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1.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445145

RESUMO

The main goal of growing plants under various photoperiods is to optimize photosynthesis for using the effect of day length that often acts on plants in combination with biotic and/or abiotic stresses. In this study, Brassica juncea plants were grown under four different day-length regimes, namely., 8 h day/16 h night, 12 h day/12 h night, 16 h day/8 h night, and continuous light, and were infected with a necrotrophic fungus Alternaria brassicicola. The development of necroses on B. juncea leaves was strongly influenced by leaf position and day length. The largest necroses were formed on plants grown under a 16 h day/8 h night photoperiod at 72 h post-inoculation (hpi). The implemented day-length regimes had a great impact on leaf morphology in response to A. brassicicola infection. They also influenced the chlorophyll and carotenoid contents and photosynthesis efficiency. Both the 1st (the oldest) and 3rd infected leaves showed significantly higher minimal fluorescence (F0) compared to the control leaves. Significantly lower values of other investigated chlorophyll a fluorescence parameters, e.g., maximum quantum yield of photosystem II (Fv/Fm) and non-photochemical quenching (NPQ), were observed in both infected leaves compared to the control, especially at 72 hpi. The oldest infected leaf, of approximately 30% of the B. juncea plants, grown under long-day and continuous light conditions showed a 'green island' phenotype in the form of a green ring surrounding an area of necrosis at 48 hpi. This phenomenon was also reflected in changes in the chloroplast's ultrastructure and accelerated senescence (yellowing) in the form of expanding chlorosis. Further research should investigate the mechanism and physiological aspects of 'green islands' formation in this pathosystem.


Assuntos
Alternaria/patogenicidade , Mostardeira/microbiologia , Mostardeira/fisiologia , Necrose/microbiologia , Necrose/patologia , Fotossíntese/fisiologia , Doenças das Plantas/microbiologia , Carotenoides/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Fluorescência , Mostardeira/metabolismo , Necrose/metabolismo , Fotoperíodo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
2.
Biomolecules ; 11(6)2021 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204730

RESUMO

Pervasive use of chlorpyrifos (CP), an organophosphorus pesticide, has been proven to be fatal for plant growth, especially at higher concentrations. CP poisoning leads to growth inhibition, chlorosis, browning of roots and lipid and protein degradation, along with membrane dysfunction and nuclear damage. Plants form a linking bridge between the underground and above-ground communities to escape from the unfavourable conditions. Association with beneficial rhizobacteria promotes the growth and development of the plants. Plant hormones are crucial regulators of basically every aspect of plant development. The growing significance of plant hormones in mediating plant-microbe interactions in stress recovery in plants has been extensively highlighted. Hence, the goal of the current study was to investigate the effect of 24-epibrassinolide (EBL) and PGPRs (Pseudomonas aeruginosa (Ma), Burkholderia gladioli (Mb)) on growth and the antioxidative defence system of CP-stressed Brassica juncea L. seedlings. CP toxicity reduced the germination potential, hypocotyl and radicle development and vigour index, which was maximally recuperated after priming with EBL and Mb. CP-exposed seedlings showed higher levels of superoxide anion (O2-), hydrogen peroxide (H2O2), lipid peroxidation and electrolyte leakage (EL) and a lower level of nitric oxide (NO). In-vivo visualisation of CP-stressed seedlings using a light and fluorescent microscope also revealed the increase in O2-, H2O2 and lipid peroxidation, and decreased NO levels. The combination of EBL and PGPRs reduced the reactive oxygen species (ROS) and malondialdehyde (MDA) contents and improved the NO level. In CP-stressed seedlings, increased gene expression of defence enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APOX), glutathione peroxidase (GPOX), dehydroascorbate reductase (DHAR) and glutathione reductase (GPOX) was seen, with the exception of catalase (CAT) on supplementation with EBL and PGPRs. The activity of nitrate reductase (NR) was likewise shown to increase after treatment with EBL and PGPRs. The results obtained from the present study substantiate sufficient evidence regarding the positive association of EBL and PGPRs in amelioration of CP-induced oxidative stress in Brassica juncea seedlings by strengthening the antioxidative defence machinery.


Assuntos
Brassinosteroides/metabolismo , Burkholderia gladioli/crescimento & desenvolvimento , Clorpirifos/farmacocinética , Mostardeira , Pseudomonas aeruginosa/crescimento & desenvolvimento , Plântula , Esteroides Heterocíclicos/metabolismo , Mostardeira/crescimento & desenvolvimento , Mostardeira/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia
3.
Plant Mol Biol ; 106(6): 505-520, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34176052

