RESUMO
Endophytic bacteria, recognized as eco-friendly biofertilizers, have demonstrated the potential to enhance crop growth and yield. While the plant growth-promoting effects of endophytic bacteria have been extensively studied, the impact of weed endophytes remains less explored. In this study, we aimed to isolate endophytic bacteria from native weeds and assess their plant growth-promoting abilities in rice under varying chemical fertilization. The evaluation encompassed measurements of mineral phosphate and potash solubilization, as well as indole-3-acetic acid (IAA) production activity by the selected isolates. Two promising strains, tentatively identified as Alcaligenes faecalis (BTCP01) from Eleusine indica (Goose grass) and Metabacillus indicus (BTDR03) from Cynodon dactylon (Bermuda grass) based on 16S rRNA gene phylogeny, exhibited noteworthy phosphate and potassium solubilization activity, respectively. BTCP01 demonstrated superior phosphate solubilizing activity, while BTDR03 exhibited the highest potassium (K) solubilizing activity. Both isolates synthesized IAA in the presence of L-tryptophan, with the detection of nifH and ipdC genes in their genomes. Application of isolates BTCP01 and BTDR03 through root dipping and spraying at the flowering stage significantly enhanced the agronomic performance of rice variety CV. BRRI dhan29. Notably, combining both strains with 50% of recommended N, P, and K fertilizer doses led to a substantial increase in rice grain yields compared to control plants receiving 100% of recommended doses. Taken together, our results indicate that weed endophytic bacterial strains BTCP01 and BTDR03 hold promise as biofertilizers, potentially reducing the dependency on chemical fertilizers by up to 50%, thereby fostering sustainable rice production.
Assuntos
Alcaligenes faecalis , Endófitos , Fertilizantes , Oryza , Fosfatos , Plantas Daninhas , Oryza/microbiologia , Oryza/crescimento & desenvolvimento , Endófitos/metabolismo , Alcaligenes faecalis/metabolismo , Alcaligenes faecalis/crescimento & desenvolvimento , Plantas Daninhas/microbiologia , Plantas Daninhas/crescimento & desenvolvimento , Fosfatos/metabolismo , Ácidos Indolacéticos/metabolismo , RNA Ribossômico 16S/genética , Filogenia , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Eleusine/microbiologia , Eleusine/crescimento & desenvolvimento , Cynodon/microbiologia , Cynodon/crescimento & desenvolvimento , Potássio/metabolismoRESUMO
Supernumerary mini-chromosomes-a unique type of genomic structural variation-have been implicated in the emergence of virulence traits in plant pathogenic fungi. However, the mechanisms that facilitate the emergence and maintenance of mini-chromosomes across fungi remain poorly understood. In the blast fungus Magnaporthe oryzae (Syn. Pyricularia oryzae), mini-chromosomes have been first described in the early 1990s but, until very recently, have been overlooked in genomic studies. Here we investigated structural variation in four isolates of the blast fungus M. oryzae from different grass hosts and analyzed the sequences of mini-chromosomes in the rice, foxtail millet and goosegrass isolates. The mini-chromosomes of these isolates turned out to be highly diverse with distinct sequence composition. They are enriched in repetitive elements and have lower gene density than core-chromosomes. We identified several virulence-related genes in the mini-chromosome of the rice isolate, including the virulence-related polyketide synthase Ace1 and two variants of the effector gene AVR-Pik. Macrosynteny analyses around these loci revealed structural rearrangements, including inter-chromosomal translocations between core- and mini-chromosomes. Our findings provide evidence that mini-chromosomes emerge from structural rearrangements and segmental duplication of core-chromosomes and might contribute to adaptive evolution of the blast fungus.
