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1.
Pestic Biochem Physiol ; 158: 149-155, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378351

RESUMO

Induced resistance is an effective measure for controlling plant diseases by utilizing the natural defense of the host and meets the strategic needs of pesticide application and safety for agricultural products worldwide. Ganoderma lucidum polysaccharide (GLP), which is the main active molecule of G. lucidum, has been widely used in functional food and clinical medicine. However, there are few reports of the use of GLP for the prevention and control of plant diseases. The purpose of this study is to explore the effect of GLP and its mechanism of inducing plant resistance. In this study, we found that GLP spray and irrigation root treatments can promote growth in cotton. After soaking in GLP, theseedling height and cotton fusarium wilt resistance both increased to some extent, effects that were dose dependent. After treatment of cotton with GLP, the activities of peroxidase (POD), superoxide dismutase (SOD) and polyphenol oxidase (PPO) in leaves increased significantly, whereas the content of malondialdehyde (MDA) decreased. In addition, QRT-PCR results showed significantly increased relative expression of genes related to the jasmonic acid pathway in cotton. Therefore, we speculate that GLP can induce plant resistance by stimulating the jasmonate pathway.


Assuntos
Fusarium/efeitos dos fármacos , Gossypium/microbiologia , Polissacarídeos/farmacologia , Reishi/química , Antioxidantes/metabolismo , Gossypium/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Doenças das Plantas/microbiologia , Polissacarídeos/química , Superóxido Dismutase/metabolismo
2.
Int J Syst Evol Microbiol ; 69(8): 2506-2513, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31204971

RESUMO

A Gram-stain-positive and catalase negative coccus, designated strain Gos25-1T, isolated from a cotton flower (Gossypium hirsutum L.) collected from Khao Wong district, Kalasin province, Thailand. The taxonomic position of this strain was systematically studied based upon polyphasic taxonomic methods. The strain was facultatively anaerobic and produced l-lactic acid from glucose. The predominant cellular fatty acids were the straight-chain fatty acids C18 : 1ω9c and C16 : 0. According to 16S rRNA and phenylalanyl-tRNA synthase alpha subunit (pheS) gene sequence similarity, this strain was closely related to Enterococcus pallens NBRC 100697T, E. hermanniensis CIP 108559T, E. avium NBRC 100477T and E. raffinosus NBRC 100492T with 98.9-99.1 % and 77.0-82.0 % sequence similarities, respectively. Phylogenetic analysis indicated that strain Gos25-1T was clearly distinguished from closely related species of the genus Enterococcus. Draft genome of Gos25-1T had a size of 3.99 Mb which was contained 3788 coding sequences with in silico G+C content of 42.4 mol%. The ANIb and a digital DNA-DNA hybridisation (dDDH) values between strain Gos25-1T and the closest related species, E. pallens NBRC 100697T were 73.65 and 21.10 %, respectively. According to polyphasic characterisation, this strain represents a novel species of the genus Enterococcus, for which the name Enterococcus florum sp. nov. is proposed. The type strain is Gos25-1T (=CIP 110956T=LMG 29007T=NBRC 111461T=TISTR 2382T).


Assuntos
Enterococcus/classificação , Flores/microbiologia , Gossypium/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Enterococcus/isolamento & purificação , Ácidos Graxos/química , Genes Bacterianos , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tailândia
3.
IET Nanobiotechnol ; 13(2): 219-225, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051454

RESUMO

Silver nanoparticles (Ag NPs) were synthesised using the crude ethyl acetate extracts of Ulva lactuca and evaluated their bioefficacy against two crop-damaging pathogens. The sets of lattice planes in the XRD spectrum for the Ag NPs were indexed to the 111, 200, 220 and 311 orientations and support the crystalline nature of the Ag NPs. The 3414 and 2968 cm-1 peaks were observed in crude algal thallus extract and they were characteristic of terpenoids. Further, a peak at 1389 cm-1 was observed as fatty acids. The marine macroalgae terpenoids and palmitic acid acted as reducing agent and stabiliser, respectively. The size (3 and 50 nm) and shape (spherical) of Ag NPs were recorded. The energy-dispersive X-ray spectroscopy analysis exemplified the presence of silver in its elemental nature. Moreover, U. lactuca Ag NPs were effective against two cotton phytopathogens namely Fusarium oxysporum f.sp. vasinfectum (FOV) and Xanthomonas campestris pv. malvacearum (XAM). The minimum inhibitory concentration was found to be 80.0 and 43.33 µg ml-1 against FOV and XAM, respectively. Results confirmed the anti-microbial activity of green nanoparticles against select pathogens and suggest their possible usage in developing antifungal agents for controlling destructive pathogens in a cotton agroecosystem.


