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Maize is the third most vital global cereal, playing a key role in the world economy and plant genetics research. Despite its leadership in production, maize faces a severe threat from banded leaf and sheath blight, necessitating the urgent development of eco-friendly management strategies. This study aimed to understand the resistance mechanisms against banded leaf and sheath blight (BLSB) in maize hybrid "Vivek QPM-9". Seven fungicides at recommended doses (1000 and 500 ppm) and two plant defense inducers, salicylic acid (SA) and jasmonic acid (JA) at concentrations of 50 and 100 ppm, were applied. Fungicides, notably Azoxystrobin and Trifloxystrobin + Tebuconazole, demonstrated superior efficacy against BLSB, while Pencycuron showed limited effectiveness. Field-sprayed Azoxystrobin exhibited the lowest BLSB infection, correlating with heightened antioxidant enzyme activity (SOD, CAT, POX, ß-1,3-glucanase, PPO, PAL), similar to the Validamycin-treated plants. The expression of defense-related genes after seed priming with SA and JA was assessed via qRT-PCR. Lower SA concentrations down-regulated SOD, PPO, and APX genes but up-regulated CAT and ß-1,3-glucanase genes. JA at lower doses up-regulated CAT and APX genes, while higher doses up-regulated PPO and ß-1,3-glucanase genes; SOD gene expression was suppressed at both JA doses. This investigation elucidates the effectiveness of certain fungicides and plant defense inducers in mitigating BLSB in maize hybrids and sheds light on the intricate gene expression mechanisms governing defense responses against this pathogen.
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Genetic diversity in Sclerotium rolfsii is useful for understanding its population structure, identifying different mycelial compatibility groups (MCGs), and developing targeted strategies for disease management in affected crops. In our study, a comprehensive genetic analysis was conducted on 50 isolates of S. rolfsii, collected from various geographic regions and host plants. Two specific genes, TEF1α and RPB2, were utilized to assess the genetic diversity and relationships among these isolates. Notably, out of 1225 pairings examined, only 154 exhibited a compatible reaction, while the majority displayed antagonistic reactions, resulting in the formation of a barrier zone. The isolates were grouped into 10 distinct MCGs. These MCGs were further characterized using genetic sequencing. TEF1α sequences distinguished the isolates into 17 distinct clusters, and RPB2 sequences classified them into 20 clusters. Some MCGs shared identical gene sequences within each gene, while others exhibited unique sequences. Intriguingly, when both TEF1α and RPB2 sequences were combined, all 10 MCGs were effectively differentiated, even those that appeared identical with single-gene analysis. This combined approach provided a comprehensive understanding of the genetic diversity and relationships among the S. rolfsii isolates, allowing for precise discrimination between different MCGs. The results shed light on the population structure and genetic variability within this plant pathogenic fungus, providing valuable insights for disease management and control strategies. This study highlights the significance of comprehending the varied virulence characteristics within S. rolfsii isolates, categorizing them into specific virulence groups based on disease severity index (DSI) values. The association with MCGs provides additional insights into the genetic underpinnings of virulence in this pathogen. Furthermore, the identification of geographical patterns in virulence implies the influence of region-specific factors, with potential implications for disease control and crop protection strategies.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [G. M. Sandeep] Last name [Kumar]. Author 2 Given name: [Praveen Kumar] Last name [Singh]. Also, kindly confirm the details in the metadata are correct.I confirm that the given names are accurate and presented in the correct sequence.