Assuntos
Ascomicetos/genética , Cromossomos Fúngicos/genética , Rearranjo Gênico/genética , Genoma Fúngico/genética , Genômica/métodos , Ascomicetos/patogenicidade , Eleusine/genética , Eleusine/microbiologia , Evolução Molecular , Genes Fúngicos/genética , Variação Genética , Interações Hospedeiro-Patógeno/genética , Milhetes/genética , Milhetes/microbiologia , Oryza/genética , Oryza/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Virulência/genéticaRESUMO
Eleusine isolates (members of the Eleusine pathotype) of Pyricularia oryzae are divided into two subgroups, EC-I and EC-II, differentiated by molecular markers. A multilocus phylogenetic analysis revealed that these subgroups are very close to Eragrostis isolates. EC-II and Eragrostis isolates were exclusively virulent on finger millet and weeping lovegrass, respectively, while EC-I isolates were virulent on both. The avirulence of EC-II on weeping lovegrass was conditioned by an avirulence gene, PWL1. All EC-II isolates shared a peculiar structure (P structure) that was considered to be produced by an insertion (or translocation) of a DNA fragment carrying PWL1. On the other hand, all EC-I and Eragrostis isolates were noncarriers of PWL1 and shared a gene structure that should have predated the insertion of the PWL1-containing fragment. These results, together with phylogenetic analyses using whole-genome sequences, suggest that the Eleusine-specific subgroup (EC-II) evolved through a loss of pathogenicity on weeping lovegrass caused by a gain of PWL1.
Assuntos
Ascomicetos , Eleusine , Evolução Molecular , Genes Fúngicos , Filogenia , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/patogenicidade , Eleusine/microbiologia , Genes Fúngicos/genética , Doenças das Plantas/microbiologiaRESUMO
This study emphasizes the beneficial role of rhizo-competitive Bacillus spp. isolated from rhizospheric and non-rhizospheric soil in plant growth promotion and yield improvement via nitrogen fixation and biocontrol of Sclerotium rolfsii causing foot rot disease in Eleusine coracana (Ragi). The selection of potent rhizobacteria was based on plant-growth-promoting attributes using Venn set diagram and Bonitur scale. Bacillus pumilus MSTA8 and Bacillus amyloliquefaciens MSTD26 were selected because they were effective in root colonization, rhizosphere competence, and biofilm formation using root exudates of E. coracana L. rich with carbohydrates, proteins, and amino acids. The relative chemotaxis index of the isolates expressed the invasive behavior of the rhizosphere. During pot and field trials, the consortium of the rhizobacteria in a vermiculite carrier increased the grain yield by 37.87%, with a significant harvest index of 16.45. Soil analysis after the field trial revealed soil reclamation potentials to manage soil nutrition and fertility. Both indexes ensured crop protection and production in eco-safe ways and herald commercialization of Bacillus bio-inoculant for improvement in crop production and disease management of E. coracana.
Assuntos
Bacillus/fisiologia , Basidiomycota/fisiologia , Eleusine/microbiologia , Doenças das Plantas/prevenção & controle , Exsudatos de Plantas/análise , Microbiologia do Solo , Bacillus amyloliquefaciens/fisiologia , Bacillus pumilus/fisiologia , Quimiotaxia , Eleusine/crescimento & desenvolvimento , Fixação de Nitrogênio , Filogenia , Doenças das Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , RizosferaRESUMO
Azospirillum brasilense is a plant growth-promoting bacterium that colonizes the roots of a large number of plants, including C3 and C4 grasses. Malate has been used as a preferred source of carbon for the enrichment and isolation Azospirillum spp., but the genes involved in their transport and utilization are not yet characterized. In this study, we investigated the role of the two types of dicarboxylate transporters (DctP and DctA) of A. brasilense in their ability to colonize and promote growth of the roots of a C4 grass. We found that DctP protein was distinctly upregulated in A. brasilense grown with malate as sole carbon source. Inactivation of dctP in A. brasilense led to a drastic reduction in its ability to grow on dicarboxylates and form cell aggregates. Inactivation of dctA, however, showed a marginal reduction in growth and flocculation. The growth and nitrogen fixation of a dctP and dctA double mutant of A. brasilense were severely compromised. We have shown here that DctPQM and DctA transporters play a major and a minor role in the transport of C4-dicarboxylates in A. brasilense, respectively. Studies on inoculation of the seedlings of a C4 grass, Eleusine corcana, with A. brasilense and its dicarboxylate transport mutants revealed that dicarboxylate transporters are required by A. brasilense for an efficient colonization of plant roots and their growth.
