Piper caninum extract and Brevibacillus agri mixture suppresses rice leaf spot pathogen; Nigrospora oryzae and improves the production of red rice (Oryza sativa L)

Under the guise of enhancing productivity, using pesticides and artificial fertilizers in agriculture affects both the environment and living things. High chemical residues in food and the environment disrupt the health of consumers. One of the solutions that can bring about a reduction in the use of pesticides and chemicals is switching to organic fertilizers. The application of biopesticides originating from biological sources such as plant extracts and the use of microbes is gaining global acceptance. Therefore, this study aimed to obtain the best biopesticides and biostimulants that could suppress the leaf spot pathogen, Nigrospora oryzae, and increase the growth and yield of Bali red rice. The study contained four treatments, namely untreated control (F0), Piper caninum leaf extract (F1), Brevibacillus agri (F2), and fermented P. caninum leaf extract plus B. agri (F3). The treatments were arranged in a randomized complete block design, and each treatment was replicated three times. The parameters measured were the number of tillers per plant, number of leafs per plant, chlorophyll content, number of grains per panicle, grain weight, and grain yield. Furthermore, antimicrobial and antioxidants were assayed using SEM. GC-MS. At the end of the experiment, the disease index of the leaf spot was measured. The results showed that F3 significantly suppressed leaf spots caused by N. oryzae compared to other treatments, including untreated control in red rice. Additionally, the F3 significantly increased the number of productive tillers, number of grains per panicle, and grain yield compared to all other treatments. The F3 enhanced the crop yield at 6.19 tons/ha, an increase of 50% compared to the untreated control. The SEM.GC-MS results showed the presence of 2.3 butanediol, tetra-decanoic acid, butanoic acid, ethyl ester, benzene propanal, 3-(1,1-dimethylethyl)-a-methyl, a-N-Normethadol in treated plants with P. canicum plus B. agri.

Rhizobacteria of Bali With Obvious Growth-Promoting Properties on Corn (Zea mays L.)

Corn productivity in Indonesia is still relatively low compared with other countries. Therefore, it is necessary to increase the productivity of corn by using rhizobacteria, which have multiple traits. This study was conducted to obtain indigenous rhizobacteria of Bali that have multiple traits, can produce indoleacetic acid (IAA), fix nitrogen from atmosphere, produce siderophores, colonize roots, increase seed germination, and promote the growth of corn. Isolation of rhizobacteria was carried out from the rhizosphere of plants belonging to the Gramineae family that grows in Bali Island, Indonesia. Six isolates, namely, Sr3, Tb9, Rg1, Rg23, Al27, and Jg8, could produce IAA, fix nitrogen from the atmosphere, produce siderophores, and increased germination rate and vigor index of corn seedling. Among them, three isolates, namely, Rg1, Sr3, and Jg8, significantly (p <0.05) increased the germination rate of corn seeds, increased vigor index, increased root dry weight and shoot dry weight of corn at the age of 7 days, and were able to colonize corn roots. Compared with the control, the rhizobacteria treatment increased the germination of corn seeds ranging from 5.04 to 13.05%. Based on the analysis of the 16S rRNA gene, it was found that these rhizobacteria species were Glutamicibacter nicotianae strain Rg1 (accession number OM349119), Brevibacillus invocatus strain Sr3 (accession number OM327515), and Micrococcus luteus strain Jg8 (accession number OM362349). Under a greenhouse condition, all the three isolates significantly (p <0.05) increased nutrient uptake, the leaf chlorophyll content, net assimilation rate, and crop growth rate of corn when compared with control. These results suggested that these isolates of rhizobacteria obviously promoted the growth of corn and can be developed as biostimulant to promote the growth and increase the corn yield in Bali, Indonesia.

Inhibitory effects of Moringa oleifera leaves extract on xanthine oxidase activity from bovine milk

Moringa oleifera is a tropical plant in the Moringaceae family that contains a lot of bioactive compounds. This study aimed to isolate and characterize the enzyme xanthine oxidase (XO), and conducted inhibitory tests on XO using methanol extracts of M. oleifera leaves. The xanthine oxidase enzyme isolated from bovine milk was characterized to determine the optimum pH, temperature, and substrate concentration. XO inhibition was evaluated by in vitro and in silico methods. The results of XO isolation and characterization of bovine milk showed the optimum conditions at pH 6.5, substrate concentration of 0.1 mM, and temperature 35 °C with an activity rate of 32.47 mU/mL; 21.55 mU/mL, and 21.94 mU/mL. Inhibition analysis results on methanol extract of M. oleifera leaves showed the highest activity decrease at the extract concentration of 160 ppm, with a relative inhibition value of 21.35%, while allopurinol as a positive control has a relative value inhibition of 61.21%. Relative value inhibition indicated the potential of M. oleifera leaves as a source of medicinal plants for gout sufferers. Additionally, a computational analysis was performed to observe the molecular interaction between the primary compounds of M. oleifera leaves, i.e., 5-O-acetyl-thio-octyl-β-L-rhamnofuranoside, quinic acid, and 2-dimethyl(trimethylsilylmethyl)silyloxymethyltetrahydrofuran, and XO using the molecular docking method. The finding implied that these compounds are bound to the catalytic sites of XO by hydrogen bonds and hydrophobic interactions, indicating the primary compounds of M. oleifera leaves could become XO inhibitors to treat gout disease.