Assuntos
Gossypium/microbiologia , Nanopartículas Metálicas/química , Doenças das Plantas/prevenção & controle , Alga Marinha/química , Prata/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Fusarium/efeitos dos fármacos , Química Verde/métodos , Tamanho da Partícula , Doenças das Plantas/microbiologia , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Ulva/química
4.
Plant Dis ; 103(7): 1595-1604, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31059384

RESUMO

Alternaria leaf spot (caused by Alternaria spp.) is one of the most common foliar diseases of cotton (Gossypium spp.) and occurs in most cotton-growing regions of the world. In surveys of commercial cotton fields, Alternaria leaf spot has increased in prevalence and incidence in southern New Mexico due to favorable environmental conditions in recent years. Incidence, severity, and etiology of leaf spot of cotton in southern New Mexico were determined. Fourteen cotton fields with plants exhibiting leaf spot symptoms were evaluated in October and November 2016, when plants were at late growth stage. Disease incidence was 100% in 13 of the fields, and averaged 70% in the 14th field. Average disease severity index for all fields ranged from 21.5 to 87.0. For identification of the causal agent, 14 isolates (one from each field) were characterized based on morphological features and PCR using universal primers ITS4/ITS5 and primers targeting the plasma membrane ATPase gene. Colonies of all 14 isolates were olive green with distinct white margins and relatively small spores when compared with reference isolates of large-spored species. All 14 isolates were identified as A. alternata. The fungus grew on potato dextrose agar from 5 to 35°C, and optimum growth occurred at temperatures between 20 and 30°C. Cotton plants inoculated with selected isolates of A. alternata displayed symptoms similar to those observed under field conditions. This is the first report of A. alternata as a causal agent of Alternaria leaf spot on cotton in southern New Mexico.


Assuntos
Alternaria , Gossypium , Alternaria/genética , Alternaria/fisiologia , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Gossypium/microbiologia , New Mexico , Doenças das Plantas/microbiologia
5.
J Agric Food Chem ; 67(24): 6828-6836, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31136163

RESUMO

Verticillium wilt, caused by Verticillium dahliae, results in a dramatic loss of cotton yields in China. There is great potential for biocontrol to manage this destructive crop disease. In this study, we obtained the endophytic bacterium Bacillus halotolerans Y6 from Verticillium wilt-resistant cotton Gossypium barbadense Xinhai15; this bacterium possesses strong antagonistic abilities that inhibit V. dahliae spore germination and mycelial growth. The results of the enzyme activity assay, heterologous expression, and gene knockdown showed that the key virulence factor of Y6 for antagonizing V. dahliae was ß -glucanase Bgy6. To facilitate field tests of biological control, we constructed the homologous Bgy6-overexpression strain OY6. Compared with the wild-type Y6 strain, the ß-glucanase activity of OY6 was increased by 91.79%, and the inhibition rate of OY6 against V. dahliae V991 exceeded 96.7%. Moreover, the spores of V. dahliae V991 treated with OY6 showed more mucus and larger holes on the surface, as observed by scanning electron microscopy. Potting test results illustrated that both OY6 and Y6 could improve the resistance of upland cotton to Verticillium wilt. With the inoculation of V. dahliae V991 for 45 days, the disease index of G. hirsutum TM-1 treated with OY6 was only 8.33, which was significantly lower than that in plants treated with the wild-type strain Y6 (17.86) or the controls without bacteria (35.94). Our research provides a new idea for the control of Verticillium wilt in upland cotton via transforming endophytic bacteria of Verticillium wilt-resistant cotton and proposes a new solution to prevent and control Verticillium wilt.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/genética , Endo-1,3(4)-beta-Glucanase/genética , Endófitos/enzimologia , Gossypium/microbiologia , Doenças das Plantas/imunologia , Verticillium/fisiologia , Fatores de Virulência/genética , Antibiose , Bacillus/genética , Bacillus/isolamento & purificação , Bacillus/fisiologia , Proteínas de Bactérias/metabolismo , Resistência à Doença , Endo-1,3(4)-beta-Glucanase/metabolismo , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/fisiologia , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Gossypium/imunologia , Doenças das Plantas/microbiologia , Fatores de Virulência/imunologia
6.
Plant Sci ; 284: 127-134, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31084865