Assuntos
Azospirillum brasilense , Transportadores de Ácidos Dicarboxílicos , Eleusine , Azospirillum brasilense/genética , Azospirillum brasilense/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Transportadores de Ácidos Dicarboxílicos/genética , Transportadores de Ácidos Dicarboxílicos/metabolismo , Eleusine/microbiologia , Regulação Bacteriana da Expressão Gênica , Inativação Gênica , Malatos/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologiaRESUMO
Copper-chitosan nanoparticle (CuChNp) was synthesized and used to study its effect on finger millet plant as a model plant system. Our objective was to explore the efficacy of CuChNp application to control blast disease of finger millet. CuChNp was applied to finger millet either as a foliar spray or as a combined application (involving seed coat and foliar spray). Both the application methods enhanced growth profile of finger millet plants and increased yield. The increased yield was nearly 89% in combined application method. Treated finger millet plants challenged with Pyricularia grisea showed suppression of blast disease development when compared to control. Nearly 75% protection was observed in the combined application of CuChNp to finger millet plants. In CuChNp treated finger millet plants, a significant increase in defense enzymes was observed, which was detected both qualitatively and quantitatively. The suppression of blast disease correlates well with increased defense enzymes in CuChNp treated finger millet plants.
Assuntos
Cobre/farmacologia , Eleusine/crescimento & desenvolvimento , Fungicidas Industriais/farmacologia , Doenças das Plantas/imunologia , Quitosana/química , Cobre/química , Resistência à Doença , Eleusine/efeitos dos fármacos , Eleusine/imunologia , Eleusine/microbiologia , Fungicidas Industriais/química , Nanopartículas/química , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Pyricularia grisea/efeitos dos fármacos , Pyricularia grisea/fisiologiaRESUMO
In the last few years, the demand for the tremendous therapeutic applications of indigenous probiotic bacteria from diversified fermented food products has surged. In view of this, the present study was documented to evaluate the anti-tubercular and probiotic properties of coagulase-negative staphylococci (CNS) indigenous to Koozh, a traditional fermented food product of South India. A total of 18 isolates were purified from Koozh, and tested for anti-tubercular activity against Mycobacterium tuberculosis H37Rv using luciferase reporter phage (LRP) assay. Among them, six isolates revealed higher percentage (>90%) of relative light unit (RLU) reduction. These six isolates were further evaluated for their in vitro probiotic attributes using standard protocols. All six staphylococci strains disclosed good probiotic properties. Moreover, Staphylococcus hominis strain MANF2 showed high cell survival percentage (92.2%) at pH 2.0 as well as towards simulated gastric juice (88.51%). Furthermore, strain MANF2 was found to be resistant to bile salt after 24 h of incubation with maximal viability of 5.71 ± 0.02 log cfu/mL, and depicted the deconjugation of bile salt as well. All the isolates exhibited strong auto-aggregation capacity (44.4 ± 1.2-68.1 ± 1.5%), and hydrophobicity against toluene (55.0 ± 1.2-72.0 ± 1.1%). Additionally, strain MANF2 was observed to be highly resistant to phenol (6.27 ± 0.01 log cfu/mL) and lysozyme (81.1 ± 1.6% viability). Most importantly, all six isolates depicted good hypocholesterolemic effect, slight ß-galactosidase activity, and moderate proteolytic property. The strains were sensitive to all the tested conventional antibiotics, except Nalidixic acid. In addition to this, all staphylococci strains demonstrated significant DPPH (2,2-Diphenyl-1-picrylhydrazyl) scavenging, hydrogen peroxide tolerance, and hydroxyl radical scavenging activity in a dose dependent manner, thereby exhibiting the potent antioxidative properties of isolates. The negative results obtained from haemolytic, DNase, and gelatinase tests revealed the non-pathogenicity and safety aspect of these strains. In a nutshell, the present investigation divulges the persuasive anti-tubercular and probiotic properties of staphylococci, particularly strain MANF2, and recommended the further exploitation of Koozh associated CNS in pharmaceutics.
