Biodegradable plant pots made from dried banana pseudo‐stems enriched with a Bacillus sp.‐biochar composite as an eco‐friendly alternative to plastic pots

Kebun Raya Liwa’s soil has the potential to allow for a population of microorganisms such as the Bacillus sp. Bacillus sp. Kebun Raya Liwa are known to produce phytohormones that have the potential to help plant growth and development, one of which is the hormone Indole Acetic Acid (IAA). This study aims to determine the potential of Bacillus sp. from the soil of Kebun Rawa Liwa in producing IAA hormones. The research method included taking soil samples, preparing Nutrient Agar (NA) medium, measuring soil pH samples, isolating soil bacteria, purifying and characterizing Bacillus sp., preparing IAA standard curves, and testing the potency of Bacillus sp. IAA production was carried out in two ways, namely measuring the content of IAA with the addition of tryptophan and without the addition of tryptophan. IAA concentration was measured using a spectrophotometer with a wavelength of 520 nm. The data obtained is presented in tabular form. The isolation results obtained 10 isolates that were able to produce IAA hormone with and without tryptophan. The highest IAA production without tryptophan was isolate BP 5 with a concentration of 1.18 ppm, and the isolate that was able to produce the highest IAA with tryptophan was isolate BP 13 with a concentration of 3.90 ppm. This indicates that the isolate Bacillus sp. from the soil rhizosphere Kebun Raya Liwa can produce IAA hormones.

Root rot caused by the pathogen Fusarium oxysporum is the number one cause of pea plant (P. sativum L.) death. There are many potential advantages to using rhizobacteria, endophytic bacteria and phyllospheric bacteria for managing plant diseases and promoting plant growth. This study investigated the potentiality of consortium species of bacteria to suppress root rot disease and their ability to promote the growth of pea plants compared with their individual and control plants. A total of 55 phyllospheric bacteria were isolated from mango flower and Bacillus sp. LBF- 02, Bacillus sp. LBF- 03 and Bacillus sp. LBF- 05 showed the most potent antimicrobial activity against root rot pathogens in a dual culture assay. Identification of phyllobacterial strain LBF- 01, LBF- 03 and LBF-05 were done by 16S rDNA sequence analysis using 704f forward primer (50-AGATTTTCCGACGGCAGGTT-30) and 907r reverse primer (50-CCGTCAATTCMTTTRAGTTT-30) with the PCR conditions. Their ability to solubilize phosphate, produce ammonia, siderophore and indole acetic acid, as well as produce extracellular enzymes in vitro was excellent. The results of a greenhouse study found that pea seed treated with consortium isolate significantly increased high germination rates and vigour indexes, as well as shoot and root length, fresh and dry weights, as compared with seed treated with single isolate and control. The defense enzyme activities in consortium treated pots were higher than those in individual and control pots. The plants treated with consortium exhibited higher levels of chlorophyll and carotenoids content in their leaves compared to the untreated control and single treated plants. A significant variation in the chemical profile of pea plants was found (F7,16 ? 2.598; P ? 0.048) resulting from different treatments (T1-T8). After evaluating a variety of growth and microbiological parameters, it was concluded that inoculation with the microbial consortium contributed to raising healthy and vigorously growing pea seedlings in greenhouse conditions, which is applicable in the field in future for sustainable farming.

Exploring indoleacetic acid (IAA) biosynthesis pathways of plant growth promoting bacteria and their ability to synthesize IAA is crucial for understanding the promotion mechanism and for developing more efficient microbial fertilizer. In this study, 118 bacterial endophytic strains were isolated from tomato root and 68 isolates were identified as members of Bacillus and Pseudomonas genus. After screening abilities to synthesize IAA in vitro and promote plant growth for these identified Bacillus and Pseudomonas strains, 7 endophytic strains Bacillus sp. Y_21, B. paramycoides Y_29, B. albus Y_96, B. cereus Y_121, P. plecoglossicida Y_157, Bacillus sp. Y_165 and B. aryabhattai Y_170 strains showed a significant promotion role on wheat root or leaf, including 4 endophytic strains with the potential ability to utilize intermediate metabolites, such as tryptamine and indole acetamide, to produce IAA. Genomic sequencing analysis for selected representative plant growth promoting endophytes showed that IAA-producing bacteria B. cereus mr31 and P. putida Y_166 separately harbored a complete indoleacetamide (IAM) and complete tryptamine (TAM) pathway; whereas, Bacillus sp. Y_165 and B. aryabhattai Y_170, two strains producing IAA not using tryptophan but with indole-3-acetamide, had an incomplete IAM pathway. Fermentation experiments of three genome-sequenced strains using wheat or tomato root extracts as substrate, and combining with UHPLC–MS/MS analysis for wheat root extracts, demonstrated that Bacillus sp. Y_165 strain might produce IAA by using the plant-derived indole-3-acetamide. Our study first demonstrated a novel potential mechanism for the plant growth promoting endophytes to biosynthesize IAA using plant-derived intermediates. This additional mechanism has deepened our understanding of how bacterial endophytes promote plant health and resilience, offering valuable insights about how plants regulate IAA homeostasis within their internal tissues in association with bacterial endophytes.Graphical