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Basidiomycota , Variação Genética , Tipagem de Sequências Multilocus , Filogenia , Doenças das Plantas , Doenças das Plantas/microbiologia , Basidiomycota/genética , Basidiomycota/isolamento & purificação , Basidiomycota/classificação , Micélio/genética , Proteínas Fúngicas/genética , DNA Fúngico/genética , Produtos Agrícolas/microbiologiaRESUMO
Rice remains the primary staple for more than half of the world's population, yet its cultivation faces numerous challenges, including both biotic and abiotic stresses. One significant obstacle is the prevalence of rice blast disease, which substantially diminishes productivity and increases cultivation costs due to frequent fungicide applications. Consequently, the presence of fungicide residues in rice raises concerns about compliance with international maximum residue limits (MRLs). While host resistance has proven effective, it often remains vulnerable to new variants of the Magnaporthe oryzae pathogen. Therefore, there is a critical need to explore innovative management strategies that can complement or enhance existing methods. An unexplored avenue involves harnessing endophytic bacterial communities. To this end, the present study investigates the potential of eleven endophytic Bacillus spp. in suppressing Pyricularia oryzae, promoting plant growth, and eliciting a defense response through phyllobacterization. The results indicate that the secreted metabolome and volatilome of seven tested isolates demonstrate inhibitory effects against P.oryzae, ranging from a minimum of 40% to a maximum of 70%. Bacillus siamensis L34, B. amyloliquefaciens RA37, B. velezensis L12, and B. subtilis B18 produce antifungal antibiotics targeting P.oryzae. Additionally, B. subtilis S4 and B. subtilis S6 emerge as excellent inducers of systemic resistance against blast disease, as evidenced by elevated activity of biochemical defense enzymes such as peroxidase, polyphenol oxidase, and total phenol content. However, a balance between primary metabolic activity (e.g., chlorophyll content, chlorophyll fluorescence, and photosynthetic rate) and defense activity is observed. Furthermore, specific endophytic Bacillus spp. significantly stimulates defense-related genes, including OsPAD4, OsFMO1, and OsEDS1. These findings underscore the multifaceted potential of endophytic Bacillus in managing blast disease through antibiosis and induced systemic resistance. In conclusion, this study highlights the promising role of endophytic Bacillus spp. as a viable option for blast disease management. Their ability to inhibit the pathogen and induce systemic resistance makes them a valuable addition to the existing strategies. However, it is crucial to consider the trade-off between primary metabolic activity and defense response when implementing these bacteria-based approaches.
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Fungicidas Industriais , Oryza , Antibiose , Bactérias , Clorofila/metabolismo , Resistência à Doença/genética , Firmicutes , Fungicidas Industriais/farmacologia , Magnaporthe , Oryza/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/metabolismo , Resistência Sistêmica Adquirida da PlantaRESUMO
Maize brown sheath spot (MBSS), a new disease of maize, was discovered while surveying for maize leaf and sheath blight diseases in the Indian states of Assam, Jharkhand, Meghalaya, Manipur, and Odisha. Maize is the third most important cereal after rice and wheat in India. Unlike banded leaf and sheath blight disease caused by Rhizoctonia solani, MBSS symptoms on maize were discrete and limited to sheaths only. Symptoms of MBSS in the field were initially water-soaked necrotic lesions of 1 to 2 cm in diameter on the lowermost leaf sheaths, which then progressed to the upper sheaths. Lesions coalesced and covered approximately 2 to 5% of the sheath area. Infected dried lower leaves were shed, whereas infected upper leaves remained on the stem. The pathogen was isolated, characterized morphologically, pathologically, and molecularly, and identified as Waitea circinata var. prodigus, a basidiomycete known to cause basal leaf blight of seashore paspalum. The internal transcribed spacer (ITS) sequence 2 (ITS2) of rDNA from MBSS isolates formed a well supported clade with known W. circinata var. prodigus isolates. Molecular morphometric analysis of the ITS2 regions of the five known varieties of W. circinata detected distinguishing variations in GC content, compensatory base changes (CBCs), hemi- CBCs, indels, and altered base-pairing of helices. Variation in these characteristics may indicate that varieties are distinct biological species within W. circinata sensu lato. The geographical distribution and potential impacts of MBSS on the maize crop in India necessitate further investigations of pathogen identification and disease management.
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Basidiomycota , Zea mays , Índia , Doenças das Plantas/genética , Zea mays/genéticaRESUMO
Dark brown necrotic lesions caused by Magnaporthe oryzae on rice foliage is a contrasting microhabitat for leaf-colonizing microbiome as compared with the surrounding healthy chlorophyll-rich tissues. We explored culturable bacterial communities of blast lesions by adopting microbiological tools for isolating effective biocontrol bacterial strains against M. oryzae. 16S rRNA gene sequencing-based molecular identification revealed a total of 17 bacterial species belonging to Achromobacter (2), Comamonas (1), Curtobacterium (1), Enterobacter (1), Leclercia (2), Microbacterium (1), Pantoea (3), Sphingobacterium (1), and Stenotrophomonas (5) found colonizing the lesion. Over 50% of the bacterial isolates were able to suppress the mycelial growth of M. oryzae either by secretory or volatile metabolites. Volatiles released by Achromobacter sp., Curtobacterium luteum, Microbacterium oleivorans, Pantoea ananatis, Stenotrophomonas maltophilia, and Stenotrophomonas sp., and were found to be fungicidal while others showed fungistatic action. In planta pathogen challenged evaluation trial revealed the biocontrol potential of Stenotrophomonas sp. and Microbacterium oleivorans that showed over 60% blast severity suppression on the rice leaf. The lesion-associated bacterial isolates were found to trigger expression of defense genes such as OsCEBiP, OsCERK1, OsEDS1, and OsPAD4 indicating their capability to elicit innate defense in rice against blast disease. The investigation culminated in the identification of potential biocontrol agents for the management of rice blast disease.