RESUMO

KEY MESSAGE: Gene expression analysis coupled with in-planta studies showed that specific Gßγ combination regulates plant growth and defence traits in the allotetraploid Brassica juncea. Plant heterotrimeric G-proteins regulate a wide range of responses despite their limited repertoire of core components. The roles and functional interactions between different G-protein subunits are quite perplexing, which get further complicated with polyploidy. Here, we show that the allotetraploid Brassica juncea comprises multiple homologs of G-protein genes, encoding six BjuGß and ten highly divergent BjuGγ subunit proteins, later being classified into type-A1, type-A2 and type-C Gγ proteins. The encoded BjuGß and BjuGγ proteins shared close evolutionary relationship and have retained distinct spatio-temporal expression patterns during plant developmental stages and in response to the necrotrophic pathogen, Sclerotinia sclerotiorum. RNAi based suppression of BjuGß and BjuGγ genes suggested functional overlap and selectivity of BjuGßs with three distinct BjuGγ type subunits, to regulate plant height (BjuGßγA2 and BjuGßγC), seed weight (BjuGßGγA1 and BjuGßGγC), silique size (BjuGßGγC) and pathogen response (BjuGßGγA1 and BjuGßGγC). Further, the triplicated BjuGß genes, formed due to Brassica specific whole-genome-triplication event, showed differential involvement during pathogen response, wherein overexpression of BjuGß2 displayed higher resistance to Sclerotinia infection. Taken together, our study demonstrates that multiple BjuGß and BjuGγ proteins have retained distinct spatio-temporal expression and functional selectivity to regulate specific plant growth and defence traits in the oilseed B. juncea.


Assuntos
Subunidades beta da Proteína de Ligação ao GTP/genética , Subunidades gama da Proteína de Ligação ao GTP/genética , Mostardeira/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Poliploidia , Ascomicetos/fisiologia , Resistência à Doença/genética , Subunidades beta da Proteína de Ligação ao GTP/classificação , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/classificação , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Modelos Genéticos , Mostardeira/crescimento & desenvolvimento , Mostardeira/microbiologia , Filogenia , Doenças das Plantas/microbiologia , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Ligação Proteica , Interferência de RNA
4.
Int J Food Microbiol ; 347: 109199, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-33878643

RESUMO

Zhacai is a traditional fermented vegetable that has been consumed in China for centuries. It is currently manufactured by spontaneous fermentation and therefore mostly relies on the activities of autochthonous microorganisms. Here, we characterized microbial community dynamics and associated biochemical changes in 12% salted Zhacai during a 90-day spontaneous fermentation process using high-throughput sequencing and chromatography-based approaches to identify associations between microorganisms and fermentation characteristics. Amplicon sequencing targeting bacterial 16S rRNA genes revealed that bacterial communities were dominated by halophilic bacteria (HAB, i.e., Halomonas and Idiomarina) and lactic acid bacteria (LAB, i.e., Lactobacillus-related genera and Weissella) after 30 days of fermentation. In addition, the relative abundances of the fungal genera Debaryomyces, Sterigmatomyces, and Sporidiobolus increased as fermentation progressed. Concomitantly, pH decreased while titratable acidity increased during fermentation, along with associated variation in biochemical profiles. Overall, the levels of organic acids (i.e., lactic and acetic acid), free amino acids (i.e., alanine, lysine, and glutamic acid), and volatiles (i.e., alcohols, esters, aldehydes, and ketones) increased in mature Zhacai. In addition, the abundances of Lactobacillus-related species, Halomonas spp., Idiomarina loihiensis, as well as that of the yeast Debaryomyces hansenii, were strongly correlated with increased concentrations of organic acids, amino acids, biogenic amines, and volatiles. This study provides new detailed insights into the succession of microbial communities and their potential roles in Zhacai fermentation.


Assuntos
Alteromonadaceae/isolamento & purificação , Fungos/isolamento & purificação , Lactobacillales/isolamento & purificação , Mostardeira/microbiologia , Weissella/isolamento & purificação , Alteromonadaceae/genética , Alteromonadaceae/metabolismo , Aminoácidos/metabolismo , Aminas Biogênicas/metabolismo , Reatores Biológicos , China , Fermentação , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillales/genética , Lactobacillales/metabolismo , Microbiota , RNA Ribossômico 16S/genética , Weissella/genética , Weissella/metabolismo
5.
Molecules ; 26(6)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809305