Microbial contamination of diesel-biodiesel blends in storage tank; an analysis of colony morphology

Fuel contamination is a major issue that comes with the utilization of biodiesel. Microbial growth is one of the primary causes of contamination during fuel handling and storage. This work attempts to identify the types, shapes, and growth profiles of microorganisms on fuel samples. The morphology of microbial colonies is presented in order to analyze the potential of fuel contamination. The diesel, biodiesel, and blends are stored in stainless steel (SS) and glass tanks, where each is placed indoors and outdoors during the 90 days of storage time. The morphology of microbial colonies is observed through a microscope with a magnification of 1000× and the quantity is calculated by a digital colony counter. Microbial contamination in all samples is considered as high contamination where the Colony Forming Unit (CFU) is greater than 10⁵ L⁻¹. Colony forms are far more assorted in blends than in pure diesel (B0) and neat biodiesel (B100). The transformation of microbial colonies accelerates after 60 days of storage time. The results reveal that the number of bacterial colonies that grow in B20 is higher and more varied, nevertheless, the contamination in B100 is significantly higher. This is indicated by a 1.5-fold rise in B20 acidity and a 2.5-fold increase in water content compared to the initial condition.

Production of Plant Beneficial and Antioxidants Metabolites by Klebsiellavariicola under Salinity Stress

Bacteria that surround plant roots and exert beneficial effects on plant growth are known as plant growth-promoting rhizobacteria (PGPR). In addition to the plant growth-promotion, PGPR also imparts resistance against salinity and oxidative stress and needs to be studied. Such PGPR can function as dynamic bioinoculants under salinity conditions. The present study reports the isolation of phytase positive multifarious Klebsiella variicola SURYA6 isolated from wheat rhizosphere in Kolhapur, India. The isolate produced various plant growth-promoting (PGP), salinity ameliorating, and antioxidant traits. It produced organic acid, yielded a higher phosphorous solubilization index (9.3), maximum phytase activity (376.67 ± 2.77 U/mL), and copious amounts of siderophore (79.0%). The isolate also produced salt ameliorating traits such as indole acetic acid (78.45 ± 1.9 µg/mL), 1 aminocyclopropane-1-carboxylate deaminase (0.991 M/mg/h), and exopolysaccharides (32.2 ± 1.2 g/L). In addition to these, the isolate also produced higher activities of antioxidant enzymes like superoxide dismutase (13.86 IU/mg protein), catalase (0.053 IU/mg protein), and glutathione oxidase (22.12 µg/mg protein) at various salt levels. The isolate exhibited optimum growth and maximum secretion of these metabolites during the log-phase growth. It exhibited sensitivity to a wide range of antibiotics and did not produce hemolysis on blood agar, indicative of its non-pathogenic nature. The potential of K. variicola to produce copious amounts of various PGP, salt ameliorating, and antioxidant metabolites make it a potential bioinoculant for salinity stress management.

Recent Understanding of Soil Acidobacteria and Their Ecological Significance: A Critical Review

Acidobacteria represents an underrepresented soil bacterial phylum whose members are pervasive and copiously distributed across nearly all ecosystems. Acidobacterial sequences are abundant in soils and represent a significant fraction of soil microbial community. Being recalcitrant and difficult-to-cultivate under laboratory conditions, holistic, polyphasic approaches are required to study these refractive bacteria extensively. Acidobacteria possesses an inventory of genes involved in diverse metabolic pathways, as evidenced by their pan-genomic profiles. Because of their preponderance and ubiquity in the soil, speculations have been made regarding their dynamic roles in vital ecological processes viz., regulation of biogeochemical cycles, decomposition of biopolymers, exopolysaccharide secretion, and plant growth promotion. These bacteria are expected to have genes that might help in survival and competitive colonization in the rhizosphere, leading to the establishment of beneficial relationships with plants. Exploration of these genetic attributes and more in-depth insights into the belowground mechanics and dynamics would lead to a better understanding of the functions and ecological significance of this enigmatic phylum in the soil-plant environment. This review is an effort to provide a recent update into the diversity of genes in Acidobacteria useful for characterization, understanding ecological roles, and future biotechnological perspectives.

Adaptation of broccoli (Brassica oleracea var. italica L.) to high and low altitudes in Bali, Indonesia

Abstract. Astarini IA, Defiani MR, Suriani NL, Griffiths PD, Stefanova K, Siddique KHM. 2020. Adaptation of broccoli (Brassica oleracea var. italica L.) to high and low altitudes in Bali, Indonesia. Biodiversitas 21: 5263-5269. Broccoli is an important vegetable worldwide, with expanding markets and opportunities in Asia. In Indonesia, there is demand from high-end hotels, restaurants, and export markets, but the local supply is low quality and low yielding. Crown cuts are typically small and misshapen as the varieties are grown are not adapted to local environments. This study targeted new broccoli varieties to identify those best adapted to environmental stresses in Bali, Indonesia, using two-site replicated field experiments. Experiments were undertaken in two regions in Bali (Bedugul and Tabanan) using 13 commercial varieties that included heat-sensitive varieties and others identified as heat-tolerant in trials on the East Coast of the USA. The trials evaluated the varieties for crown initiation, days to maturity, crown size at harvest, crown diameter, and overall performance. The study demonstrated that all 13 varieties could be used for broccoli production in the Bedugul region (1200 m a.s.l. altitude), with Castle Dome being the best performer due to its earlier maturity and large high-quality crown. The varieties Bay Meadows, Belstar, Imperial, and Sarasota could be used in the Tabanan region.