of agriculture's most devastating pathogens.


Assuntos
Basidiomycota/fisiologia , Berberis/genética , Berberis/microbiologia , Doenças das Plantas/genética , Mapeamento Cromossômico , Cromossomos de Plantas , Resistência à Doença/genética , Perfilação da Expressão Gênica , Genoma de Planta , Hibridização Genética , Padrões de Herança , Fenótipo , Doenças das Plantas/microbiologia , Caules de Planta/microbiologia , Locos de Características Quantitativas
7.
J Agric Food Chem ; 67(25): 7082-7086, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31199642

RESUMO

Vitamins are important nutrients for many fermentations, but they are generally costly. Agricultural lignocellulose biomass contains considerable amounts of vitamin B compounds, but these water-soluble vitamins are easily lost into wastewater discharge during pretreatment or detoxification of lignocellulose in biorefinery processes. Here, we showed that the dry acid pretreatment and biodetoxification process allowed the preservation of significant amounts of vitamin B, which promoted l-lactic acid fermentation efficiency significantly. Supplementation with specific vitamin B compounds, VB3 and VB5, into corn stover hydrolysate led to further increases of cellulosic l-lactic acid yield and fermentation rates. This study provided a new solution for the enhancement of biorefinery fermentation efficiency by using vitamin B compounds in lignocellulose biomass.


Assuntos
Ácido Láctico/metabolismo , Lignina/metabolismo , Pediococcus acidilactici/metabolismo , Complexo Vitamínico B/metabolismo , Fermentação , Hidrólise , Lignina/química , Pediococcus acidilactici/crescimento & desenvolvimento , Caules de Planta/química , Caules de Planta/metabolismo , Caules de Planta/microbiologia , Resíduos/análise , Zea mays/química , Zea mays/metabolismo , Zea mays/microbiologia
8.
Curr Microbiol ; 76(7): 824-834, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31020346

RESUMO

An edible gall is formed between the third and fourth nodes beneath the apical meristem near the base of Zizania latifolia shoots. This gall is harbored by and interacts with the smut fungus Ustilago esculenta. The gall is also a valuable vegetable called "white bamboo," jiaobai or gausun in China and makomotake in Japan. Five samples of the galls harvested at different stages of swelling were used to isolate microorganisms by culturing. Isolated fungal and bacterial colonies were identified by DNA sequencing and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, respectively. Several strains of U. esculenta as well as 6 other species of fungi and 10 species of bacteria were isolated. The microbiome was also evaluated by simple and outlined DNA profiling with automated rRNA intergenic spacer analysis (ARISA), and the amount of DNA of U. esculenta was determined by qPCR. At least 16 species of fungi and 40 species of bacteria were confirmed by ARISA of the overall sample. Interestingly, the greatest bacterial diversity, i.e., 18 species, was observed in the most mature sample, whereas the fungal diversity observed in this sample, i.e., 4 species, was rather poor. Based on qPCR, U. esculenta occurred in samples from all stages; however, the abundance of U. esculenta exhibited unique U-shaped relationships with growth. These results may explain why the interaction between U. esculenta and Z. latifolia also influences the unique microbial diversity observed throughout the growth stages of the swollen shoot, although the limited sample size does not allow conclusive findings.


Assuntos
Biodiversidade , Interações entre Hospedeiro e Microrganismos/fisiologia , Caules de Planta/microbiologia , Poaceae/microbiologia , Ustilago/fisiologia , Verduras/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , DNA Espaçador Ribossômico/genética , Microbiota/genética , Caules de Planta/crescimento & desenvolvimento , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA , Ustilago/classificação , Ustilago/genética , Ustilago/isolamento & purificação , Verduras/crescimento & desenvolvimento
9.
J Appl Microbiol ; 126(6): 1821-1834, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30945373