RESUMO

Avr9/Cf-9-INDUCED F-BOX1 (ACIF1) was first identified during screening of Avr9/Cf-9-elicited genes in tobacco. Further analysis revealed that ACIF1 was required for hypersensitive responses triggered by various elicitors in tobacco and tomato, indicating that it may be involved in various disease resistance. Here, we cloned its cotton (Gossypium hirsutum) homolog GhACIF1, which encodes an F-box protein. We show that GhACIF1 interacts with the putative SKP1-like protein, named GhSKP1. Disease resistance assays show that GhACIF1 enhances resistance to Verticillium dahliae in Arabidopsis plants, while silencing of GhACIF1 confers sensitivity to V. dahliae in cotton. Further analysis show that PevD1 elicitor activates hypersensitive and acquired immune response mediated by GhACIF1. Collectively, these results indicate that GhACIF1 contributes to protection against V. dahliae infection.


Assuntos
Resistência à Doença , Proteínas F-Box/fisiologia , Gossypium/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/fisiologia , Verticillium , Resistência à Doença/fisiologia , Proteínas F-Box/genética , Inativação Gênica , Gossypium/genética , Gossypium/microbiologia , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Técnicas do Sistema de Duplo-Híbrido , Verticillium/metabolismo
7.
J Basic Microbiol ; 59(6): 632-644, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30900762

RESUMO

Microbial biofilms are gaining importance in agriculture, due to their multifaceted agronomic benefits and resilience to environmental fluctuations. This study focuses on comparing the influence of single inoculation-Azotobacter chroococcum (Az) or Trichoderma viride (Tv) and their biofilm (Tv-Az), on soil and plant metabolic activities in wheat and cotton grown under Phytotron conditions. Tv-Az proved superior to all the other treatments in terms of better colonisation, plant growth attributes and 10-40% enhanced availability of macronutrients and micronutrients in the soil, over control. Confocal and scanning electron microscopy showed that the cells attached to the root tips initially, followed by their proliferation along the surface of the roots. Soil polysaccharides, proteins and dehydrogenase activity showed several fold enhancement in Tv-Az biofilm inoculated samples. Time course studies revealed that the population of Az and Tv in the rhizoplane and rhizosphere was significantly higher with a 0.14-0.31 log colony-forming unit (CFU) increase in the biofilm-inoculated treatment in both crops. Enhancement in soil biological activities was facilitated by the improved colonisation of the biofilm, due to the synergistic association between Tv and Az. This demonstrates the utility of Tv-Az biofilm as a multifunctional plant growth promoting and soil fertility enhancing option in agriculture.


Assuntos
Azotobacter/fisiologia , Biofilmes/crescimento & desenvolvimento , Gossypium/crescimento & desenvolvimento , Nutrientes/análise , Solo/química , Trichoderma/fisiologia , Triticum/crescimento & desenvolvimento , Inoculantes Agrícolas/crescimento & desenvolvimento , Inoculantes Agrícolas/fisiologia , Disponibilidade Biológica , Gossypium/microbiologia , Nutrientes/farmacocinética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Rizosfera , Microbiologia do Solo , Triticum/microbiologia
8.
Transgenic Res ; 28(2): 199-212, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30790127

RESUMO

Transgenic cotton expressing the toxin Cry1Ac from Bacillus thuringiensis L. (Bt) is widely cultivated in Pakistan after its formal approval in 2010. The exposure of the local target pests to the Cry1Ac endotoxin for this duration might have changed the baseline susceptibility. To probe the status of resistance in one of the main target pests, Helicoverpa armigera, field-collected larvae were reared in the lab for conducting leaf fed bioassays. Twenty-six cotton accessions collected from farmers, including 25 Bt-cotton and one non-Bt, were tested to quantify the level of Cry1Ac, an insecticidal crystalline protein (ICP), in leaves of lower, middle and upper canopies of plants. The concentration of ICP was tested through Enzyme-linked Immunosorbent Assay and found significantly variable (P < 0.01) between and within accessions. The highest mean expression was observed in Accession-2 and Accession-4, while the lowest in Accession-21 and Accession-19. Among fresh leaf tissues from different parts of the plant, the highest mean expression was recorded at 60 days after sowing in upper canopy leaves of cotton accessions, which decreased in lower parts of the plant with the lowest mean expression in lower canopy leaves. Laboratory bioassays, to calculate lethal dose, for H. armigera showed that LD50 and LD95 were 0.62 µg/g and 1.59 µg/g of fresh tissue weight, respectively. A strong positive correlation also exists between the levels of Cry1Ac protein and insect mortality (r = 0.84). These findings suggested the future risk of cultivation of Bt cotton, carrying single Cry1Ac gene, in Pakistan, as resistance surging in H. armigera against Cry protein. These results may also have significant implications for the resistance management in Bt crops, especially cotton, in future.