Assuntos
Antibiose , Eleusine/microbiologia , Alimentos Fermentados/microbiologia , Probióticos/farmacologia , Staphylococcus/fisiologia , Coagulase/genética , Coagulase/metabolismo , Fermentação , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Índia , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/fisiologia , Probióticos/química , Staphylococcus/classificação , Staphylococcus/genética , Staphylococcus/isolamento & purificaçãoRESUMO
Finger millet is an ancient African-Indian crop that is resistant to many pathogens including the fungus, Fusarium graminearum. We previously reported the first isolation of putative fungal endophytes from finger millet and showed that the crude extracts of four strains had anti-Fusarium activity. However, active compounds were isolated from only one strain. The objectives of this study were to confirm the endophytic lifestyle of the three remaining anti-Fusarium isolates, to identify the major underlying antifungal compounds, and to initially characterize the mode(s) of action of each compound. Results of confocal microscopy and a plant disease assay were consistent with the three fungal strains behaving as endophytes. Using bio-assay guided fractionation and spectroscopic structural elucidation, three anti-Fusarium secondary metabolites were purified and characterized. These molecules were not previously reported to derive from fungi nor have antifungal activity. The purified antifungal compounds were: 5-hydroxy 2(3H)-benzofuranone, dehydrocostus lactone (guaianolide sesquiterpene lactone), and harpagoside (an iridoide glycoside). Light microscopy and vitality staining were used to visualize the in vitro interactions between each compound and Fusarium; the results suggested a mixed fungicidal/fungistatic mode of action. We conclude that finger millet possesses fungal endophytes that can synthesize anti-fungal compounds not previously reported as bio-fungicides against F. graminearum.
Assuntos
Antifúngicos , Eleusine/microbiologia , Fusarium/crescimento & desenvolvimento , Penicillium/química , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologiaRESUMO
The in vitro antifungal properties of chitosan nanoparticle and its role in protection of fingermillet plants from blast disease were evaluated. Chitosan nanoparticle inhibited the radial growth of Pyricularia grisea indicating the antifungal property. Application of chitosan nanoparticle delayed blast symptom expression on fingermillet leaves for 25days while it was on 15day in control plants. Chitosan naoparticle was able to induce the reactive oxygen species and the level of peroxidase actvitiy in leaves of fingermillet, which might be the reason for delayed symptom. The treated plants showed reduced disease incidence when compared to untreated control plants. These results suggested the role of chitosan nanoparticle in protecting fingermillet plants from P. grisea infection.
Assuntos
Quitosana/farmacologia , Eleusine/microbiologia , Fungicidas Industriais/farmacologia , Nanopartículas/química , Pyricularia grisea/efeitos dos fármacos , Eleusine/fisiologia , Fungicidas Industriais/química , Peroxidases/metabolismo , Doenças das Plantas/microbiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Pyricularia grisea/patogenicidade , Espécies Reativas de Oxigênio/metabolismoRESUMO
Finger millet is one of the small millets with high nutritive value. This crop is vulnerable to blast disease caused by Pyricularia grisea, which occurs annually during rainy and winter seasons. Leaf blast occurs at early crop stage and is highly damaging. Mapping of resistance genes and other quantitative trait loci (QTLs) for agronomic performance can be of great use for improving finger millet genotypes. Evaluation of one hundred and twenty-eight finger millet genotypes in natural field conditions revealed that leaf blast caused severe setback on agronomic performance for susceptible genotypes, most significant traits being plant height and root length. Plant height was reduced under disease severity while root length was increased. Among the genotypes, IE4795 showed superior response in terms of both disease resistance and better agronomic performance. A total of seven unambiguous QTLs were found to be associated with various agronomic traits including leaf blast resistance by association mapping analysis. The markers, UGEP101 and UGEP95, were strongly associated with blast resistance. UGEP98 was associated with tiller number and UGEP9 was associated with root length and seed yield. Cross species validation of markers revealed that 12 candidate genes were associated with 8 QTLs in the genomes of grass species such as rice, foxtail millet, maize, Brachypodium stacei, B. distachyon, Panicum hallii and switchgrass. Several candidate genes were found proximal to orthologous sequences of the identified QTLs such as 1,4-ß-glucanase for leaf blast resistance, cytokinin dehydrogenase (CKX) for tiller production, calmodulin (CaM) binding protein for seed yield and pectin methylesterase inhibitor (PMEI) for root growth and development. Most of these QTLs and their putatively associated candidate genes are reported for first time in finger millet. On validation, these novel QTLs may be utilized in future for marker assisted breeding for the development of fungal resistant and high yielding varieties of finger millet.