RESUMO

Plant growth-promoting rhizobacteria (PGPR) mediate heavy metal tolerance and improve phytoextraction potential in plants. The present research was conducted to find the potential of bacterial strains in improving the growth and phytoextraction abilities of Brassica nigra (L.) K. Koch. in chromium contaminated soil. In this study, a total of 15 bacterial strains were isolated from heavy metal polluted soil and were screened for their heavy metal tolerance and plant growth promotion potential. The most efficient strain was identified by 16S rRNA gene sequencing and was identified as Bacillus cereus. The isolate also showed the potential to solubilize phosphate and synthesize siderophore, phytohormones (indole acetic acid, cytokinin, and abscisic acid), and osmolyte (proline and sugar) in chromium (Cr+3) supplemented medium. The results of the present study showed that chromium stress has negative effects on seed germination and plant growth in B. nigra while inoculation of B. cereus improved plant growth and reduced chromium toxicity. The increase in seed germination percentage, shoot length, and root length was 28.07%, 35.86%, 19.11% while the fresh and dry biomass of the plant increased by 48.00% and 62.16%, respectively, as compared to the uninoculated/control plants. The photosynthetic pigments were also improved by bacterial inoculation as compared to untreated stress-exposed plants, i.e., increase in chlorophyll a, chlorophyll b, chlorophyll a + b, and carotenoid was d 25.94%, 10.65%, 20.35%, and 44.30%, respectively. Bacterial inoculation also resulted in osmotic adjustment (proline 8.76% and sugar 28.71%) and maintained the membrane stability (51.39%) which was also indicated by reduced malondialdehyde content (59.53% decrease). The antioxidant enzyme activities were also improved to 35.90% (superoxide dismutase), 59.61% (peroxide), and 33.33% (catalase) in inoculated stress-exposed plants as compared to the control plants. B. cereus inoculation also improved the uptake, bioaccumulation, and translocation of Cr in the plant. Data showed that B. cereus also increased Cr content in the root (2.71-fold) and shoot (4.01-fold), its bioaccumulation (2.71-fold in root and 4.03-fold in the shoot) and translocation (40%) was also high in B. nigra. The data revealed that B. cereus is a multifarious PGPR that efficiently tolerates heavy metal ions (Cr+3) and it can be used to enhance the growth and phytoextraction potential of B. nigra in heavy metal contaminated soil.


Assuntos
Bacillus cereus/fisiologia , Cromo/farmacocinética , Mostardeira/metabolismo , Mostardeira/microbiologia , Poluentes do Solo/farmacocinética , Antioxidantes/metabolismo , Bacillus cereus/genética , Biodegradação Ambiental , Clorofila/metabolismo , Genes Bacterianos , Mostardeira/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , Rhizobiaceae/fisiologia , Microbiologia do Solo , Estresse Fisiológico , Simbiose
6.
Theor Appl Genet ; 134(7): 2035-2050, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33768283

RESUMO

KEY MESSAGE: One hundred and sixty-seven B. juncea varieties were genotyped on the 90K Brassica assay (42,914 SNPs), which led to the identification of sixteen candidate genes for Rlm6. Brassica species are at high risk of severe crop loss due to pathogens, especially Leptosphaeria maculans (the causal agent of blackleg). Brassica juncea (L.) Czern is an important germplasm resource for canola improvement, due to its good agronomic traits, such as heat and drought tolerance and high blackleg resistance. The present study is the first using genome-wide association studies to identify candidate genes for blackleg resistance in B. juncea based on genome-wide SNPs obtained from the Illumina Infinium 90 K Brassica SNP array. The verification of Rlm6 in B. juncea was performed through a cotyledon infection test. Genotyping 42,914 single nucleotide polymorphisms (SNPs) in a panel of 167 B. juncea lines revealed a total of seven SNPs significantly associated with Rlm6 on chromosomes A07 and B04 in B. juncea. Furthermore, 16 candidate Rlm6 genes were found in these regions, defined as nucleotide binding site leucine-rich-repeat (NLR), leucine-rich repeat RLK (LRR-RLK) and LRR-RLP genes. This study will give insights into the blackleg resistance in B. juncea and facilitate identification of functional blackleg resistance genes which can be used in Brassica breeding.


Assuntos
Resistência à Doença/genética , Leptosphaeria/patogenicidade , Mostardeira/genética , Doenças das Plantas/genética , Genes de Plantas , Estudos de Associação Genética , Genótipo , Mostardeira/microbiologia , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único
7.
J Sci Food Agric ; 101(4): 1646-1658, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888329

RESUMO

BACKGROUND: Industrial Fuling Zhacai is pickled by a method summarized as 'three times pickled and pressed', in which raw mustard tubers are subjected to three stages of pickling in different salt concentrations, with a pressing operation at the end of each stage to remove brine. This study used Illumina MiSeq technology and multivariate statistical analyses to investigate microbial community succession during the pickling process and its correlation with Zhacai biochemical indices. RESULTS: A total of 19 phyla, 208 genera, and 295 species of bacteria were identified. Lactobacillus was the dominant genus of bacteria in all three stages and Lactobacillus sakei was the dominant species in the first and second stages. A total of six phyla, 200 genera and 301 species of fungi were also identified. According to a PICRUSt2 prediction, the main functions of the bacterial and fungal communities were carbohydrate and protein metabolism, while alcohol metabolism was also a function of fungi. Nine bacterial genera closely correlated with Zhacai biochemical indices: Acinetobacter, Pseudomonas, Pedobacter, Erwinia, Lactobacillus, Chryseobacterium, Flavobacterium, Duganella, and Paenarthrobacter. Six genera of fungi correlated closely: Penicillium, Cystobasidium, Cladosporium, Plenodomus, Aspergillus, and Simplicillium. All these genera probably originated from the surface microorganisms of raw mustard tuber. CONCLUSION: This study reveals the succession patterns of microbial community structures during the pickling process of industrial Zhacai and infers the core functional flora, providing reference data for Zhacai pickling process control. © 2020 Society of Chemical Industry.