It is now a well-known fact that indole acetic and indole butyric acids, when applied in lanolin to cut apices of stems suppress the formation of lateral buds, as do the terminal buds themselves. Thimann and Skoog (9) were the first to demonstrate this when they applied an extract from Rhizopus suinus to decapitated Vicia faba seedlings and found that the lateral buds were inhibited. It was later found that the active substance was indole acetic acid. Since that time other investigators have demonstrated the same thing for other plants (2, 3, 6, 7, 8, 9,10). In some laboratory experiments with Helianthus annuus the writer applied indole acetic acid and phenylacetic acids in lanolin to the cut surfaces of stems. After some time it was noticed that some of the treated plants had produced lateral buds while others had not and when a check was made it was found that the treated plants that produced shoots were the ones that had been treated with phenylacetic acid. This interesting observation led to a more detailed and carefully controlled experiment. Helianthus annuus was used again because under normal treatment it never produces any lateral buds or branches. Four lots of 16 plants each were carefully selected, besides some control plants not decapitated. These plants were between 60 and 70 centimeters tall; no flower buds had as yet been formed. Ten to 15 cm. of the top were cut off from each one of these 64 plants. The cut was always about one centimeter above a node. One per cent, indole acetic, indole butyric, and phenylacetic acids mixed separately in lanolin, as well as lanolin alone, were used. Sixteen plants were treated with each chemical on March 20, 1939. A considerable amount of material was smeared on the freshly cut surface, but it was not repeated during the time of the experiment. On April 10 representative plants from each group were photographed (fig. 1). At that time the plants treated with the auxin showed the typical gall formation, but no buds or lateral shoots had been formed on any of the plants treated with indole acetic and butyric acids. The plants treated with phenylacetic acid had on the other hand formed as many and nearly as large buds as the plants treated with plain lanolin. A month later (May 13) representative plants from each lot were again photographed (fig. 2). As the photograph shows, all of the plants except those not decapitated had by now produced some buds or branches. It is to be remembered that during a period of 54 days no new auxin application had been made. By

Biochar to the rescue: Balancing the fire performance and mechanical properties of polypropylene composites

We explored the membrane lipid and fatty acid composition and plant growth–promoting (PGP) mechanisms of two bacterial endophytes, Bacillus sp. E25 and Bacillus sp. CR71, under saline stress, that is known to be a major detriment to crop yield. Effect of single and co-inoculation of the strains on root and shoot lengths, relative chlorophyll content, and plant biomass in tomato plants (Lycopersicon esculentum cv Saladette) grown in greenhouses was also evaluated. Our results show that single and co-inoculated tomato plants with bacilli strains E25 and CR71, growing under normal or saline stress conditions (100 and 200 mM NaCl), exhibited an increase in root and shoot lengths, chlorophyll content, and biomass parameters, compared with control plants (uninoculated). Additionally, these bacilli strains were antagonistic toward fungal pathogens Fusarium oxysporum and (to a greater extent) Botrytis cinerea in the presence or absence of NaCl. Interestingly, both endophytes maintained good PGP activities, producing compounds like indole-3-acetic acid (IAA), proteases, siderophores, and biofilm. Saline conditions led to changes in membrane phospholipid and fatty acid levels in both. Phosphatidylethanolamine biosynthesis and branched (16:1∆9; 17:0i) and unsaturated fatty acids increased in E25; CR71 showed increase in relative amounts of the same fatty acids and accumulated an unidentified lipid. Bacillus strains E25 and CR71 differentially modify their membrane phospholipid composition as a protective mechanism, potentially for maintaining PGP activities, under saline stress.