RESUMO

AIM: This study investigated the biodiversity of fungi associated with the pistachio bark beetle, Chaetoptelius vestitus, in Tunisia. We evaluated the phytopathogenic activities and tested antagonistic potentialities with respect to phytopathogens. METHODS AND RESULTS: A total of 41 fungal isolates were randomly isolated from C. vestitus adults and galleries. We identified 28 species belonging to 13 genera using ITS sequences of the ribosomal RNA operons. Pathogenicity assays performed using the excised shoot method revealed that isolates Aal_io_1 (Alternaria alternata), Feq_io_1 (Fusarium equiseti), Fgra_io_1 (Fusarium graminearum), Fve_io_1 (Fusarium verticilloides), Tro_io_1 (Trichothecium roseum) and Nqu_io_1 (Nothophoma quercina) displayed a high pathogenic activity on pistachio stems. Estimation of the antagonistic potentialities of isolated fungi against several phytopathogenic isolates as tested using a dual-culture method showed that isolates Tpi_io_1 (Talaromyces pinophilus), Pbi_io_2 (Penicillium bilaiae), Asc_io_1 (Aspergillus sclerotiorum) and Gla_io_1 (Geosmithia lavendula) displayed a broad range of antagonistic activities. CONCLUSION: Fungi associated with C. vestitus had a variable range of pathogenic activity on pistachio stem. Phytopathogenic fungi were antagonized by different fungal isolates which could be promising in pistachio protection against phytopathogenic fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first that investigated the diversity of fungi associated with C. vestitus and evaluated both their phytopathogenic activity and antagonistic potential against fungal phytopathogens.


Assuntos
Antibiose , Fungos/fisiologia , Pistacia/microbiologia , Doenças das Plantas/microbiologia , Gorgulhos/microbiologia , Animais , Técnicas de Cocultura , Fungos/classificação , Fungos/isolamento & purificação , Fungos/patogenicidade , Controle Biológico de Vetores , Caules de Planta/microbiologia , Tunísia
10.
J Agric Food Chem ; 67(19): 5486-5495, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31012315

RESUMO

Our previous research showed that Pleurotus eryngii and Pleurotus ostreatus were effective fungi for pretreatment of industrial hemp stalks to improve enzymatic saccharification. The secretomes of these two fungi were analyzed to search for the effective enzyme cocktails degrading hemp lignin during the pretreatment process. In total, 169 and 155 proteins were identified in Pleurotus eryngii and Pleurotus ostreatus, respectively, and 50% of the proteins involved in lignocellulose degradation were CAZymes. Because most of the extracellular proteins secreted by fungi are glycosylated proteins, the N-linked glycosylation of enzymes could be mapped. In total, 27 and 24 N-glycosylated peptides were detected in Pleurotus eryngii and Pleurotus ostreatus secretomes, respectively. N-Glycosylated peptides of laccase, GH92, exoglucanase, phenol oxidase, α-galactosidase, carboxylic ester hydrolase, and pectin lyase were identified. Deglycosylation could decrease enzymatic saccharification of hemp stalks. The activities of laccase, α-galactosidase, and phenol oxidase and the thermal stability of laccase were reduced after deglycosylation.


Assuntos
Cannabis/microbiologia , Proteínas Fúngicas/metabolismo , Pleurotus/enzimologia , Estabilidade Enzimática , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Galactosidases/química , Galactosidases/genética , Galactosidases/metabolismo , Glicosilação , Lacase/química , Lacase/genética , Lacase/metabolismo , Lignina/metabolismo , Monofenol Mono-Oxigenase/química , Monofenol Mono-Oxigenase/genética , Monofenol Mono-Oxigenase/metabolismo , Peroxidases/química , Peroxidases/genética , Peroxidases/metabolismo , Caules de Planta/microbiologia , Pleurotus/classificação , Pleurotus/genética , Pleurotus/crescimento & desenvolvimento , Polissacarídeo-Liase/química , Polissacarídeo-Liase/genética , Polissacarídeo-Liase/metabolismo , Transporte Proteico
11.
Plant Dis ; 103(6): 1249-1251, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30932736