Assuntos
Bactérias/isolamento & purificação , Alimentos e Bebidas Fermentados/microbiologia , Fungos/isolamento & purificação , Microbiota , Mostardeira/microbiologia , Bactérias/classificação , Bactérias/genética , Fermentação , Fungos/classificação , Fungos/genética , Metagenômica
8.
Plant Physiol Biochem ; 155: 626-636, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32858425

RESUMO

Brassica genus comprises many prominent species valuable for human nutrition including vegetable crops and oilseed. Production of B. juncea is challenged by many abiotic and biotic stresses, Alternaria blight caused by a necrotrophic fungal pathogen Alternaria brassicae is one of the most prominent diseases of cruciferous crops including B. juncea. However, some closely related wild species like Sinapis alba and Camelina sativa exhibit a variable level of resistance towards the pathogen. Apart from the host resistance, intra-specific pathogen variability also influences disease severity to a larger extent. In this study, we identified and isolated two strains of A. brassicae viz ABS1 and ABS2 exhibiting morphological and pathological variability. These isolates were further used to artificially inoculate B. juncea and two of its wild relatives under in-vitro as well as in-vivo conditions to inspect their pathogenicity in a susceptible, a moderately resistant and a highly resistant host. virulent isolate (ABS2) was able to readily establish infection in all the three species whereas the less virulent isolate (ABS1) readily infected susceptible species B. juncea but delayed and mild infection was noticed in tolerant hosts. Variable physiological and molecular host response towards the differential level of virulence of pathogen were established with many confirmatory experiments like DAB staining study, Disease severity index and microscopic analysis. Real-time PCR results confirm that these two isolates induce a variable level of induction in genes PR1 and PDF1.2 within 48 h of the artificial inoculation in B. juncea and its wild relatives.


Assuntos
Alternaria/patogenicidade , Brassicaceae/microbiologia , Doenças das Plantas/microbiologia , Virulência , Brassicaceae/fisiologia , Resistência à Doença , Mostardeira/microbiologia , Mostardeira/fisiologia , Sinapis/microbiologia , Sinapis/fisiologia
9.
Environ Microbiol ; 22(11): 4545-4556, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32656968

RESUMO

Agricultural production is dependent on inputs of nitrogen (N) whose cycle relies on soil and crop microbiomes. Crop diversification has increased productivity; however, its impact on the expression of microbial genes involved in N-cycling pathways remains unknown. Here, we assessed N-cycling gene expression patterns in the root and rhizosphere microbiomes of five oilseed crops as influenced by three 2-year crop rotations. The first phase consisted of fallow, lentil or wheat, and the second phase consisted of one of five oilseed crops. Expression of bacterial amoA, nirK and nirS genes showed that the microbiome of Ethiopian mustard had the lowest and that of camelina the highest potential for N loss. A preceding rotation phase of lentil significantly increased the expression of nifH gene by 23% compared with wheat and improved nxrA gene expression by 51% with chemical fallow in the following oilseed crops respectively. Lentil substantially increased biological N2 fixation and reduced denitrification in the following oilseed crops. Our results also revealed that most N-cycling gene transcripts are more abundant in the microbiomes associated with roots than with the rhizosphere. The outcome of our investigation brings a new level of understanding on how crop diversification and rotation sequences are related to N-cycling in annual cropping systems.


Assuntos
Camellia/metabolismo , Produtos Agrícolas/microbiologia , Lens (Planta)/metabolismo , Mostardeira/metabolismo , Ciclo do Nitrogênio/fisiologia , Triticum/metabolismo , Agricultura/métodos , Bactérias/genética , Camellia/microbiologia , Produção Agrícola/métodos , Lens (Planta)/microbiologia , Microbiota/fisiologia , Mostardeira/microbiologia , Nitrogênio/metabolismo , Ciclo do Nitrogênio/genética , Raízes de Plantas/microbiologia , Rizosfera , Solo , Microbiologia do Solo , Triticum/microbiologia
10.
J Hazard Mater ; 390: 121806, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32058900

RESUMO

An emerging stress of nanomaterials in soil and water is of great concern as it limits crop productivity and affects humans as well. Therefore, it is required to manage this problem. Silicon and plant growth promoting rhizobacteria has gained the engaging role in agriculture as (bio-)fertilizers. However, their role against silver nanoparticles (AgNPs) is still not known. Hence, present study was envisaged to investigate role of Si, PGPR and phytohormone indole acetic acid (IAA) in regulating AgNP stress in Brassica juncea seedlings. The study highlighted the impact of various treatments with respect to overproduction of reactive oxygen species, signaling molecule nitric oxide, oxidative markers like antioxidant enzymes and nonenzymatic components of ascorbate-glutathione pathway. Interestingly, silicon when present with AgNPs enhanced toxicity by reducing growth and mechanistic properties of B. juncea. Moreover, the results highlight the role of PGPR and IAA towards reduction in toxicity by promoting the plant growth under stressed conditions. Treatments AgNP + Si + PGPR/IAA were observed to significantly reduce the stress and enhance plant growth against treatment AgNPs alone. This reversal in toxicity by PGPR and IAA along with Si suggests the idea to formulate and utilize their combination as biofertilizers for eradicating the stress in near future.