Assuntos
Resistência à Doença/genética , Eleusine/genética , Doenças das Plantas/microbiologia , Locos de Características Quantitativas/genética , Simulação por Computador , Produção Agrícola , Eleusine/crescimento & desenvolvimento , Eleusine/microbiologia , Estudo de Associação Genômica Ampla , Genótipo , Doenças das Plantas/genética , Folhas de Planta/microbiologia , Pyricularia grisea/patogenicidadeRESUMO
AIMS: To determine the molecular variability and develop specific Sequence Characterized Amplified Region (SCAR) marker for the detection of Magnaporthe grisea causing blast disease in finger millet. METHODS AND RESULTS: Random amplified polymorphic DNA (RAPD) was performed with 14 isolates of M. grisea using 20 random primers. SCAR marker was developed for accurate and specific detection of M. grisea infecting only finger millets. The genetic similarity coefficient within each group and variation between the groups was observed. Among the primers, OPF-08 generated a RAPD polymorphic profile that showed common fragment of 478 bp in all the isolates. This fragment was cloned and sequenced. SCAR primers, Mg-SCAR-FP and Mg-SCAR-RP, were designed using sequence of the cloned product. The specificity of the SCAR primers was evaluated using purified DNA from M. grisea isolates from finger millets and other pathogens viz., Pyricularia oryzae, Colletotrichum gloeosporioides, Colletotrichum falcatum and Colletotrichum capcisi infecting different crops. The SCAR primers amplified only specific 460 bp fragment from DNA of M. grisea isolates and this fragment was not amplified in other pathogens tested. CONCLUSION: SCAR primers distinguish blast disease of finger millet from rice as there is no amplification in the rice blast pathogen. PCR-based SCAR marker is a convenient tool for specific and rapid detection of M. grisea in finger millets. SIGNIFICANCE AND IMPACT OF THE STUDY: Genetic diversity in fungal population helps in developing a suitable SCAR marker to identify the blast pathogen at the early stage of infection.
Assuntos
Eleusine/microbiologia , Magnaporthe/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Primers do DNA/genética , Variação Genética , Magnaporthe/genética , Magnaporthe/isolamento & purificação , Reação em Cadeia da Polimerase/métodosRESUMO
The major limiting factor for production and productivity of finger millet crop is blast disease caused by Magnaporthe grisea. Since, the genome sequence information available in finger millet crop is scarce, comparative genomics plays a very important role in identification of genes/QTLs linked to the blast resistance genes using SSR markers. In the present study, a total of 58 genic SSRs were developed for use in genetic analysis of a global collection of 190 finger millet genotypes. The 58 SSRs yielded ninety five scorable alleles and the polymorphism information content varied from 0.186 to 0.677 at an average of 0.385. The gene diversity was in the range of 0.208 to 0.726 with an average of 0.487. Association mapping for blast resistance was done using 104 SSR markers which identified four QTLs for finger blast and one QTL for neck blast resistance. The genomic marker RM262 and genic marker FMBLEST32 were linked to finger blast disease at a P value of 0.007 and explained phenotypic variance (R²) of 10% and 8% respectively. The genomic marker UGEP81 was associated to finger blast at a P value of 0.009 and explained 7.5% of R². The QTLs for neck blast was associated with the genomic SSR marker UGEP18 at a P value of 0.01, which explained 11% of R². Three QTLs for blast resistance were found common by using both GLM and MLM approaches. The resistant alleles were found to be present mostly in the exotic genotypes. Among the genotypes of NW Himalayan region of India, VHC3997, VHC3996 and VHC3930 were found highly resistant, which may be effectively used as parents for developing blast resistant cultivars in the NW Himalayan region of India. The markers linked to the QTLs for blast resistance in the present study can be further used for cloning of the full length gene, fine mapping and their further use in the marker assisted breeding programmes for introgression of blast resistant alleles into locally adapted cultivars.