RESUMO

Fusarium wilt of strawberry, caused by the soilborne pathogen Fusarium oxysporum f. sp. fragariae, is a growing threat to the strawberry industry worldwide. Symptoms of the disease typically include stunting, wilting, crown discoloration, and eventual plant death. When Fusarium wilt was discovered in California, the disease was not known to occur anywhere else in North America. Long distance movement of the pathogen would most likely occur through transport of infected plants, which seems plausible if strawberry plants can sustain infections without showing symptoms of disease. The results of this study document that F. oxysporum f. sp. fragariae can move through stolons of infected mother plants and colonize first-generation daughter plants. The pathogen can also move through stolons from first to second-generation daughter plants. Daughter plants of both generations were always symptomless. The pathogen was recovered from both roots and petioles of infected daughter plants. Similar results were obtained for two cultivars known to be susceptible to Fusarium wilt, Albion and Monterey. Transmission through stolons from mother to daughter plants also occurred in the resistant cultivar, San Andreas, but less frequently than in Albion and Monterey.


Assuntos
Fragaria , Fusarium , California , Fragaria/microbiologia , Fusarium/fisiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia
12.
Int J Syst Evol Microbiol ; 69(6): 1621-1627, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30932808

RESUMO

A novel endophytic actinomycete, designated strain RS15-1ST, was isolated from surface-sterilized stems of Oryza sativa L. collected from Sisaket province, Thailand. The colony of strain was strong orange, catalase-positive and oxidase-negative. Growth occurred at a temperature range of 17-37 °C, at pH 4.0-9.0 and in the presence of 0-13 % (w/v) NaCl. Phylogenetic analyses based on the 16S rRNA sequences showed that strain RS15-1ST belonged to the genus Gordonia and was closely related to Gordonia polyisoprenivorans DSM 44302T (98.8 %) and Gordonia rhizosphera DSM 44383T (98.4 %). The major cellular fatty acids were C16 : 0, C18 : 0 10-methyl (tbsa), C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω9c. The menaquinones were MK-9(H2) and MK-8(H2). Strain RS15-1ST contained meso-diaminopimelic acid, arabinose, galactose, mannose and ribose in whole-cell hydrolysates. The polar lipids of the strain were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, an unidentified polar lipid and two unidentified phospholipids. The DNA G+C content was 66.3 mol%. In silico DNA-DNA hybridization of strain RS15-1ST showed 48.3 and 20.5 % relatedness to its closest neighbours, Gordonia polyisoprenivorans DSM 44302T and Gordonia rhizosphera DSM 44383T, respectively. Based on data of genotypic, phenotypic, phylogenetic and chemotaxonomic analysis, strain RS15-1ST represents a novel species of the genus Gordonia, for which the name Gordonia oryzae sp. nov. is proposed. The type strain is RS15-1ST (=TBRC 8485T=NBRC 113446T).


Assuntos
Gordonia (Bactéria)/classificação , Oryza/microbiologia , Filogenia , Caules de Planta/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Gordonia (Bactéria)/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tailândia , Vitamina K 2/química
13.
Fungal Biol ; 123(4): 330-340, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30928041

RESUMO

The fungus Trichoderma reesei is employed in the production of most enzyme cocktails used by the lignocellulosic biofuels industry today. Despite significant improvements, the cost of the required enzyme preparations remains high, representing a major obstacle for the industrial production of these alternative fuels. In this study, a new Trichoderma erinaceum strain was isolated from decaying sugarcane straw. The enzyme cocktail secreted by the new isolate during growth in pretreated sugarcane straw-containing medium presented higher specific activities of ß-glucosidase, endoxylanase, ß-xylosidase and α-galactosidase than the cocktail of a wild T. reesei strain and yielded more glucose in the hydrolysis of pretreated sugarcane straw. A proteomic analysis of the two strains' secretomes identified a total of 86 proteins, of which 48 were exclusive to T. erinaceum, 35 were exclusive to T. reesei and only 3 were common to both strains. The secretome of T. erinaceum also displayed a higher number of carbohydrate-active enzymes than that of T. reesei (37 and 27 enzymes, respectively). Altogether, these results reveal the significant potential of the T. erinaceum species for the production of lignocellulases, both as a possible source of enzymes for the supplementation of industrial cocktails and as a candidate chassis for enzyme production.