Assuntos
Bacillus thuringiensis/patogenicidade , Proteínas de Bactérias/toxicidade , Endotoxinas/toxicidade , Gossypium/microbiologia , Proteínas Hemolisinas/toxicidade , Resistência a Inseticidas , Inseticidas/toxicidade , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores , Animais , Proteínas de Bactérias/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Mariposas/efeitos dos fármacos , Mariposas/microbiologia , Paquistão , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia
9.
BMC Plant Biol ; 19(1): 19, 2019 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-30634907

RESUMO

BACKGROUND: Verticillium wilt (VW), also known as "cotton cancer," is one of the most destructive diseases in global cotton production that seriously impacts fiber yield and quality. Despite numerous attempts, little significant progress has been made in improving the VW resistance of upland cotton. The development of chromosome segment substitution lines (CSSLs) from Gossypium hirsutum × G. barbadense has emerged as a means of simultaneously developing new cotton varieties with high-yield, superior fiber, and resistance to VW. RESULTS: In this study, VW-resistant investigations were first conducted in an artificial greenhouse, a natural field, and diseased nursery conditions, resulting in the identification of one stably VW-resistant CSSL, MBI8255, and one VW-susceptible G. hirsutum, CCRI36, which were subsequently subjected to biochemical tests and transcriptome sequencing during V991 infection (0, 1, and 2 days after inoculation). Eighteen root samples with three replications were collected to perform multiple comparisons of enzyme activity and biochemical substance contents. The findings indicated that VW resistance was positively correlated with peroxidase and polyphenol oxidase activity, but negatively correlated with malondialdehyde content. Additionally, RNA sequencing was used for the same root samples, resulting in a total of 77,412 genes, of which 23,180 differentially expressed genes were identified from multiple comparisons between samples. After Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis on the expression profiles identified using Short Time-series Expression Miner, we found that the metabolic process in the biological process, as well as the pathways of phenylpropanoid biosynthesis and plant hormone signal transduction, participated significantly in the response to VW. Gene functional annotation and expression quantity analysis indicated the important roles of the phenylpropanoid metabolic pathway and oxidation-reduction process in response to VW, which also provided plenty of candidate genes related to plant resistance. CONCLUSIONS: This study concentrates on the preliminary response to V991 infection by comparing the VW-resistant CSSL and its VW-susceptible recurrent parent. Not only do our findings facilitate the culturing of new resistant varieties with high yield and superior performance, but they also broaden our understanding of the mechanisms of cotton resistance to VW.


Assuntos
Cromossomos de Plantas/genética , Gossypium/genética , Gossypium/microbiologia , Transcriptoma/genética , Verticillium/patogenicidade , Regulação da Expressão Gênica de Plantas/genética
10.
Plant Dis ; 103(3): 422-429, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30632895

RESUMO

Bacterial blight, historically a seed-borne disease of cotton (Gossypium hirsutum) is caused by Xanthomonas citri pv. malvacearum, resulted in significant economic losses prior to development of resistant varieties and implementation of acid-delinting of planting seed. Periodic outbreaks have been associated with seed since the early twentieth century; of note, the disease has experienced a resurgence since 2011. Effective management of bacterial blight is dependent on accurate diagnosis and detection of the pathogen. Currently, detection of X. citri pv. malvacearum is performed by time-consuming microbiological methods. In this study, a novel and sensitive TaqMan-based qPCR protocol was developed to test for X. citri pv. malvacearum in cotton plant tissue. The primers developed are specific to five races of X. citri pv. malvacearum, but not to other Xanthomonas species or cotton-associated nonpathogenic bacteria. The efficiency of this assay was evaluated on artificially inoculated cotton leaves and seed, on naturally infected cotton leaves, and on bolls and seed originating from bacterial blight symptomatic bolls. The protocol's efficiency from artificially inoculated plant tissue was 102 copies g-1 and 37 copies from 1 g seed for leaves and seed, respectively. In addition, X. citri pv. malvacearum was detected from 94% of the seed samples originating from blight symptomatic bolls. The qPCR protocol provides a rapid and accurate method for diagnosis and detection of bacterial blight and offers a tool for monitoring X. citri pv. malvacearum and potentially reducing its spread in seed.