Assuntos
Mapeamento Cromossômico/métodos , Resistência à Doença/genética , Eleusine/genética , Eleusine/microbiologia , Genes de Plantas , Genômica/métodos , Magnaporthe/fisiologia , Doenças das Plantas/genética , Alelos , Motivos de Aminoácidos , Sequência de Aminoácidos , Cromossomos de Plantas/genética , Eleusine/imunologia , Frequência do Gene/genética , Marcadores Genéticos , Genótipo , Modelos Lineares , Repetições de Microssatélites/genética , Dados de Sequência Molecular , Oryza/genética , Fenótipo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Polimorfismo Genético , Estrutura Terciária de ProteínaRESUMO
Genetic diversity of phlD gene, an essential gene in the biosynthesis of 2,4-diacetylphloroglucinol, was studied by restriction fragment length polymorphism (RFLP) in 20 Phl-producing pseudomonads isolated from finger millet rhizosphere. RFLP analysis of phlD gene displayed three patterns with HaeIII and TaqI enzymes. phlD gene sequence closely correlated with RFLP results and revealed the existence of three new genotypes G, H and I. Further, the phylogenetic and concatenated sequence analysis of the 16S rRNA, rpoB, gyrB, rpoD genes supported the hypothesis that these genotypes G, H and I were different from reported genotypes A-F. In all phylogenetic studies, the genotype G formed a distant clade from the groups of Pseudomonas putida and P. aeruginosa (sensu strictu), but the groups H and I were closely related to P. aeruginosa/P. stutzeri group. The Phl-producing pseudomonads exhibited antagonistic activity against Pyricularia grisea (TN508), Gaeumannomyces graminis (DSM1463), Fusarium oxysporum (DSM62297), Xanthomonas campestris (DSM3586) and Erwinia persicina (HMGU155). In addition, these strains exhibited various plant growth-promoting traits. In conclusion, this study displays the existence of novel Phl-producing pseudomonads genotypes G, H and I from finger millet rhizosphere, which formed taxonomically outward phylogenetic lineage from the groups of P. putida and P. aeruginosa (sensu strictu).
Assuntos
Eleusine/microbiologia , Floroglucinol/análogos & derivados , Pseudomonas/genética , Antibiose , Ascomicetos/genética , Agentes de Controle Biológico , Eleusine/crescimento & desenvolvimento , Erwinia/fisiologia , Evolução Molecular , Fusarium/fisiologia , Genes Bacterianos , Genótipo , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Floroglucinol/metabolismo , Filogenia , Doenças das Plantas/microbiologia , Polimorfismo de Fragmento de Restrição , Pseudomonas/isolamento & purificação , Pseudomonas/metabolismo , Pyricularia grisea/fisiologia , RNA Ribossômico 16S/genética , Rizosfera , Microbiologia do Solo , Xanthomonas campestris/fisiologiaRESUMO
Finger millet (Eleusine coracana) is a subsistence crop grown in Sub-Saharan Africa and the Indian Sub-continent. Fusarium species occurring on this crop have not been reported. Approximately 13% of the Fusarium isolates recovered from finger millet growing at three different locations in eastern Uganda belong to Fusarium verticillioides, and could produce up to 18,600 µg/g of total fumonisins when cultured under laboratory conditions. These strains are all genetically unique, based on AFLP analyses, and form fertile perithecia when crossed with the standard mating type tester strains for this species. All but one of the strains is female-fertile and mating-type segregates 13:20 Mat-1:Mat-2. Three new sequences of the gene encoding translation elongation factor 1-α were found within the population. These results indicate a potential health risk for infants who consume finger millet gruel as a weaning food, and are consistent with the hypothesis that F. verticillioides originated in Africa and not in the Americas, despite its widespread association with maize grown almost anywhere worldwide.
Assuntos
Produtos Agrícolas/microbiologia , Eleusine/microbiologia , Fusarium/isolamento & purificação , Ração Animal/análise , Ração Animal/microbiologia , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Eleusine/crescimento & desenvolvimento , Contaminação de Alimentos , Microbiologia de Alimentos , Fumonisinas/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/classificação , Fusarium/crescimento & desenvolvimento , Fusarium/metabolismo , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Tipagem Molecular , Técnicas de Tipagem Micológica , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Fator 1 de Elongação de Peptídeos/genética , Fator 1 de Elongação de Peptídeos/metabolismo , Filogenia , Especificidade da Espécie , UgandaRESUMO
Finger millet plants conferring resistance to leaf blast disease have been developed by inserting a rice chitinase (chi11) gene through Agrobacterium-mediated transformation. Plasmid pHyg-Chi.11 harbouring the rice chitinase gene under the control of maize ubiquitin promoter was introduced into finger millet using Agrobacterium strain LBA4404 (pSB1). Transformed plants were selected and regenerated on hygromycin-supplemented medium. Transient expression of transgene was confirmed by GUS histochemical staining. The incorporation of rice chitinase gene in R0 and R1 progenies was confirmed by PCR and Southern blot analyses. Expression of chitinase gene in finger millet was confirmed by Western blot analysis with a barley chitinase antibody. A leaf blast assay was also performed by challenging the transgenic plants with spores of Pyricularia grisea. The frequency of transient expression was 16.3% to 19.3%. Stable frequency was 3.5% to 3.9%. Southern blot analysis confirmed the integration of 3.1 kb chitinase gene. Western blot analysis detected the presence of 35 kDa chitinase enzyme. Chitinase activity ranged from 19.4 to 24.8. In segregation analysis, the transgenic R1 lines produced three resistant and one sensitive for hygromycin, confirming the normal Mendelian pattern of transgene segregation. Transgenic plants showed high level of resistance to leaf blast disease compared to control plants. This is the first study reporting the introduction of rice chitinase gene into finger millet for leaf blast resistance.