Assuntos
Proteínas Fúngicas/análise , Lignina/metabolismo , Caules de Planta/microbiologia , Proteoma/análise , Saccharum/microbiologia , Trichoderma/isolamento & purificação , Trichoderma/metabolismo , Biotransformação , Hidrolases/análise , Hidrólise , Trichoderma/química
14.
Braz J Microbiol ; 50(2): 481-494, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30877665

RESUMO

Fusarium crown and root rot (FCRR), caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL), is a soilborne tomato disease of increased importance worldwide. In this study, Withania somnifera was used as a potential source of biological control and growth-promoting agents. Seven fungal isolates naturally associated with W. somnifera were able to colonize tomato seedlings. They were applied as conidial suspensions or a cell-free culture filtrate. All isolates enhanced treated tomato growth parameters by 21.5-90.3% over FORL-free control and by 27.6-93.5% over pathogen-inoculated control. All tested isolates significantly decreased by 28.5-86.4% disease severity over FORL-inoculated control. The highest disease suppression, by 86.4-92.8% over control and by 81.3-88.8% over hymexazol-treated control, was achieved by the I6 isolate. FORL radial growth was suppressed by 58.5-82.3% versus control when dual cultured with tested isolates and by 61.8-83.2% using their cell-free culture filtrates. The most active agent was identified as Fusarium sp. I6 (MG835371), which displayed chitinolytic, proteolytic, and amylase activities. This has been the first report on the potential use of fungi naturally associated with W. somnifera for FCRR suppression and for tomato growth promotion. Further investigations are required in regard to mechanisms of action involved in disease suppression and plant growth promotion.


Assuntos
Antifúngicos/metabolismo , Agentes de Controle Biológico/metabolismo , Endófitos/metabolismo , Fusarium/crescimento & desenvolvimento , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/microbiologia , Doenças das Plantas/prevenção & controle , Withania/microbiologia , Amilases/metabolismo , Quitinases/metabolismo , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Proteólise
15.
Mol Plant ; 12(3): 360-373, 2019 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-30853061

RESUMO

To optimize fitness, plants must efficiently allocate their resources between growth and defense. Although phytohormone crosstalk has emerged as a major player in balancing growth and defense, the genetic basis by which plants manage this balance remains elusive. We previously identified a quantitative disease-resistance locus, qRfg2, in maize (Zea mays) that protects against the fungal disease Gibberella stalk rot. Here, through map-based cloning, we demonstrate that the causal gene at qRfg2 is ZmAuxRP1, which encodes a plastid stroma-localized auxin-regulated protein. ZmAuxRP1 responded quickly to pathogen challenge with a rapid yet transient reduction in expression that led to arrested root growth but enhanced resistance to Gibberella stalk rot and Fusarium ear rot. ZmAuxRP1 was shown to promote the biosynthesis of indole-3-acetic acid (IAA), while suppressing the formation of benzoxazinoid defense compounds. ZmAuxRP1 presumably acts as a resource regulator modulating indole-3-glycerol phosphate and/or indole flux at the branch point between the IAA and benzoxazinoid biosynthetic pathways. The concerted interplay between IAA and benzoxazinoids can regulate the growth-defense balance in a timely and efficient manner to optimize plant fitness.


Assuntos
Resistência à Doença , Ácidos Indolacéticos/imunologia , Doenças das Plantas/imunologia , Proteínas de Plantas/imunologia , Raízes de Plantas/crescimento & desenvolvimento , Caules de Planta/microbiologia , Zea mays/imunologia , Fusarium/fisiologia , Gibberella/fisiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/imunologia , Proteínas de Plantas/genética , Raízes de Plantas/imunologia , Caules de Planta/genética , Caules de Planta/imunologia , Zea mays/genética , Zea mays/microbiologia
16.
J Sci Food Agric ; 99(8): 4054-4062, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30737799