Assuntos
Bacillus thuringiensis , Nanopartículas Metálicas/toxicidade , Mostardeira/efeitos dos fármacos , Óxido Nítrico/metabolismo , Rizoma/microbiologia , Silício/toxicidade , Prata/toxicidade , Ácido Ascórbico/metabolismo , Glutationa/metabolismo , Ácidos Indolacéticos/farmacologia , Mostardeira/crescimento & desenvolvimento , Mostardeira/microbiologia
11.
BMC Plant Biol ; 20(1): 63, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32028891

RESUMO

BACKGROUND: Microbes isolated from hyperaccumulating plants have been reported to be effective in achieving higher phytoextraction efficiency. The plant growth-promoting bacteria (PGPB) SaMR12 from the cadmium (Cd)/zinc hyperaccumulator Sedum alfredii Hance could promote the growth of a non-host plant, oilseed rape, under Cd stress. However, the effect of SaMR12 on Brasscia juncea antioxidative response under Cd exposure was still unclear. RESULTS: A hydroponic experiment was conducted to study the effects of Sphingomonas SaMR12 on its non-host plant Brassica juncea (L.) Czern. under four different Cd treatments. The results showed that SaMR12 could colonize and aggregate in the roots and then move to the shoots. SaMR12 inoculation promoted plant growth by up to 71% in aboveground biomass and 81% in root biomass over that of the non-inoculated plants. SaMR12-inoculated plants significantly enhanced root Cd accumulation in the 10 and 20 µM Cd treatments, with 1.72- and 0.86-fold increases, respectively, over that of the non-inoculated plants. SaMR12 inoculation not only decreased shoot hydrogen peroxide (H2O2) content by up to 38% and malondialdehyde (MDA) content by up to 60% but also reduced proline content by 7-30% in shoots and 17-32% in roots compared to the levels in non-inoculated plants. Additionally, SaMR12 inoculation promoted the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and facilitated the relative gene expression levels of dehydroascorbate reductase (DHAR) and glutathione reductase (GR) involved in the glutathione (GSH)-ascorbic acid (AsA) cycle. CONCLUSIONS: The results demonstrated that, under Cd stress, SaMR12 inoculation could activate the antioxidative response of B. juncea by decreasing the concentrations of H2O2, MDA and proline, increasing the activities of antioxidative enzymes, and regulating the GSH-AsA cycle. These results provide a theoretical foundation for the potential application of hyperaccumulator endophytic bacteria as remediating agents to improve heavy metal tolerance within non-host plant species, which could further improve phytoextraction efficiency.


Assuntos
Cádmio/efeitos adversos , Endófitos/fisiologia , Mostardeira/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Sphingomonas/fisiologia , Antioxidantes , Ácido Ascórbico , Expressão Gênica , Glutationa , Mostardeira/genética , Mostardeira/crescimento & desenvolvimento , Mostardeira/microbiologia
12.
Plant Cell Environ ; 43(8): 1815-1826, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32096568

RESUMO

Plants can enhance their defence against herbivorous insects by responding to insect egg depositions preceding larval feeding. The similarity of plant responses to insect eggs with those to phytopathogens gave rise to the hypothesis that egg-associated microbes might act as elicitors. We tested this hypothesis by investigating first if elimination of microbes in the butterfly Pieris brassicae changes the responses of Brassica nigra and Arabidopsis thaliana to eggs and larvae of this insect species. An antibiotic treatment of butterflies mitigated the plant transcriptional response to the eggs and the egg-mediated enhancement of the plant's defence against larvae. However, application of cultivated microbial isolates from the eggs onto Arabidopsis thaliana did not enhance the plant's anti-herbivore defence. Instead, application of an egg-associated glandular secretion, which is attaching the eggs to the leaves, elicited the enhancing effect on the plant's defence against larvae. However, this effect was only achieved when the secretion was applied in similar quantities as released by control butterflies, but not when applied in the reduced quantity as released by antibiotic-treated butterflies. We conclude that glandular secretions rather than egg-associated microbes act in a dose-dependent manner as elicitor of the egg-mediated enhancement of the plant's defence against insect larvae.


