RESUMO
Endophytes stimulate plant growth and inhibit phytopathogens. Most of the known endophytes are host-specific and only a few strains are effective for practical field use. Thus, this study focuses on the evaluation of endophytes viz., Bacillus pseudomycoides strain HP3d, Paenibacillus polymyxa strain PGSS1, B. velezensis strain A6 and P42 isolated from diverse crop ecosystems for their potential to promote plant growth and induce systemic resistance against sheath blight disease in rice. The endophytes were studied for plant growth promoting traits in vivo conditions and were found to exhibit ammonia (light to strong), siderophore (yellow zone on the CAS agar plate), indole-3-acetic acid (15.20-22.19 µg mL-1) production and phosphorus solubilization (1.2-1.5 cm). In the glasshouse, when applied individually and in combinations through various methods like seed treatment, seedling dip, and foliar spray these endophytes significantly reduced lesion size (2.06-2.37 fold) and ShB severity (2.60-2.58 fold), enhancing growth parameters viz., shoot (1.09-1.11 fold), root (1.02-1.20 fold), number of tillers (1.2-1.6 fold), shoot (80.58-82.64 %) and root (62.01-66.66 %) dry matter over untreated control. Consequently, enzyme activity viz., polyphenol oxidase (2.20-3.00 U-1min-1g-1), peroxidase (0.31-0.35 min-1g-1), superoxide dismutase (118.50-123.00 Ug-1 FW), and phenylalanine ammonia lyase (0.84-0.90 minâ»1gâ»1FW) was found to increase up to the fourth day after the pathogen challenge and subsequently decrease thereafter. Chlorophyll content post inoculation of ShB declined over time but endophyte treated plants exhibited lesser reductions over uninoculated control. Field trials corroborated the in vitro findings, demonstrating reduced ShB (1.71-1.88 fold decrease in PDI) and enhanced growth (1.1-1.2 fold increase in shoot length) over untreated controls. The combined application of seedling dip, seed treatment, and foliar spray proved to be the most optimum treatment. The findings highlight the potential of diverse crop-derived endophytes, emphasizing their non-host specificity and effectiveness as broad-spectrum bioagents in actual field conditions.
RESUMO
Bacillus thuringiensis is the most widely used biopesticide, targets a diversity of insect pests belonging to several orders. However, information regarding the B. thuringiensis strains and toxins targeting Zeugodacus cucurbitae is very limited. Therefore, in the present study, we isolated and identified five indigenous B. thuringiensisstrains toxic to larvae of Z. cucurbitae. However, of five strains NBAIR BtPl displayed the highest mortality (LC50 = 37.3 µg/mL) than reference strain B. thuringiensis var. israelensis (4Q1) (LC50 = 45.41 µg/mL). Therefore, the NBAIR BtPl was considered for whole genome sequencing to identify the cry genes present in it. Whole genome sequencing of our strain revealed genome size of 6.87 Mb with 34.95% GC content. Homology search through the BLAST algorithm revealed that NBAIR BtPl is 99.8% similar to B. thuringiensis serovar tolworthi, and gene prediction through Prokka revealed 7406 genes, 7168 proteins, 5 rRNAs, and 66 tRNAs. BtToxin_Digger analysis of NBAIR BtPl genome revealed four cry gene families: cry1, cry2, cry8Aa1, and cry70Aa1. When tested for the presence of these four cry genes in other indigenous strains, results showed that cry70Aa1 was absent. Thus, the study provided a basis for predicting cry70Aa1 be the possible reason for toxicity. In this study apart from novel genes, we also identified other virulent genes encoding zwittermicin, chitinase, fengycin, and bacillibactin. Thus, the current study aids in predicting potential toxin-encoding genes responsible for toxicity to Z. cucurbitae and thus paves the way for the development of B. thuringiensis-based formulations and transgenic crops for management of dipteran pests.
Assuntos
Bacillus thuringiensis , Proteínas de Bactérias , Genoma Bacteriano , Sequenciamento Completo do Genoma , Bacillus thuringiensis/genética , Animais , Proteínas de Bactérias/genética , Toxinas de Bacillus thuringiensis/genética , Endotoxinas/genética , Controle Biológico de Vetores , Tephritidae/genética , Tephritidae/microbiologia , Proteínas Hemolisinas/genética , Larva/genética , FilogeniaRESUMO
Bacillus thuringiensis Berliner is recognized as a predominant bioinsecticide but its antifungal potential has been relatively underexplored. A novel B. thuringiensis strain NBAIR BtAr was isolated and morphologically characterized using light and scanning electron microscopy, revealing presence of bipyramidal, cuboidal, and spherical parasporal crystals. The crude form of lipopeptides was extracted from NBAIR BtAr and assessed for its antagonistic activity in vitro, and demonstrated 100% inhibition of Sclerotium rolfsii Sacc. at a minimum inhibitory concentration of 50 µL of the crude lipopeptide extract per mL of potato dextrose agar. To identify the antagonistic genes responsible, we performed whole genome sequencing of NBAIR BtAr, revealing the presence of circular chromosome of 5,379,913 bp and 175,362 bp plasmid with 36.06% guanine-cytosine content and 5814 protein-coding sequences. Average nucleotide identity and whole genome phylogenetic analysis delineated the NBAIR BtAr strain as konkukian serovar. Gene ontology analysis revealed associations of 1474, 1323, and 1833 genes with biological processes, molecular function, and cellular components, respectively. Antibiotics & secondary metabolite analysis shell analysis of the whole genome yielded secondary metabolites biosynthetic gene clusters with 100%, 85%, 40%, and 35% similarity for petrobactin, bacillibactin, fengycin, and paenilamicin, respectively. Also, novel biosynthetic gene clusters, along with antimicrobial genes, including zwittermicin A, chitinase, and phenazines, were identified. Moreover, the presence of eight bacteriophage sequences, 18 genomic islands, insertion sequences, and one CRISPR region indicated prior occurrences of genetic exchange and thus improved competitive fitness of the strain. Overall, the whole genome sequence of NBAIR BtAr is presented, with its taxonomic classification and critical genetic attributes that contribute to its strong antagonistic activity against S. rolfsii.
RESUMO
BACKGROUND: Virtual Reality (VR) based diagnostic and therapeutic interventions have opened up new possibilities for addressing the challenges in identifying and treating individuals with Autism Spectrum Disorders (ASD). AIM: To conduct a systematic review and meta-analysis of Randomized Controlled Trials to investigate the impact of Immersive VR techniques on the cognitive, social, and emotional skills of under-18 children and adolescents with ASD. METHODS AND PROCEDURES: Four databases were systematically searched as per "Preferred Reporting Items for Systematic Reviews and Meta-analyses" guidelines and assessed six RCTs for further analysis. The Cochrane Risk of Bias tool was used to assess the methodological quality of the studies. OUTCOMES: Pooled results favoured VR and reported significant differences between experimental and control groups concerning social skills (SMD:1.43; 95 % CI: 0.01-2.84; P: 0.05), emotional skills (SMD: 2.45; 95 % CI: 0.21-4.18; P: 0.03) and cognitive skills. CONCLUSION: VR offers an array of benefits that make it a promising tool for children and adolescents with ASD to improve their cognitive, social and emotional skills in a safe and supportive setting. However, accessibility, affordability, customization, and cost are also significant aspects to consider when developing and implementing VR-based interventions for ASD.