Assuntos
Técnicas Microbiológicas/métodos , Reação em Cadeia da Polimerase em Tempo Real , Xanthomonas , Gossypium/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Sementes/microbiologia , Xanthomonas/genética
11.
Int J Mol Sci ; 19(12)2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30545043

RESUMO

The homeodomain-leucine zipper (HD-ZIP) is a plant-specific transcription factor family that plays important roles in plant developmental processes in response to multiple stressors. We previously isolated a cotton HD-ZIP class I transcription factor gene, GhHB12, which is regulated by the circadian clock and photoperiodism. Furthermore, it regulates cotton architecture, phase transition, and photoperiod sensitivity. Here we report that GhHB12 was induced by methyl jasmonate (MeJA) and Verticillium dahliae infection. Additionally, stress-responsive elements were found in the GhHB12 promoter. Promoter fusion analysis showed that GhHB12 was predominantly expressed in primary roots and that it was induced by mechanical damage. Overexpression of GhHB12 increased susceptibility of the cotton plant to the fungal pathogens Botrytis cinerea and V. dahliae, which was coupled with suppression of the jasmonic acid (JA)-response genes GhJAZ2 and GhPR3. Our results suggest that GhHB12, a cotton stress-responsive HD-ZIP I transcription factor, negatively regulates cotton resistance to V. dahliae by suppressing JA-response genes.


Assuntos
Resistência à Doença , Gossypium/imunologia , Gossypium/microbiologia , Proteínas de Homeodomínio/metabolismo , Doenças das Plantas/microbiologia , Fatores de Transcrição/metabolismo , Verticillium/fisiologia , Acetatos/farmacologia , Botrytis/efeitos dos fármacos , Botrytis/fisiologia , Ciclopentanos/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Glucuronidase/metabolismo , Gossypium/genética , Proteínas de Homeodomínio/genética , Oxilipinas/farmacologia , Doenças das Plantas/genética , Plantas Geneticamente Modificadas , Fatores de Transcrição/genética , Verticillium/efeitos dos fármacos
12.
Ecotoxicol Environ Saf ; 164: 618-628, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30165339

RESUMO

Understanding the community structure of soil microbes is required to evaluate the potential effects of genetically modified (GM) plants on ecological environments. Bacterial communities in soil planted with conventional cotton (CC) and transgenic cultivar (TC) in a natural ecosystem for three years were characterized by 454 pyrosequencing of the V3-V5 and V5-V9 regions of 16S rDNA from June to September 2013. V3-V5 and V5-V9 regions yielded a total of 12,848 and 10,541 OTUs, respectively. The V5-V9 amplicon was additionally used to detect phyla that were poorly sequenced by V3-V5 (such as Chlamydiae, Crenarchaeota and Archaea). Among the species detected by each primer pair, 46% of the species identified from V3-V5 and 60% of those identified from V5-V9 were detected by both primer pairs. Although distinct bacterial compositions existed between the two amplified regions, statistical analysis revealed no significant difference in the diversity indexes or phylogenetic patterns in TC versus compared to those in the CC control. Further, clustering analysis in both regions indicated that there was no unambiguous aggregation in TC compared to that in CC control. Of all 26 phyla detected by both regions, each region detected 2 distinct phyla exhibiting significant variations in abundance. The species unique to each treatment field accounted for less than 27% of all species and were rare taxa (abundance < 0.15%). However, a small fraction of diagnostic taxa with specific ecological functions differed significantly between TC and CC. These differences were not driven by any obvious environmental factors. The results established a comprehensive inventory of the bacterial communities associated with GM plants and indicated that transgenic cotton may not significantly affect soil microorganisms compared with conventional cotton over a three-year period. Furthermore, diagnostic taxa were provided for monitoring the perturbation in soil, but further verification in future studies is required.


Assuntos
Archaea/classificação , Bactérias/classificação , Gossypium/microbiologia , Plantas Geneticamente Modificadas/microbiologia , DNA Bacteriano/genética , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo/química , Microbiologia do Solo
13.
Phytopathology ; 108(10): 1172-1183, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29714092

RESUMO

Cotton leaf curl disease is one of the most significant constraints to the production of cotton. In the past decades our understanding of the begomoviruses (family Geminiviridae) causing the disease has improved, but little is known regarding transmission of these viruses by the different species of whiteflies in the Bemisia tabaci complex. We compared transmission efficiency of cotton leaf curl Multan virus (CLCuMuV), one of the major begomoviruses associated with cotton leaf curl disease, by four whitefly species, of which two are indigenous to Asia and two are invasive worldwide. Only the indigenous Asia II 1 species was able to transmit this virus with high efficiency. By quantifying the virus and using immunoflorescence assays, we found that the differential transmission was associated with the varying efficiency of CLCuMuV to cross the midgut of various whitefly species. Further, we verified the role of coat protein in the whitefly transmission of CLCuMuV. Based on a phylogenetic analysis of the virus coat proteins, we found that most begomoviruses associated with cotton leaf curl disease might share similar whitefly transmission characteristics. These findings advance our understanding of the nature of cotton leaf curl disease and provide information for the development of control and preventive strategies against this disease.