Assuntos
Arabidopsis/fisiologia , Borboletas/fisiologia , Mostardeira/fisiologia , Óvulo/microbiologia , Animais , Antibacterianos/farmacologia , Arabidopsis/microbiologia , Glândulas Exócrinas/metabolismo , Feminino , Regulação da Expressão Gênica de Plantas , Larva , Mostardeira/microbiologia , Óvulo/efeitos dos fármacos , Óvulo/fisiologia , Folhas de Planta
13.
Fungal Biol ; 124(1): 44-53, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31892376

RESUMO

Alternaria blight is one of the most devastating diseases of rapeseed-mustard caused by a necrotrophic fungus Alternaria brassicae. Lack of satisfactory resistance resource in Brassica is still a main obstruction for developing resistance against Alternaria. In this study, we have selected Brassica juncea, Sinapis alba and Camelina sativa to understand and unravel the mechanism of disease resistance against Alternaria. Histopathological studies showed early onset of necrosis in B. juncea (1 dpi) and delayed in S. alba (2 dpi) and C. sativa (3 dpi) respectively. Early and enhanced production of hydrogen peroxide (H2O2) was observed in C. sativa and S. alba (6 hpi) when compared to B. juncea (12 hpi). An increase in catalase activity was observed in both C. sativa (36 % at 6 hpi) and S. alba (15 % at 12 hpi), whereas it significantly decreased in B. juncea at 6 hpi (23 %), 12 hpi (30 %) and 24 hpi (8 %). Gene expression analysis showed induction of PR-3 and PR-12 genes only in C. sativa and S. alba when compared to B. juncea suggesting their vital role for Alternaria resistance. In contrast, SA marker genes were significantly expressed in B. juncea only which provides evidence of hormonal cross talk in B. juncea during Alternaria infection thereby increasing its susceptibility.


Assuntos
Alternaria/patogenicidade , Brassicaceae/microbiologia , Mostardeira/microbiologia , Doenças das Plantas/microbiologia , Sinapis/microbiologia , Brassicaceae/genética , Brassicaceae/metabolismo , Catalase/metabolismo , Resistência à Doença , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Peróxido de Hidrogênio/metabolismo , Mostardeira/genética , Mostardeira/metabolismo , Peroxidase/metabolismo , Folhas de Planta/microbiologia , Necrose e Clorose das Plantas , Proteínas de Plantas/genética , Sinapis/genética , Sinapis/metabolismo
14.
Chemosphere ; 240: 124891, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574442

RESUMO

We investigated the effects of endophytes inoculation on ecological factors such as root morphology, rhizosphere soil properties, heavy metal speciation, and rhizosphere and endophytic bacterial communities and their role on phytoremediation. Indian mustards were grown for two months in V-contaminated soil with three treatments (control, inoculation with Serratia PRE01 or Arthrobacter PRE05). Inoculation with PRE01 and PRE05 increased organic matter content by 6.94% and 4.6% respectively and significantly increased bioavailability of heavy metals in rhizosphere soils. Despite the endophyte inocula failed to flourish as stable endophytes, they significantly affected the specific composition and diversity of endophytic bacterial communities in roots, with no significant effect on rhizosphere bacterial communities. The test strains could greatly increase plant growth promotion-related biomarkers in the endosphere, especially those associated with Pseudomonas and Microbacterium genera. PICRUSt analysis predicted high relative abundances of functional genes related to environmental information processing especially in the endophytic microbiota. More biomass production (12.0%-17.4%) and total metals uptake (24.2%-32.0%) were acquired in inoculated treatments. We conclude that endophyte PRE01 or PRE05 inoculation could effectively enhance phytoremediation of V-contaminated soil by improving the rhizosphere and endosphere microecology without causing any ecological damage.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Endófitos/crescimento & desenvolvimento , Mostardeira/metabolismo , Rizosfera , Poluentes do Solo/toxicidade , Vanádio/toxicidade , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Mostardeira/efeitos dos fármacos , Mostardeira/microbiologia , Desenvolvimento Vegetal/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Microbiologia do Solo , Poluentes do Solo/análise , Vanádio/análise
15.
Genomics ; 112(1): 749-763, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31095998

RESUMO

Chitinases belong to the group of Pathogenesis-related (PR) proteins that provides protection against fungal pathogens. This study presents the, genome-wide identification and characterization of chitinase gene family in two important oilseed crops B. juncea and C. sativa belonging to family Brassicaceae. We have identified 47 and 79 chitinase genes in the genomes of B. juncea and C. sativa, respectively. Phylogenetic analysis of chitinases in both the species revealed four distinct sub-groups, representing different classes of chitinases (I-V). Microscopic and biochemical study reveals the role of reactive oxygen species (ROS) scavenging enzymes in disease resistance of B. juncea and C. sativa. Furthermore, qRT-PCR analysis showed that expression of chitinases in both B. juncea and C. sativa was significantly induced after Alternaria brassicae infection. However, the fold change in chitinase gene expression was considerably higher in C. sativa compared to B. juncea, which further proves their role in C. sativa disease resistance to A. brassicae. This study provides comprehensive analysis on chitinase gene family in B. juncea and C. sativa and in future may serve as a potential candidate for improving disease resistance in B. juncea through transgenic approach.