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Magnaporthe , Oryza , Actinobacteria , Ascomicetos , Magnaporthe/genética , Pantoea , Doenças das Plantas , RNA Ribossômico 16S/genéticaRESUMO
Fungal diseases posing a severe threat to the production of pulses, a major protein source, necessitates the need of new highly efficient antifungal agents. The present study was aimed to develop azomethine based nano-fungicides for protecting the crop from fungal pathogens and subsequent yield losses. The protocol for the formation of nano-azomethines was generated and standardized. Technically pure azomethines were transformed into their nano-forms exploiting polyethylene glycol as the surface stabilizer. Characterization was performed by optical (imaging) probe (Zetasizer) and electron probe (TEM) characterization techniques. The mean particle sizes of all nano-fungicides were below 100nm. In vitro fungicidal potential of nano-chemicals was increased by 2 times in comparison to that of conventional sized azomethines against pathogenic fungi, namely, Rhizoctonia solani, Rhizoctonia bataticola and Sclerotium rolfsii. The performance of nano-chemicals in pot experiment study was also superior to conventional ones as antifungal agent.
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Compostos Azo/química , Compostos Azo/toxicidade , Basidiomycota/efeitos dos fármacos , Fungicidas Industriais/química , Fungicidas Industriais/toxicidade , Rhizoctonia/efeitos dos fármacos , Tiossemicarbazonas/química , Tiossemicarbazonas/toxicidade , Basidiomycota/citologia , Micelas , Nanopartículas/química , Nanopartículas/toxicidade , Nanopartículas/ultraestrutura , Nanotecnologia , Polietilenoglicóis/química , Polietilenoglicóis/toxicidade , Rhizoctonia/citologiaRESUMO
Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hexaconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.
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Antifúngicos/farmacologia , Cianobactérias/metabolismo , Ácidos Indolacéticos/metabolismo , Nanopartículas , Fixação de Nitrogênio/efeitos dos fármacos , Triazóis/farmacologia , Antifúngicos/química , Triazóis/químicaRESUMO
The study was aimed to develop a nano form of an existing fungicide for improving plant protection and reducing crop losses caused by fungal pathogens. The protocol for the preparation and estimation of nanohexaconazole was developed. Technically pure hexaconazole was converted into its nanoform using polyethyleneglycol-400 (PEG) as the surface stabilizing agent. Nanohexaconazole was characterized using Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS) studies. The average particle size of nanohexaconazole was about 100 nm. An analytical method was also developed for quality control of the nanofungicide by GLC fitted with flame ionization detector. Its limit of detection was 2.5 ppm. Fungicidal potential of nanohexaconazole was better in comparison to that of conventional hexaconazole. Hydrolytic and thermal stability studies confirmed its stability at par with the conventional formulation of fungicide. Impact of nanohexaconazole on soil nitrifiers was tested in vitro and there were no significant adverse effect in their numbers observed as compared to conventional registered formulation, proving the safety of the nanofungicide.