Assuntos
Begomovirus/fisiologia , Gossypium/microbiologia , Hemípteros/virologia , Doenças das Plantas/virologia , Animais , Begomovirus/genética , Proteínas do Capsídeo , Insetos Vetores , Filogenia , Especificidade da Espécie
14.
Plant Sci ; 272: 235-242, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29807597

RESUMO

Verticillium wilt caused by soil-borne fungus of Verticillium dahliae Kleb. is one of the most devastating diseases of cotton. Since the hierarchically organized mitogen-activated protein kinase (MAPK) cascade plays pivotal roles in signaling plant defense against pathogen attack, and the key nodes of MAPKKs (MKKs) may serve as for the convergence and divergence of signals in MAPK cascades, the possible relations between MAPK signaling and cotton Verticillium resistance were examined in this study. A total of 24 MKK genes were identified in the Gossypium hirsutum L. genome and then classified based on phylogenetic analysis. Then the regulation roles of all types of cotton MKKs in activation of cotton disease resistance were tested with the virus-induced gene silencing (VIGS) method. The results showed that three types of MKKs (GhMKK4, GhMKK6 and GhMKK9) positively regulate, while GhMKK10 negatively regulate the cotton resistance to Verticillium wilt. Further, more subtle regulation of cotton resistance mediated by MKK genes were revealed. In GhMKK9, only Gh_A12G2448 and Gh_D12G2574 displayed positive regulation of cotton resistance; whereas only Gh_A12G1883 and Gh_D12G2062 displayed negative regulation of cotton resistance in GhMKK10. All these results show that MKK members in MAPK signal cascades play dual roles in subtly regulating of cotton resistance to Verticillium wilt.


Assuntos
Resistência à Doença , Gossypium/microbiologia , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Verticillium , Genes de Plantas/genética , Gossypium/genética , Gossypium/metabolismo , Gossypium/fisiologia , Filogenia , Alinhamento de Sequência
15.
Phytopathology ; 108(7): 892-901, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29436985

RESUMO

Corynespora cassiicola is a ubiquitous fungus causing emerging plant diseases worldwide, including target spot of cotton, soybean, and tomato, which have rapidly increased in incidence and severity throughout the southeastern United States. The objectives of this study were to understand the causes for the emerging target spot epidemics in the United States by comparing phylogenetic relationships of isolates from cotton, tomato, soybean, and other crop plants and ornamental hosts, and through the determination of the host range of isolates from emerging populations. Fifty-three isolates were sampled from plants in the southeastern United States and 1,380 nucleotides from four nuclear loci were sequenced. Additionally, sequences of the same loci from 23 isolates representing each of the distinct lineages of C. cassiicola described from previous studies were included. Isolates clustered based on host of origin, regardless of the geographic location of sampling. There was no genetic diversity detected among isolates from cotton, which were genetically distinct from isolates from other host species. Furthermore, pathogenicity and virulence assays of 40 isolates from various hosts onto cotton, soybean, tomato, and cucumber showed that isolates from cotton were more aggressive to cotton than those from other hosts. Soybean and tomato were most susceptible to isolates that originated from the same host, providing evidence of host specialization. These results suggest that emerging target spot epidemics in the United States are caused by either the introduction of host-specific isolates or the evolution of more aggressive strains on each host.