Assuntos
Alternaria , Brassicaceae/genética , Quitinases/genética , Família Multigênica , Mostardeira/genética , Antioxidantes/metabolismo , Brassicaceae/enzimologia , Brassicaceae/microbiologia , Quitinases/química , Quitinases/classificação , Cromossomos de Plantas , Duplicação Gênica , Genoma de Planta , Modelos Moleculares , Mostardeira/enzimologia , Mostardeira/microbiologia , Filogenia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Estresse Fisiológico/genética , Sintenia , Transcrição Genética
16.
Physiol Plant ; 168(3): 601-616, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31145472

RESUMO

During the first 24 hours of infection, Alternaria brassicicola developmental parameters such as conidial germination, germ tubes and appressoria formation on each of the five mature Brassica juncea leaves, correlated with a leaf position showing stronger development of the pathogen on older leaves than on young ones. As a consequence of fungal development, the black spot disease was observed during 96 hours of infection on a macroscopic scale, as well as via confocal microscopy. Degradation of the chloroplast thylakoids and plastoglobule appearance during infection, followed by the decrease in chlorophyll a fluorescence parameters i.e. maximum quantum yield of PSII (Fv /Fm ), non-photochemical quenching (NPQ) and chlorophyll a:b ratio, have been observed. Also, after an initial increase of carbohydrates (glucose, fructose and sucrose), content far below the respective control values was found. The content of secondary metabolites such as flavonoids and glucosinolates increased in a leaf position-dependent manner in infected leaves, with a lower level in older leaves than in younger ones. Although, the total phenolic compounds (TPCs) content did not differ significantly in infected leaves compared to control leaves, TPCs level in both control and infected leaves was leaf position-dependent. To the best of our knowledge, this is the first report on leaf position-dependent effect on the B. juncea biochemical response to A. brassicicola infection.


Assuntos
Alternaria/patogenicidade , Morte Celular , Mostardeira/metabolismo , Mostardeira/microbiologia , Fotossíntese , Doenças das Plantas/microbiologia , Clorofila , Folhas de Planta/microbiologia , Metabolismo Secundário
17.
Int J Syst Evol Microbiol ; 70(5): 2972-2980, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31199229

RESUMO

Four Gram-stain-positive strains, R7T, R11, R19T and R27, were isolated from suan-tsai, a traditional fermented mustard green product of Taiwan. Cells were rod-shaped, non-motile, non-haemolytic, asporogenous, facultatively anaerobic, heterofermentative, and did not exhibit catalase and oxidase activities. Comparative analyses of 16S rRNA, pheS and rpoA gene sequences demonstrated that these novel strains were members of the genus Lactobacillus. 16S rRNA and the concatenated pheS and rpoA gene sequence similarities between strains R7T and R11, and strains R19T and R27 were very high (>99.8 % similarity), respectively. On the basis of 16S rRNA gene sequence similarities, the type strains of Lactobacillus paralimentarius (98.5 %), Lactobacillus kimchii (98.5 %), Lactobacillus alimentarius (98.1 %) and Lactobacillus bobalius (98.1 %) were the closest neighbours to strains R7T and R11, and the type strains of Lactobacillus brevis (98.9 %), Lactobacillus cerevisiae (98.4 %), Lactobacillus hammesii (98.4 %), Lactobacillus koreensis (98.4 %) and Lactobacillus yonginensis (98.0 %) were the closest neighbours to strains R19T and R27, respectively. The average nucleotide identity values of R7T and R19T with the closely related type strains were 78.9-80.1% and 75.7-80.5 %, respectively. The digital DNA-DNA hybridization values were 22.8-23.6% and 21.0-23.1 %, respectively. Phenotypic and genotypic test results demonstrated that these strains represent two novel species of the genus Lactobacillus, for which the name Lactobacillus suantsaicola sp. nov. (R7T=BCRC 81127T=NBRC 113530T) and Lactobacillus suantsaiihabitans sp. nov. (R19T=BCRC 81129T=NBRC 113532T) are proposed.


Assuntos
Alimentos e Bebidas Fermentados/microbiologia , Microbiologia de Alimentos , Lactobacillus/classificação , Mostardeira/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Lactobacillus/isolamento & purificação , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Taiwan
18.
Sci Rep ; 9(1): 17089, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31745129

RESUMO

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is a major disease of crop brassicas, with inadequate variation for resistance in primary gene pools. We utilized a wild Brassicaceae species with excellent resistance against stem rot to develop a set of B. juncea - B. fruticulosa introgression lines (ILs). These were assessed for resistance using a highly reproducible stem inoculation technique against a virulent pathogen isolate. Over 40% of ILs showed higher levels of resistance. IL-43, IL-175, IL-215, IL-223 and IL-277 were most resistant ILs over three crop seasons. Sequence reads (21x) from the three most diverse ILs were then used to create B. juncea pseudomolecules, by replacing SNPs of reference B. juncea with those of re-sequenced ILs. Genotyping by sequencing (GBS) was also carried out for 88 ILs. Resultant sequence tags were then mapped on to the B. juncea pseudomolecules, and SNP genotypes prepared for each IL. Genome wide association studies helped to map resistance responses to stem rot. A total of 13 significant loci were identified on seven B. juncea chromosomes (A01, A03, A04, A05, A08, A09 and B05). Annotation of the genomic region around identified SNPs allowed identification of 20 candidate genes belonging to major disease resistance protein families, including TIR-NBS-LRR class, Chitinase, Malectin/receptor-like protein kinase, defensin-like (DEFL), desulfoglucosinolate sulfotransferase protein and lipoxygenase. A majority of the significant SNPs could be validated using whole genome sequences (21x) from five advanced generation lines being bred for Sclerotinia resistance as compared to three susceptible B. juncea germplasm lines. Our findings not only provide critical new understanding of the defensive pathway of B. fruticulosa resistance, but will also enable development of marker candidates for assisted transfer of introgressed resistant loci in to agronomically superior cultivars of crop Brassica.