Arsenic (As) pollution in both soil and water is a global threat and challenge to us. Soil As contamination resulted in desolation of agricultural land and damaging human health via the food chain. Plant growth promoting bacteria (PGPB) enhance the ability of heavy metal/metalloid tolerance, increase biomass production in plant under adverse condition and also reduce the soil toxicity. This present study focuses on selection of the plant growth promoting trait within arsenite resistant bacteria, previously isolated from As contaminated soils of Faridpur district, Bangladesh. A total of 17 arsenite resistant bacteria belonging to 8 different genotypes comprising 6 different genera (Bacillus, Pseudomonas, Delftia, Wohlfahrtiimonas, Dietzia and Brevibacillus) were screened for their ability to produce plant growth promoting abilities such as indole acetic acid (IAA) production and phosphate solubilization (PS). Among 17 isolates, 15 93.75% (15/16) isolates produced IAA and 83.71% (12/14) isolates had the capacity to solubilize phosphate. Arsenite resistant Bacillus spp. were highly potent in both IAA production (33.33%) and phosphate solubilization (50%) followed by Pseudomonas spp. (40% IAA and 33.33% PS). High IAA production (91.5?g/ml) was exhibited by isolate Bacillus sp. A1b possessing a MICarsenite of 10 mM and maximum phosphate solubilization was observed by Bacillus sp. H2k. One of the arsenite resistant bacteria Detzia sp. H2f having 27 mM arsenite tolerance were able to produce IAA and showed maximum PS ability that was not previously reported. These isolates can be potential candidates for the enhancement of plant growth, provide protection of plants against As toxicity and be beneficial for sustainable agronomic production in As contaminated soils.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 25-31

Indole Acetic Acid (IAA) is the important phytohormone for boosting plant-growth promotion. It is related with amino acid tryptophan as a precursor for building IAA. However some bacteria such as Bacillus sp. and Escherichia coli enable to produce IAA without L-tryptophan on culture medium via the tryptophan independent pathways. This study aims to determine the potential of indigenous Bacillus sp. and E. coli isolate in producing IAA via Trp-independent pathways (without L- tryptophan). The stage of this study consists of growing of isolate on liquid media without tryptophan and measuring the levels of IAA using Salkowsky method. Bacillus sp and Escherichia coli could produce IAA with the concentration of 0,0236 mmol/L and 0,024 mmol/L, respectively. The concentration of IAA produced by these bacteria is quite low because of their ability to synthesis IAA from the independent tryptophan pathway. The independent tryptophan pathway means these bacteria could synthesize IAA without using tryptophan as a precursor on their growth medium.

The effect of a plant growth-promoting bacterium (PGPB) Bacillus sp. V2026, a producer of indolyl-3-acetic acid (IAA) and gibberellic acid (GA), on the ontogenesis and productivity of four genotypes of early-maturing spring wheat was studied under controlled conditions. The inoculation of wheat plants with Bacillus sp. V2026 increased the levels of endogenous IAA and GA in wheat of all genotypes and the level of trans-Zeatin in Sonora 64 and Leningradskaya rannyaya cvs but decreased it in AFI177 and AFI91 ultra-early lines. Interactions between the factors “genotype” and “inoculation” were significant for IAA, GA, and trans-Zeatin concentrations in wheat shoots and roots. The inoculation increased the levels of chlorophylls and carotenoids and reduced lipid peroxidation in leaves of all genotypes. The inoculation resulted in a significant increase in grain yield (by 33–62%), a reduction in the time for passing the stages of ontogenesis (by 2–3 days), and an increase in the content of macro- and microelements and protein in the grain. Early-maturing wheat genotypes showed a different response to inoculation with the bacterium Bacillus sp. V2026. Cv. Leningradskaya rannyaya was most responsive to inoculation with Bacillus sp. V2026.

Drought stress affects not only crop growth but also its morpho-physiological and biochemical traits to reduce crop productivity. The study reported in this article was designed and implemented to determine the effects of deficit irrigation and bacterial inoculation on flax plants. For this purpose, seeds were inoculated with Bacillus amyloliquefaciens (B1 ), Bacillus sp. Strain1 (B2 ), and Azotobacter chroococcum (A) as plant growth promoting rhizobacteria (PGPR). The individual inoculated plants were then grown under field conditions in 2015, while individually and in combination in pots in 2016. The irrigation regimes in either experiments included 50, 75 and 100% crop water requirement. Bacterial cultures were observed to produce ammonia (except B2 ), indole acetic acid and siderophores. Results showed that the PGPRs significantly mitigated the effects of water deficit. Compared with the control plants, the bacterially-inoculated plants had an enhanced relative water content, plant height, water-soluble carbohydrate and proline contents and antioxidant enzyme activities, but a decreased malondialdehyde content. B1 exhibited greater effects on most of the traits investigated under the field conditions rather than those with moderate and severe drought stress, while application of the triple bacteria in pots had greater effects on relative water content, carbohydrate and proline contents as well as malondialdehyde. The significant differences in abiotic stress indicators in PGPR-treated plants suggest that these bacteria could be used as biofertilizers to assist plant growth and to reduce the adverse effects of deficit irrigation.