Assuntos
Ascomicetos/genética , Produtos Agrícolas/microbiologia , Variação Genética , Gossypium/microbiologia , Doenças das Plantas/microbiologia , Ascomicetos/fisiologia , Doenças Transmissíveis Emergentes , Especificidade de Hospedeiro , Filogenia , Sudeste dos Estados Unidos
16.
Mol Plant Microbe Interact ; 31(6): 651-664, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29419372

RESUMO

Proteins that mediate cellular and subcellular membrane fusion are key factors in vesicular trafficking in all eukaryotic cells, including the secretion and transport of plant pathogen virulence factors. In this study, we identified vesicle-fusion components that included 22 soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), four Sec1/Munc18 (SM) family proteins, and 10 Rab GTPases encoded in the genome of the vascular wilt pathogen Verticillium dahliae Vd991. Targeted deletion of two SNARE-encoding genes in V. dahliae, VdSec22 and VdSso1, significantly reduced virulence of both mutants on cotton, relative to the wild-type Vd991 strain. Comparative analyses of the secreted protein content (exoproteome) revealed that many enzymes involved in carbohydrate hydrolysis were regulated by VdSec22 or VdSso1. Consistent with a role of these enzymes in plant cell-wall degradation, pectin, cellulose, and xylan utilization were reduced in the VdSec22 or VdSso1 mutant strains along with a loss of exoproteome cytotoxic activity on cotton leaves. Comparisons with a pathogenicity-related exoproteome revealed that several known virulence factors were not regulated by VdSec22 or VdSso1, but some of the proteins regulated by VdSec22 or VdSso1 displayed different characteristics, including the lack of a typical signal peptide, suggesting that V. dahliae employs more than one secretory route to transport proteins to extracellular sites during infection.


Assuntos
Proteínas SNARE/metabolismo , Verticillium/metabolismo , Verticillium/patogenicidade , Regulação Fúngica da Expressão Gênica/fisiologia , Gossypium/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , RNA Fúngico/genética , RNA Fúngico/metabolismo , Proteínas SNARE/genética , Transformação Genética , Verticillium/genética , Virulência
17.
Plant Physiol Biochem ; 125: 193-204, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29462745

RESUMO

Cotton, a natural fiber producing crop of huge importance for textile industry, has been reckoned as the backbone in the economy of many developing countries. Verticillium wilt caused by Verticillium dahliae reflected as the most devastating disease of cotton crop in several parts of the world. Average losses due to attack of this disease are tremendous every year. There is urgent need to develop strategies for effective control of this disease. In the last decade, progress has been made to understand the interaction between cotton-V. dahliae and several growth and pathogenicity related genes were identified. Still, most of the molecular components and mechanisms of cotton defense against Verticillium wilt are poorly understood. However, from existing knowledge, it is perceived that cotton defense mechanism primarily depends on the pre-formed defense structures including thick cuticle, synthesis of phenolic compounds and delaying or hindering the expansion of the invader through advanced measures such as reinforcement of cell wall structure, accumulation of reactive oxygen species (ROS), release of phytoalexins, the hypersensitive response and the development of broad spectrum resistance named as, systemic acquired resistance (SAR). Investigation of these defense tactics provide valuable information about the improvement of cotton breeding strategies for the development of durable, cost effective, and broad spectrum resistant varieties. Consequently, this management approach will help to reduce the use of fungicides and also minimize other environmental hazards. In the present paper, we summarized the V. dahliae virulence mechanism and comprehensively discussed the cotton molecular mechanisms of defense such as physiological, biochemical responses with the addition of signaling pathways that are implicated towards attaining resistance against Verticillium wilt.


Assuntos
Ascomicetos , Resistência à Doença , Gossypium , Doenças das Plantas/microbiologia , Transdução de Sinais , Gossypium/metabolismo , Gossypium/microbiologia , Espécies Reativas de Oxigênio/metabolismo , Sesquiterpenos/metabolismo
18.
J Appl Microbiol ; 124(6): 1589-1603, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29473989

RESUMO

AIMS: Previous research demonstrated that applying Bacillus amyloliquefaciens to cotton seeds promotes growth, alters root architecture and alleviates salt stress of cotton seedlings. This research was undertaken to further study the genetic responses elicited in cotton seedlings by this growth promoting bacterium. METHODS AND RESULTS: GeneChip microarrays and RT-qPCR were used to detect changes in gene expression in seedling roots inoculated with B. amyloliquefaciens. Roots were stained with 3'3-diaminobenzidine and phloroglucinol-HCl to determine whether treated seedlings had a greater accumulation of reactive oxygen species and lignin. Two hundred and fifty-two transcripts were differentially expressed in inoculated cotton seedling roots; 139 transcripts were up-regulated and 113 were down-regulated. Some up-regulated transcripts were related to nitrate assimilation, cell growth, hormones, transport, transcription factors and antioxidants. Five genes identified to be up-regulated using microarrays were determined to be up-regulated using RT-qPCR. Inoculated cotton seedling roots had a greater accumulation of reactive oxygen species and lignin. CONCLUSIONS: The differential expression of genes associated with diverse functions supports that B. amyloliquefaciens elicits a complex genetic response in seedling roots. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated that beneficial bacteria can alter gene expression of cotton that leads to growth promotion.