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Composição de Medicamentos/normas , Nanopartículas/administração & dosagem , Nitrobacter/efeitos dos fármacos , Nitrosomonas/efeitos dos fármacos , Triazóis/administração & dosagem , Triazóis/síntese química , Sobrevivência Celular/efeitos dos fármacos , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/síntese química , Fungicidas Industriais/toxicidade , Índia , Teste de Materiais , Nanopartículas/química , Nanopartículas/toxicidade , Nitrificação/fisiologia , Nitrobacter/fisiologia , Nitrosomonas/fisiologia , Tamanho da Partícula , Controle de Qualidade , Microbiologia do Solo , Triazóis/toxicidadeRESUMO
A comparative study on residues and rate of dissipation of a new nanoformulation of pyridalyl and commercial pyridalyl was carried out on okra under net house and field conditions. Okra crop was sprayed with commercial and nanoformulation of pyridalyl at recommended (75 g a. i./ha) and double the recommended dose (150 g a. i./ha) at the time of fruiting. Quantitation of residues of pyridalyl in okra was done by ultra high performance liquid chromatography over a period of 15 days, and recovery of the method ranged from 79 to 87 %. The half life calculated from the dissipation pattern of pyridalyl on okra for commercial and developed nanoformulation proved that residues of nanopyridalyl did not persist much longer than that of conventional formulation in net house as well as in field trials. The risk quotient value of pyridalyl in okra was significantly lower than 1, implying its negligible risk to the humans.
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Abelmoschus/química , Nanoestruturas/análise , Resíduos de Praguicidas/análise , Éteres Fenílicos/análise , Monitoramento Ambiental , Frutas/química , Meia-Vida , Inseticidas/análiseRESUMO
A study was undertaken to evaluate the decline of the residues of pyridalyl in tomatoes grown in two different cultivation systems: open field (conventional cultivation) and net house (pot experiment). Field experiment was conducted with commercial (10 EC) and nanoformulation of pyridalyl on tomato crop. Tomato plants were subjected to pesticide spray, when fruits were close to ripeness. Fruit samples were taken periodically and cleaned up using QuEChERS methodology, and the residue of pyridalyl was analyzed by ultrahigh-performance liquid chromatography (UHPLC). It dissipated in tomato fruit following the first-order kinetics. In field, average initial deposit of pyridalyl in tomato was observed to be 0.222 and 0.371 µg g(-1) at recommended and double the recommended application rate, respectively, using nanoformulation while it was 0.223 and 0.393 µg g(-1) on using commercial formulation, respectively. The half-life (t1/2) value of nanopyridalyl in tomato fruit was 2.8 and 3.2 days while for commercial formulation, it was 2.5 and 2.6 days for recommended and double the recommended dose, respectively. In India, maximum residue limit (MRL) on tomato has not been fixed for pyridalyl but its residues were always below European MRLs (5 µg g(-1)) on tomato at both application rates. The results of terminal residue showed that pyridalyl residues were below the available MRL. Low residues in tomatoes suggested that this pesticide is safe to use under the recommended dosage. No statistical differences were observed between the cultivation systems in relation to the residue levels of pyridalyl.
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Monitoramento Ambiental/métodos , Resíduos de Praguicidas/análise , Éteres Fenílicos/análise , Solanum lycopersicum/química , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental/estatística & dados numéricos , Frutas/química , Meia-Vida , Índia , CinéticaRESUMO
In order to identify the most suitable method for the estimation of nanosulfur for studying its residue dynamics, the present work was taken up. HPLC and GC methods were explored for its analysis. A comparative study of the existing analytical methods for the quality control of nanosulfur was undertaken. UV spectrophotometry and HPLC methods were superior with lower LOD when compared to GC-MS, which was not satisfactory due to breakage of catenated S20 into S6 and S8 . The method has been validated by analyzing various nanosulfur formulations of known concentrations. The recovery of the UV and HPLC methods ranged from 80.71 to 109.51% and 82.31 to 109.84%, respectively. The LOD of UV, GC-MS, and HPLC is 4, 20, and 1 ppm, respectively. The retention time of sulfur was 13.77 (HPLC), 2.89 (ultra high performance liquid chromatography), and 12.715 + 21.524 min (GC-MS). The method was successfully utilized for estimating sulfur in natural samples such as water from a sulfur hot spring and wastewater. The method has been validated by following the method recommended by the American Society for Testing and Materials. The HPLC method emerged as the best analytical method for the estimation of elemental sulfur.