RESUMO

BACKGROUND: White rot fungi have been used to improve the nutritive value of lignocellulose for ruminants. In feed analysis, the Van Soest method is widely used to determine the cell wall contents. To assess the reliability of this method (Method A) for determination of cell wall contents in fungal-treated wheat straw, we compared a combined monosaccharide analysis and pyrolysis coupled to gas chromatography with mass spectrometry (Py-GC/MS) (Method B). Ruminal digestibility, measured as in vitro gas production (IVGP), was subsequently used to examine which method explains best the effect of fungal pretreatment on the digestibility of wheat straw. RESULTS: Both methods differed considerably in the mass recoveries of the individual cell wall components, which changed on how we assess their degradation characteristics. For example, Method B gave a higher degradation of lignin (61.9%), as compared to Method A (33.2%). Method A, however, showed a better correlation of IVGP with the ratio of lignin to total structural carbohydrates, as compared to Method B (Pearson's r of -0.84 versus -0.69). Nevertheless, Method B provides a more accurate quantification of lignin, reflecting its actual modification and degradation. With the information on the lignin structural features, Method B presents a substantial advantage in understanding the underlying mechanisms of lignin breakdown. Both methods, however, could not accurately quantify the cellulose contents - among others, due to interference of fungal biomass. CONCLUSION: Method A only accounts for the recalcitrant residue and therefore is more suitable for evaluating ruminal digestibility. Method B allows a more accurate quantification of cell wall, required to understand and better explains the actual modification of the cell wall. The suitability of both methods, therefore, depends on their intended purposes. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Ração Animal/análise , Basidiomycota/metabolismo , Parede Celular/química , Triticum/microbiologia , Ração Animal/microbiologia , Animais , Parede Celular/metabolismo , Parede Celular/microbiologia , Celulose/análise , Celulose/metabolismo , Digestão , Cromatografia Gasosa-Espectrometria de Massas , Lignina/análise , Lignina/metabolismo , Valor Nutritivo , Caules de Planta/química , Caules de Planta/metabolismo , Caules de Planta/microbiologia , Ruminantes , Triticum/química , Triticum/metabolismo
17.
Int Microbiol ; 22(2): 191-201, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30810983

RESUMO

In this study, endophytic bacteria isolated from root, stem, and leaf tissues of stripe rust-susceptible (Inqilab 91, Galaxy 2013, and 15BT023) and stripe rust-resistant (NARC 2011, Ujala 2015, TW1410) cultivars were identified and characterized. Abundance of endophytes was found in roots as compared with stems and leaves. Resistant and susceptible cultivars significantly differed in abundance of endophytic bacteria. Restriction analysis of 16S rRNA genes amplified from 100 bacterial isolates produced 17 unique patterns. Representatives of each of the 17 unique patterns were sequenced and identified. Among the sequenced bacteria, 8 belonged to Firmicutes, 7 were Proteobacteria, and 2 were Actinobacteria. Most of the isolates have plant growth-promoting properties and a few have the potential of producing hydrolytic enzymes. Two isolates showed significant inhibition of rust spore germination. These endophytic bacteria not only can be helpful in growth-promoting activities but also can assist in biocontrol of stripe rust disease.


Assuntos
Bactérias/classificação , Bactérias/isolamento & purificação , Biota , Endófitos/classificação , Endófitos/isolamento & purificação , Doenças das Plantas/microbiologia , Triticum/microbiologia , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Resistência à Doença , Endófitos/genética , Endófitos/crescimento & desenvolvimento , Filogenia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
18.
Int Microbiol ; 22(3): 363-368, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30811003