Assuntos
Bacillus amyloliquefaciens/fisiologia , Gossypium , Lignina , Raízes de Plantas , Plântula , Regulação da Expressão Gênica de Plantas/genética , Gossypium/genética , Gossypium/metabolismo , Gossypium/microbiologia , Lignina/genética , Lignina/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Espécies Reativas de Oxigênio/metabolismo , Plântula/genética , Plântula/metabolismo , Plântula/microbiologia
19.
Int J Mol Sci ; 19(1)2018 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-29342876

RESUMO

Arbuscular mycorrhizal fungi (AMF) play an important role in nutrient cycling processes and plant stress resistance. To evaluate the effect of Rhizophagus irregularis CD1 on plant growth promotion (PGP) and Verticillium wilt disease, the symbiotic efficiency of AMF (SEA) was first investigated over a range of 3% to 94% in 17 cotton varieties. The high-SEA subgroup had significant PGP effects in a greenhouse. From these results, the highest-SEA variety of Lumian 1 was selected for a two-year field assay. Consistent with the performance from the greenhouse, the AMF-mediated PGP of Lumian 1 also produced significant results, including an increased plant height, stem diameter, number of petioles, and phosphorus content. Compared with the mock treatment, AMF colonization obviously inhibited the symptom development of Verticillium dahliae and more strongly elevated the expression of pathogenesis-related genes and lignin synthesis-related genes. These results suggest that AMF colonization could lead to the mycorrhiza-induced resistance (MIR) of Lumian 1 to V. dahliae. Interestingly, our results indicated that the AMF endosymbiont could directly inhibit the growth of phytopathogenic fungi including V. dahliae by releasing undefined volatiles. In summary, our results suggest that stronger effects of AMF application result from the high-SEA.


Assuntos
Resistência à Doença , Gossypium/imunologia , Gossypium/microbiologia , Micorrizas/fisiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Simbiose , Verticillium/fisiologia , Antifúngicos/metabolismo , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Doenças das Plantas/genética
20.
Plant Cell Physiol ; 59(2): 275-289, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29165718

RESUMO

Verticillium wilt disease is one of the most destructive biotic stresses faced by cotton plants. Here, we performed a genome-wide association study (GWAS) in 215 Chinese Gossypium arboreum accessions inoculated as seedlings with Verticillium dahliae to identify candidate loci involved in wilt resistance. We identified 309 loci that had a significant association with Verticillium wilt resistance and - log(P) values >5.0; the highest signal appeared on Ca3 in a 74 kb haplotype block. Five genes were also located within this haplotype block. One of these genes, CG05, was positioned close to the most significant SNP Ca3_23037225 (14 kb); expression of the gene was induced by V. dahliae or by treatment with salicylic acid (SA). Therefore, we suggest that CG05 may respond to invasion by V. dahliae via an SA-related signaling pathway, and we designated this gene as GaGSTF9. We showed that GaGSTF9 was a positive regulator of Verticillium wilt through the use of virus-induced gene silencing (VIGS) and overexpression in Arabidopsis. In addition, the glutathione S-transferase (GST) mutant gstf9 of Arabidopsis was found to be more susceptible to Verticillium wilt than wild-type plants. The levels of endogenous SA and hydrogen peroxide had a significant effect on Arabidopsis plants that overexpressed GaGSTF9, indicating that GST may regulate reactive oxygen species content via catalytic reduction of the tripeptide glutathione (GSH), and then affect SA content. Our data demonstrated that GaGSTF9 was a key regulator mediating cotton responses to V. dahliae and a potential candidate gene for cotton genetic improvement.


Assuntos
Resistência à Doença/genética , Estudo de Associação Genômica Ampla , Glutationa Transferase/genética , Gossypium/enzimologia , Gossypium/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Verticillium/fisiologia , Arabidopsis/genética , Arabidopsis/microbiologia , Resistência à Doença/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glutationa Transferase/metabolismo , Gossypium/efeitos dos fármacos , Gossypium/genética , Peróxido de Hidrogênio/metabolismo , Mutação/genética , Fenótipo , Reguladores de Crescimento de Planta/farmacologia , Plantas Geneticamente Modificadas , Polimorfismo de Nucleotídeo Único/genética , Ácido Salicílico/metabolismo , Sementes/efeitos dos fármacos , Sementes/microbiologia , Transdução de Sinais/efeitos dos fármacos , Verticillium/efeitos dos fármacos
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