A natural bacterial isolate that shows multiple plant growth-promoting activities was isolated from fermented panchagavya (a mixture of five indigenous cow products). It is a gram-positive, endospore-forming bacteria identified as Bacillus sp. PG-8 by 16S rRNA gene sequencing. The Bacillus sp. PG-8 have shown multiple plant growth-promoting activities as indole acetic acid (2.78 μg/ml), gibberellic acid (0.7 mg/ml), ammonia (6.51 μmol/ml), exopolysaccharide (2.6% w/v) production, and phosphate solubilization (198.27 μg/ml). The Bacillus sp. PG-8 has ability to survive under the abiotic stress conditions such as temperature (28–46°C), pH (5.0–12.0), salt (0.5–20.0% w/v NaCl), and osmotic resistance (1–10% w/v PEG-6000). Due to its diverse characteristics, the effect of Bacillus sp. PG-8 was tested on Arachis hypogea (groundnut). The seeds treated with Bacillus sp. PG-8 demonstrated a 70% germination rate with seedling vigor indexes of 154. In pot study, Arachis hypogea growth showed 1.38, 1.38, 1.32, 1.39, and 1.52 times increase in root hair number, leaf numbers, leaf width, leaf length, and leaf area, respectively. The addition of Bacillus sp. PG-8 culture to the Arachis hypogea plant resulted in a significant improvement in plant growth. Bacillus sp. PG-8 is a spore producer with stress tolerance and multiple plant growth-promoting properties, which makes it a potential liquid biofertilizer candidate.

This study was undertaken to investigate the nature of hormonal changes in relation to drought stress in two cultivars of Sorghum bicolor L. Moench. Two cultivars, M–35 and NK300, were grown in a field plot protected by a rain shelter. Plants in one soil compartment were stressed by withholding water while those in another (controls) were irrigated frequently. Levels of the plant hormones abscisic acid (ABA), phaseic acid (PA) and indole-3-acetic acid (IAA) measured by high-performance liquid chromatography (HPLC) were determined in the youngest leaves of control and stressed plants at intervals throughout the growth cycle. Plant height, senescence, and leaf water status were also determined. Leaf water potential (ψw) and solute potential (ψs) were reduced in both cultivars by drought stress; values for M–35 plants were lower than NK300. Leaf senescence was higher in M–35 plants and was promoted by stress in both cultivars. Cultivar M–35 behaved as a drought-tolerant plant whereas cultivar NK300 behaved more like a drought avoider. ABA levels were higher in M–35 control plants than in corresponding NK300 plants and levels in both cultivars followed seasonal changes in leaf water potential. Under drought stress, ABA levels increased between 1.5 and 2 times in both cultivars with the largest increases occurring during the vegetative stage in M–35 and during the flowering stage for NK300. PA levels in both cultivars were higher in stressed than in control plants. PA levels in M–35 plants were relatively low and constant throughout the life cycle, whereas in NK300, levels were high until shortly before flowering. IAA levels were higher in NK300 than in M–35 plants, particularly during the vegetative stage. Under drought stress, IAA levels were reduced in both cultivars with a more pronounced reduction in NK300. The high level of ABA in the more drought-tolerant cultivar M–35 was associated with low leaf ψw and ψs and high leaf senescence. On the other hand, in the drought avoider, NK300, high levels of IAA and PA were associated with high leaf ψw and ψs. It is concluded that these cultivars, which differ in their response to drought stress, can be distinguished by their leaf hormone levels.

This study was carried out in order to develop a biological control of anthracnose of red pepper caused by fungal pathogens. In particular, this study focuses on the Colletotrichum species, which includes important fungal pathogens causing a great deal of damage to red pepper. Antagonistic bacteria were isolated from the soil of pepper fields, which were then tested for biocontrol activity against the Colletotrichum gloeosporioides anthracnose pathogen of pepper. Based on the 16S rRNA sequence analysis, the isolated bacterial strain CS-52 was identical to Bacillus sp. The culture broth of Bacillus sp. CS-52 had antifungal activity toward the hyphae and spores of C. gloeosporioides. Moreover, the substances with antifungal activity were optimized when Bacillus sp. CS-52 was grown aerobically in a medium composed of 0.5% glucose, 0.7% K2HPO4, 0.2% KH2PO4, 0.3% NH4NO3, 0.01% MnSO4·7H2O, and 0.15% yeast extract at 30℃. The inhibition of spore formation resulting from cellulase, siderophores, and indole-3-acetic acid (IAA), were produced at 24 h, 48 h, and 72 h, respectively. Bacillus sp. CS-52 also exhibited its potent fungicidal activity against anthracnose in an in vivo test, at a level of 70% when compared to chemical fungicides. These results identified substances with antifungal activity produced by Bacillus sp. CS-52 for the biological control of major plant pathogens in red pepper. Further studies will investigate the synergistic effect promoting better growth and antifungal activity by the formulation of substances with antifungal activity.

Endophytic Bacillus sp. AP10 harboured in Arabis paniculata mediates plant growth promotion and manganese detoxification

Evaluation of electrospinning parameters on the tensile strength and suture retention strength of polycaprolactone nanofibrous scaffolds through surface response methodology