RESUMO

The presence of enteropathogens such as Salmonella affects the quality and safety of vegetables that are consumed in a minimally processed state. Worldwide, tomatoes are one of the main vegetables whose raw consumption has caused health alerts. As such, the aim of this study was to determine the motility and survival of Salmonella enterica subspecies enterica serovar Enteritidis on greenhouse-grown tomato plants. A completely randomized experimental design was used, and bacteria were inoculated into the substrate at the time of transplanting as well as by puncturing the plant stem, petiole, and peduncle during the vegetative, flowering, and fruiting stages. Survival was monitored throughout the production cycle; motility was evaluated separately in plant organs separated from the point of inoculation. Salmonella enteritidis survived the 120 days of the experiment both at the point of inoculation and in other organs of the tomato plant. For all treatments, there was a significant difference (P < 0.05) between bacterial counts in the root (12.45 ± 2.52 to 160 ± 4.01 CFU/g), stem (16.10 ± 2.31 to 90.55 ± 3.62 CFU/g), flower (7.0 ± 2.15 to 51.10 ± 3.80 CFU/g), and fruit (8.75 ± 2.38 to 28.2 ± 3.29 CFU/g). The results of the study indicate that Salmonella enteritidis in contact with tomato plants is a latent danger because its ability to enter, survive, and move within tomato plants until reaching the fruit, limits the effectiveness of commonly used disinfection methods, it would potentiate the risk to human health.


Assuntos
Locomoção , Lycopersicon esculentum/microbiologia , Viabilidade Microbiana , Salmonella enteritidis/fisiologia , Carga Bacteriana , Flores/microbiologia , Frutas/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Fatores de Tempo
19.
Microbes Environ ; 34(1): 59-63, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30726788

RESUMO

Vitex rotundifolia L. f. (Lamiaceae), which commonly grows at sand coasts, is important for coast protection and the prevention of erosion. However, the diversity and roles of fungi associated with this plant remain unclear. A total of 1,052 endophytic isolates from 1,782 plants tissues from two sand beaches in northern Taiwan were classified into 76 morphospecies based on culture morphology and ITS or LSU rRNA gene sequence comparisons. Critical species were further identified using protein gene sequences and microscopy. Most of the isolates at both sites belonged to the phylum Ascomycota, with Pleosporales having the most species (15 species). The largest number of isolates (47.7%) was from the stems, followed by the roots (22.5%), leaves (16.6%), and branches (13.1%). The three species with the highest isolation frequencies at both sites were Alternaria alternata, Aspergillus terreus, and an undescribed species of Alpestrisphaeria. A. terreus was found in all organs. A. alternata was detected in all organs, except the roots. Alpestrisphaeria sp. was only found in the roots and stems. In the stems and roots, strain numbers from cortical tissues were approximately two-fold higher than those from the corresponding woody tissue. The overall colonization rate in the stems was significantly higher than those that in the roots and leaves. The majority of fungi appeared to be saprobes, which may play important roles in nutrient recycling during sand burial and mediate further stress factors in the coastal habitat.


Assuntos
Biodiversidade , Endófitos/isolamento & purificação , Fungos/isolamento & purificação , Vitex/microbiologia , DNA Fúngico/genética , DNA Ribossômico/genética , Endófitos/classificação , Endófitos/genética , Endófitos/crescimento & desenvolvimento , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Genoma Fúngico/genética , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Plantas Tolerantes a Sal/microbiologia , Taiwan
20.
J Gen Appl Microbiol ; 65(4): 209-213, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-30726794

RESUMO

Azorhizobium caulinodans, a kind of rhizobia, has a reb operon encoding pathogenic R-body components, whose expression is usually repressed by a transcription factor PraR. Mutation on praR induced a high expression of reb operon and the formation of aberrant nodules, in which both morphologically normal and shrunken host cells were observed. Histochemical GUS analyses of praR mutant expressing reb operon-uidA fusion revealed that the bacterial cells within the normal host cells highly expressed the reb operon, but rarely produced R-bodies. On the other hand, the bacterial cells within the shrunken host cells frequently produced R-bodies but rarely expressed the reb operon. This suggests that R-body production is not only regulated at the transcriptional level, but by other regulatory mechanisms as well.


Assuntos
Azorhizobium caulinodans/genética , Proteínas de Bactérias/genética , Deleção de Genes , Óperon , Caules de Planta/microbiologia , Regulação Bacteriana da Expressão Gênica , Mutação , Fixação de Nitrogênio , Sesbania/microbiologia , Simbiose , Fatores de Transcrição/genética
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