Assuntos
Resistência à Doença/genética , Eleusine/genética , Magnaporthe , Plantas Geneticamente Modificadas/genética , Transformação Genética/genética , Agrobacterium , Análise de Variância , Southern Blotting , Western Blotting , Quitinases/genética , Quitinases/metabolismo , Primers do DNA/genética , Eleusine/microbiologia , Histocitoquímica , Oryza/genética , Plantas Geneticamente Modificadas/microbiologia , Plasmídeos/genética , Reação em Cadeia da PolimeraseRESUMO
In this study, host-specific forms of the blast pathogen Magnaporthe oryzae in sub-Saharan Africa (SSA) were characterised from distinct cropping locations using a combination of molecular and biological assays. Finger millet blast populations in East Africa revealed a continuous genetic variation pattern and lack of clonal lineages, with a wide range of haplotypes. M. oryzae populations lacked the grasshopper (grh) element (96%) and appeared distinct to those in Asia. An overall near equal distribution (47-53%) of the mating types MAT1-1 and MAT1-2, high fertility status (84-89%) and the dominance of hermaphrodites (64%) suggest a strong sexual reproductive potential. Differences in pathogen aggressiveness and lack of cultivar incompatibility suggest the importance of quantitative resistance. Rice blast populations in West Africa showed a typical lineage-based structure. Among the nine lineages identified, three comprised ~90% of the isolates. Skewed distribution of the mating types MAT1-1 (29%) and MAT1-2 (71%) was accompanied by low fertility. Clear differences in cultivar compatibility within and between lineages suggest R gene-mediated interactions. Distinctive patterns of genetic diversity, sexual reproductive potential and pathogenicity suggest adaptive divergence of host-specific forms of M. oryzae populations linked to crop domestication and agricultural intensification.
Assuntos
Eleusine/microbiologia , Variação Genética , Magnaporthe/genética , Magnaporthe/patogenicidade , Oryza/microbiologia , Doenças das Plantas/microbiologia , África Subsaariana , África Oriental , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Haplótipos/genética , Interações Hospedeiro-Patógeno/genéticaRESUMO
Fructansucrase and fructan produced from Lactobacillus fermentum AKJ15 were isolated from seeds of Kodo ko jaanr, a fermented mild-alcoholic beverage prepared in North East India. The strain was identified by 16S rRNA gene sequence analysis and biochemical characterization. The strain displayed maximum fructansucrase activity of 4.3 U/ml (1.02 U/mg) at 28°C at 180 rpm. The enzyme purified by polyethylene glycol-400 gave specific activity of 5 U/mg and showed 90 kDa band on non-denaturing Sodium Dodecyl Sulphate-Poly Acrylamide Gel Electrophoresis (SDS-PAGE). The purified enzyme confirmed the presence of fructan by periodic acid Schiff's staining which showed magenta colour bands with both sucrose and raffinose. The strain produced 10.2 mg/ml fructan in broth under optimized culture conditions. The purified fructansucrase displayed V(max) of 5.42 U/mg and K(m) of 16.65 mM. The enzyme showed maximum activity at 30°C and at pH 5. The structure of fructan was analysed by (1)H and (13)C NMR spectra confirming ß-(2-1) and ß-(2-6) linkages.