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Nanoestruturas/análise , Nascentes Naturais/química , Enxofre/análise , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Espectrofotometria UltravioletaRESUMO
In mango pickle industry, a significant quantity of mango seed kernels is discarded as solid wastes. These seed kernels can be an ideal source for obtaining extracts rich in bioactive polyphenolic compounds with good antioxidant properties. The potential of mango kernel phenolic extract (MKPE) was investigated as a natural and effective antimicrobial agent for controlling major postharvest fungal pathogen infections, a significant threat to global food supply chains. Fungal pathogens contribute to the deterioration of fruits, vegetables, and grains during storage and transportation, leading to economic losses and compromised food safety. MKPE was obtained from pickling variety 'Ramkela' raw mango kernels, and its phenolic composition was characterized using LC-MS. The in vitro antifungal activity of MKPE against Botrytis cinerea, Colletotrichum gloeosporoides, and Rhizopus stolonifer was evaluated in vitro. A concentration-dependent inhibition of fungal radial growth against all three pathogens was observed, exhibiting the potential of MKPE as a valuable natural resource for addressing postharvest losses caused by fungal pathogens. The extraction process yielded a total phenolic content of 2128 mg GAE/100 g. Major polyphenolic bioactive compounds present were mangiferin, quercetin, and rhamnetin. The in-vitro antimicrobial assay showed reduction in the radial growth and inhibition percent of the pathogens. EC50 values of MKPE for B. cineria, C. gloeosporoides, and R. stolonifer was found to 364.17, 963.8 and 926 ppm, respectively. Our results demonstrate an economical, sustainable, and eco-friendly approach to manage post-harvest diseases rendered by fungi using mango MKPE from pickling industry waste.
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Twenty-two eco-friendly, novel Schiff bases were synthesized from 2,4,5-trichloro aniline and characterized by using FT-IR, 1H NMR, and 13C NMR techniques. Fungicidal activity against pathogenic fungi Sclerotium rolfsii and Rhizoctonia bataticola and insecticidal activity against the stored grain insect pest Callosobruchus maculatus of the test compounds were evaluated under control condition. All of the investigated compounds, according to the study, exhibited moderate to good antifungal and insecticidal activities. The best antifungal activity against both pathogenic fungi was demonstrated by C15 and C16 whose ED50 values were recorded 11.4 and 10.4 µg/mL against R. bataticola and 10.6 and 11.9 µg/mL against S. rolfsii, respectively. They were further screened in for disease suppression against both pathogenic fungi under pot condition through different methods of applications in green gram (Vigna radiata L.) crop. The compounds C10 and C18 had the highest insecticidal activity, with LD50 values of 0.024 and 0.042 percentages, respectively. Stepwise regression analysis using root mean square error (RMSE) and correlation coefficient (R) method used to validate the quantitative structure activity relationship (QSAR) of synthesized compounds in addition to their fungicidal and insecticidal actions. To the best of our knowledge, this investigation on the 22 new Schiff bases as possible agrochemicals is the first one that has been fully reported.
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Maydis leaf blight is a significant disease of maize caused by Bipolaris maydis race T, O and C. Molecular mechanisms regulating defense responses in non-CMS maize towards race O fungus are not fully known. In the present investigation, comparative transcriptome profiling was conducted on a highly resistant maize genotype SC-7-2-1-2-6-1 against a standard susceptible variety CM 119 at 48 h post inoculation (h PI) along with non-infected control. mRNA sequencing generated 38.4 Gb data, where 9349602 reads were mapped uniquely in SC-7, whereas 2714725 reads were mapped uniquely in CM-119. In inoculated SC-7, the total number of differentially expressed genes (DEGs) against control was 1413, where 1011 were up-regulated, and 402 were down-regulated. In susceptible inoculated genotype CM 119, the number of DEGs against control was 2902, where 1703 were up-, and 1199 were down-regulated. DEGs between inoculated resistant and susceptible genotypes were 10745, where 5343 were up-, and 5402 were down-regulated. The RNA-seq data were validated using RT-qPCR. The key findings are that SC-7 poses a robust plant signaling system mainly induced by oxidation-reduction process and calcium-mediated signaling. It regulates its fitness-related genes efficiently, viz., aldolase 2 gene, isopropanoid, phyto hormones, P450 cytochrome, amino acid synthesis, nitrogen assimilation genes etc. These findings showed more transcriptional changes in the SC-7 genotype, which contains many defence-related genes. They can be explored in future crop development programmes to combat multiple maize diseases. The current finding provides information to elucidate molecular and cellular processes occurring in maize during B. maydis race O infection.