Assuntos
Ascomicetos/patogenicidade , Cromossomos de Plantas/genética , Resistência à Doença/genética , Genes de Plantas/genética , Mostardeira/genética , Doenças das Plantas/genética , Polimorfismo de Nucleotídeo Único , Mapeamento Cromossômico , Testes Genéticos , Genoma de Planta , Infecções/genética , Infecções/microbiologia , Mostardeira/imunologia , Mostardeira/microbiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Locos de Características Quantitativas
19.
Environ Sci Pollut Res Int ; 26(32): 32815-32823, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502049

RESUMO

Iron (Fe) is one of the essential micronutrients for all living organisms. Despite its abundance in most of the contaminated soil, it is usually in unavailable forms. The unavailable form of Fe could be mobilized to plants by the use of microorganisms. This study was carried out to show that the Fe-contaminated field soils could be used to accumulate Fe in the plant parts using bacterial inoculation. For this, from a set of bacterial isolates, four Fe-tolerant bacteria were selected and identified based on 16S rRNA gene sequencing. The Fe-tolerant bacteria belonged to the genus Bacillus toyonensis (MG430287), Rhodococcus hoagii (MG432495), Lysinibacillus mangiferihumi (MG432492), and Lysinibacillus fusiformis (MG430290). Screening of plant growth-promoting properties of these isolates revealed that all isolates were able to produce indole acetic acid (50.0-84.0 µg/ml), siderophore, and potassium solubilization (except R. hoagii). Pot assay using Fe-contaminated ((8.07-8.35 g kg-1) soils River Directorate of India) revealed that Fe-tolerant bacteria enhanced the growth of Brassica juncea and its biomass. Besides the improved plant growth, the inoculated plants also showed an overall percentage increase in the uptake of iron in root, stem, and leaf (57.91-128.31%) compared with uninoculated plants. In addition to enhanced plant growth attributes, the isolates also improved the total chlorophyll content and antioxidant properties such as total phenol, proline, and ascorbic acid oxidase. Thus, the results clearly indicated that these isolates could be used as a bioinoculant to improve the sequestration of Fe from the contaminated soils and alleviation of Fe stress in plants.


Assuntos
Biodegradação Ambiental , Mostardeira/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/análise , Bacillus/genética , Bactérias/genética , Biomassa , Índia , Ácidos Indolacéticos , Ferro , Mostardeira/microbiologia , Desenvolvimento Vegetal , RNA Ribossômico 16S/genética , Sideróforos , Solo
20.
Mol Plant Microbe Interact ; 32(12): 1598-1613, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31364484

RESUMO

Alternaria blight, caused by Alternaria brassicae, causes considerable yield loss in Brassica crops. While several blight-resistant varieties have been developed using resistance sources from host germplasm, none of them are entirely successful in imparting durable resistance. This has prompted the exploration of novel gene pools of nonhost plant species. Nonhost resistance (NHR) is a durable form of resistance, comprising pre- and postinvasion layers of defense. We aimed to identify the molecular basis of NHR to A. brassicae and identify the layers of NHR operating in a nonhost, chickpea (Cicer arietinum). To elucidate the layers of NHR operating against A. brassicae, we compared the histopathology and infection patterns of A. brassicae in C. arietinum and Brassica juncea. Delayed conidial germination, impeded hyphal growth, suppressed appressorium formation, and limited hyphal penetration occurred in the nonhost plant compared with the host plant, implying the involvement of the preinvasion layer of NHR in C. arietinum. Next, we investigated the molecular basis of robust NHR, in C. arietinum challenged with A. brassicae, by microarray-based global transcriptome profiling. Genes involved in stomatal closure, cuticular wax biosynthesis, cell-wall modification, and secondary metabolite production (contributing to preinvasion NHR) as well as reactive oxygen species (ROS) and cell death (contributing to postinvasion NHR) were found to be upregulated. Consistent with transcriptomic analysis, the morpho-pathological analysis revealed stomatal closure, ROS accumulation, and localized cell death in C. arietinum as the defense strategies against A. brassicae. Thus, we identified NHR-contributing genes with potential applications in blight resistance gene transfer to B. juncea.


Assuntos
Alternaria , Cicer , Resistência à Doença , Transcriptoma , Alternaria/fisiologia , Cicer/microbiologia , Resistência à Doença/genética , Perfilação da Expressão Gênica , Mostardeira/genética , Mostardeira/microbiologia
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