Assuntos
Bebidas/microbiologia , Eleusine/química , Frutanos/biossíntese , Limosilactobacillus fermentum/metabolismo , Preparações de Plantas/metabolismo , Sacarase/metabolismo , Sequência de Bases , Eletroforese em Gel de Poliacrilamida , Eleusine/microbiologia , Fermentação , Frutanos/química , Frutanos/isolamento & purificação , Índia , Limosilactobacillus fermentum/genética , Estrutura Molecular , Peso Molecular , RNA Ribossômico 16S/genética , Rafinose/análise , Sementes/química , Sementes/microbiologia , Especificidade da Espécie , Sacarase/química , Sacarase/isolamento & purificação , Sacarose/análiseRESUMO
Magnaporthe grisea, the blast fungus is one of the main pathological threats to finger millet crop worldwide. A systematic search for the blast resistance gene analogs was carried out, using functional molecular markers. Three-fourths of the recognition-dependent disease resistance genes (R-genes) identified in plants encodes nucleotide binding site (NBS) leucine-rich repeat (LRR) proteins. NBS-LRR homologs have only been isolated on a limited scale from Eleusine coracana. Genomic DNA sequences sharing homology with NBS region of resistance gene analogs were isolated and characterized from resistant genotypes of finger millet using PCR based approach with primers designed from conserved regions of NBS domain. Attempts were made to identify molecular markers linked to the resistance gene and to differentiate the resistant bulk from the susceptible bulk. A total of 9 NBS-LRR and 11 EST-SSR markers generated 75.6 and 73.5% polymorphism respectively amongst 73 finger millet genotypes. NBS-5, NBS-9, NBS-3 and EST-SSR-04 markers showed a clear polymorphism which differentiated resistant genotypes from susceptible genotypes. By comparing the banding pattern of different resistant and susceptible genotypes, five DNA amplifications of NBS and EST-SSR primers (NBS-05(504,) NBS-09(711), NBS-07(688), NBS-03(509) and EST-SSR-04(241)) were identified as markers for the blast resistance in resistant genotypes. Principal coordinate plot and UPGMA analysis formed similar groups of the genotypes and placed most of the resistant genotypes together showing a high level of genetic relatedness and the susceptible genotypes were placed in different groups on the basis of differential disease score. Our results provided a clue for the cloning of finger millet blast resistance gene analogs which not only facilitate the process of plant breeding but also molecular characterization of blast resistance gene analogs from Eleusine coracana.
Assuntos
Eleusine/genética , Eleusine/microbiologia , Marcadores Genéticos , Imunidade Inata/genética , Doenças das Plantas/microbiologia , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Genótipo , Magnaporthe/patogenicidade , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Eleusine isolates (members of the Eleusine subgroup) of Pyricularia oryzae are divided into two groups, Ec-I and Ec-II, differentiated by molecular markers. A multilocus phylogenetic analysis and DNA fingerprinting suggested that Ec-I isolates are very close to Eragrostis isolates rather than Ec-II isolates. Infection assays revealed that Ec-II and Eragrostis isolates were exclusively virulent on finger millet and weeping lovegrass, respectively, whereas Ec-I isolates were virulent on both. The avirulence or virulence on weeping lovegrass perfectly corresponded to the presence or absence of an avirulence gene, PWL1; all Ec-II isolates carried an identical, functional PWL1, whereas none of Ec-I isolates or Eragrostis isolates carried it. A comparison of PWL1 flanking regions revealed that Ec-II isolates had a peculiar structure produced by an insertion (or translocation) of a DNA fragment carrying PWL1. Based on these results, a model was constructed which illustrated possible pathways to the establishment of the Eleusine subgroup.
Assuntos
Ascomicetos/classificação , Ascomicetos/genética , Evolução Biológica , Eleusine/microbiologia , Proteínas Fúngicas/genética , Clonagem Molecular , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Especificidade da EspécieRESUMO
The present investigation has been carried out to highlight the importance of germination and fermentation of finger millet with Monascus purpureus. Finger millet was subjected to (i) germination, (ii) to fermentation with M. purpureus, and (iii) germination followed by fermentation with M. purpureus. The results of this experiment suggest that the germinated (72 h) finger millet fermented (10 days) with M. purpureus showed reduction in phytic acid and tannin contents by 88.8% and 90.1%, respectively, with an increase of 61.5% HCl-extractable minerals, reducing sugars and soluble proteins thereby supporting the production of antihypercholesterolemic metabolite, statin.