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Sustainable food production is necessary to meet the demand of the incessantly growing human population. Phytopathogens pose a major constraint in food production, and the use of conventional fungicides to manage them is under the purview of criticism due to their numerous setbacks. In the present study, essential oil-grafted copper nanoparticles (EGC) were generated, characterized, and evaluated against the maize fungal pathogens, viz., Bipolaris maydis, Rhizoctonia solani f. sp. sasakii, Macrophomina phaseolina, Fusarium verticillioides, and Sclerotium rolfsii. The ED50 for the fungi under study ranged from 43 to 56 µg ml-1, and a significant inhibition was observed at a low dose of 20 µg ml-1 under in vitro conditions. Under net house conditions, seed treatment + foliar spray at 250 and 500 mg L-1 of EGC performed remarkably against maydis leaf blight (MLB), with reduced percent disease index (PDI) by 27.116 and 25.292%, respectively, in two Kharif seasons (May-Sep, 2021, 2022). The activity of enzymatic antioxidants, viz., ß-1, 3-glucanase, PAL, POX, and PPO, and a non-enzymatic antioxidant (total phenolics) was increased in treated maize plants, indicating host defense was triggered. The optimum concentrations of EGC (250 mg L-1 and 500 mg L-1) exhibited improved physiological characteristics such as photosynthetic activity, shoot biomass, plant height, germination percentage, vigor index, and root system traits. However, higher concentrations of 1,000 mg L-1 rendered phytotoxicity, reducing growth, biomass, and copper bioaccumulation to high toxic levels, mainly in the foliar-sprayed maize leaves. In addition, EGC and copper nanoparticles (CuNPs) at 1,000 mg L-1 reduced the absorption and concentration of manganese and zinc indicating a negative correlation between Cu and Mn/Zn. Our study proposes that the CuNPs combined with EO (Clove oil) exhibit astounding synergistic efficacy against maize fungal pathogens and optimized concentrations can be used as an alternative to commercial fungicides without any serious impact on environmental health.
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Plant growth-promoting endophytic microbes have drawn the attention of researchers owing to their ability to confer fitness benefits in many plant species. Here, we report agriculturally beneficial traits of rice-leaf-adapted endophytic Microbacterium testaceum. Our polyphasic taxonomic investigations revealed its identity as M. testaceum. The bacterium displayed typical endophytism in rice leaves, indicated by the green fluorescence of GFP-tagged M. testaceum in confocal laser scanning microscopy. Furthermore, the bacterium showed mineral solubilization and production of IAA, ammonia, and hydrolytic enzymes. Tobacco leaf infiltration assay confirmed its non-pathogenic nature on plants. The bacterium showed antifungal activity on Magnaporthe oryzae, as exemplified by secreted and volatile organic metabolome-mediated mycelial growth inhibition. GC-MS analysis of the volatilome of M. testaceum indicated the abundance of antimicrobial compounds. Bacterization of rice seedlings showed phenotypic traits of MAMP-triggered immunity (MTI), over-expression of OsNPR1 and OsCERK, and the consequent blast suppressive activity. Strikingly, M. testaceum induced the transcriptional tradeoff between physiological growth and host defense pathways as indicated by up- and downregulated DEGs. Coupled with its plant probiotic features and the defense elicitation activity, the present study paves the way for developing Microbacterium testaceum-mediated bioformulation for sustainably managing rice blast disease.
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Bipolaris maydis is pathogen of maize which causes maydis leaf blight disease. In India major losses occur due to the B. maydis race "O" pathogen, whereas in other parts of the world, major losses are due to the race "T" pathogen. In the present study, we conducted an in planta transcriptomics study of the B. maydis race "O" pathogen after infection on non-CMS maize resistant and susceptible genotypes by mRNA sequencing to understand the molecular basis of pathogenicity for better management of the pathogen. Approximately 23.4 GB of mRNA-seq data of B. maydis were obtained from both resistant and susceptible maize backgrounds for fungus. Differentially expressed genes (DEGs) analysis of B. maydis in two different genetic backgrounds suggested that the majority of highly DEGs were associated with mitochondrial, cell wall and chitin synthesis, sugar metabolism, peroxidase activity, mitogen-activated protein kinase (MAPK) activity, and shikimate dehydrogenase. KEGG analysis showed that the biosynthetic pathways for secondary metabolism, antibiotics, and carbon metabolism of fungus were highly enriched, respectively, in susceptible backgrounds during infection. Previous studies in other host pathogen systems suggest that these genes play a vital role in causing disease in their host plants. Our study is probably the first transcriptome study of the B. maydis race "O" pathogen and provides in-depth insight of pathogenicity on the host.
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Tilletia indica is a quarantine fungal pathogen that poses a serious biosecurity threat to wheat-exporting countries. Acquiring genetic data for the pathogenicity characters of T. indica is still a challenge for wheat breeders and geneticists. In the current study, double digest restriction-site associated-DNA genotyping by sequencing was carried out for 39 T. indica isolates collected from different locations in India. The generated libraries upon sequencing were with 3,346,759 raw reads on average, and 151 x 2 nucleotides read length. The obtained bases per read ranged from 87 Mb in Ti 25 to 1,708 Mb in Ti 39, with 505 Mb on average per read. Trait association mapping was performed using 41,473 SNPs, infection phenotyping data, population structure, and Kinship matrix, to find single nucleotide polymorphisms (SNPs) linked to virulence genes. Population structure analysis divided the T. indica population in India into three subpopulations with genetic mixing in each subpopulation. However, the division was not in accordance with the degree of virulence. Trait association mapping revealed the presence of 13 SNPs associated with virulence. Using sequences analysis tools, one gene (g4132) near a significant SNP was predicted to be an effector, and its relative expression was assessed and found upregulated upon infection.
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In spite of modern crop protection measures, the overall crop losses due to pests and pathogens are huge. Rhizoctonia solani, Macrophomina phaseolina, Sclerotium rolfsii, and Fusarium oxysporum are one of the most devastating soil-borne fungi and cause numerous plant diseases. Therefore, the present study aimed to systematically design and develop new nanofungicides based on imidazole drugs, clotrimazole, econazole nitrate, and miconazole nitrate, for effective and efficient management of plant diseases. The assessment of these antifungal medicines for their fungicide likeness using Hao's rule and their enzyme inhibitory potential by molecular docking was helpful in ensuring their utility as antifungal agents in managing phytopathogenic fungi. Nanotechnological strategies were used to develop nanoformulations of test compounds in poly(ethylene glycol) 300 for further augmenting their bioactivity. Transmission electron microscopy studies confirmed the nanosize of the prepared products. Analysis of their in vitro and in vivo antifungal properties revealed their usefulness in controlling the test fungi, R. solani, M. phaseolina, S. rolfsii, and F. oxysporum. Excellent in vitro antifungal activities were displayed by the clotrimazole nanoformulation with a median effective dose (ED50) of 1.18 µg/mL against R. solani, the econazole nitrate nanoformulation with an ED50 of 5.25 µg/mL against S. rolfsii, and the miconazole nitrate nanoformulation with an ED50 of 1.49 and 1.82 µg/mL against M. phaseolina and F. oxysporum. Furthermore, in vivo studies against test fungi demonstrated the antifungal potency of all the nanoformulations with disease incidences ranging from 11.11 to 27.38% in plants treated with nanoformulations of test chemicals as compared to the inoculated control (39.68-72.38%).
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Fungicidas Industriais/farmacologia , Imidazóis/farmacologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/crescimento & desenvolvimento , Avaliação de Medicamentos , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Imidazóis/química , Simulação de Acoplamento Molecular , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimentoRESUMO
The biocontrol efficacy of a cyanobacterium Calothrix elenkinii (Ce), silver nanoparticles (AgNPs) and their augmented complex (AgNPs-Ce) was evaluated. Foliar application of AgNPs-Ce reduced the disease severity by 47-58%, along with significant increases of 44-45%, 40-46% and 23-33% in leaf chlorophyll, carotenoid content, and polyphenol oxidase activity in the A. alternata infected tomato plants. A significant reduction in the pathogen load was recorded, both by plate counts and microscopic observations in the AgNPs, Ce and AgNPs-Ce treatments, while AgNPs-Ce also effectively reduced ergosterol content by 63-79%. Amplification using PCR-ITS primers revealed very faint bands or none in the AgNPs-Ce treated leaves, illustrating the inhibition of fungal growth. Significantly higher yield was recorded in the pathogen challenged plants receiving AgNPs-Ce, AgNPs, and Ce treatments. Higher expression of elicited antioxidant enzymes, along with enhanced plant growth attributes and lowered fungal load highlight the biocontrol potential of AgNPs-Ce treatment in A. alternata infected plants. This synergistic association can be explored as a promising biocontrol option against A. alternata challenged tomato plants under various agroclimatic conditions.