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Use of Plant-Associated Bacillus Strains as Biofertilizers and Biocontrol Agents in Agriculture
Abstract and Figures
Plant-growth-promoting rhizobacteria (PGPRs) offer an environment-friendly and efficient alternative to chemical pesticides and fertilizers. Among them, endospore-forming bacilli are especially attractive because their long-term stability is comparable with that of agrochemicals. Although their use is steadily increasing, exploiting of these biologicals is still limited by insufficient knowledge about the mechanisms underlying plant growth promotion and biological control. However, in recent years, some progress was made in uncovering molecular mechanisms responsible for beneficial interactions between PGP bacilli and plants. We describe here some aspects of the plant–PGP bacilli relationship in light of the genomic data recently obtained from Bacillus amyloliquefaciens, and propose to choose B. amyloliquefaciens FZB42 as a paradigm for further research on PGP bacilli.
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... The deployment of biocontrol micro-organisms has been attempted to control plant diseases and promote plant growth [3]. Bacillus, Pseudomonas, and Trichoderma species are the main biocontrol microbial resources [4,5]. ...
... During colonization, PGPR strains produce a wide spectrum of bioactive metabolites such as antibiotics, siderophores, volatile organic compounds (VOCs), and quorum-sensing signals to compete with other micro-organisms and survive in the rhizosphere [9,10]. Among these PGPR strains, the Bacillus species has received extensive attention and has become an important potential resource for biofertilizers or biopesticides, which are frequently used to control soil-borne plant diseases in the field and greenhouse [4,7]. ...
... Bacillus species have been developed as biofertilizers and biopesticides due to their ability to control soil-borne diseases and promote plant growth [4]. The biocontrol activities include several mechanisms, such as antagonism, competition, and plant resistance induction [6,27]. ...
The plant-growth-promoting rhizobacteria (PGPR) B. subtilis PTS-394 has been utilized as a biocontrol agent (in a wettable powder form) due to its excellent ability to suppress tomato soil-borne diseases caused by Fusarium oxysporum and Ralstonia solanacearum. In this study, we evaluated the biocontrol efficiency of Bacillus subtilis PTS-394 wettable powder on pepper root rot in pot experiments and field trials. B. subtilis PTS-394 and its lipopeptide crude extract possessed excellent inhibition activity against Fusarium solani, causing pepper root rot; in an antifungal activity test B. subtilis PTS-394 wettable powder exhibited a good ability to promote pepper seed germination and plant height. The experiments in pots and the field indicated that B. subtilis PTS-394 wettable powder had an excellent control effect at 100-fold dilution, and its biocontrol efficacy reached 69.63% and 74.43%, respectively. In this study, the biocontrol properties of B. subtilis PTS-394 wettable powder on pepper root rot were evaluated and its application method was established. It was concluded that B. subtilis PTS-394 wettable powder is a potential biocontrol agent with an excellent efficiency against pepper root rot.
... Most of them are species that are safe for humans, animals and plants. Due to the above-mentioned characteristics of the bacteria Bacillus sp., they are used for the production of commercial preparations in the form of insecticides or biostimulants and are involved in supporting plant production [17][18][19][20]. Bacillus sp. ...
... subtilis, B. cereus, B. thuringiensis, B. pumilus, B. megaterium, etc.) have evolved mechanisms to stimulate plant growth by increasing the availability of the nutrients: N, P, potassium (K) and iron (Fe). Moreover, Bacillus strains are capable of fixing molecular nitrogen [19,[21][22][23]. ...
The present state of knowledge and biotechnological advances have allowed the potential of microorganisms to be used effectively in crop cultivation. A field study on the use of commercial bacterial preparations in the cultivation of winter wheat (Triticum aestivum L.) was carried out in the years 2017–2019 at the Educational and Experimental Station in Tomaszkowo (53°71′ N, 20°43′ E), Poland. This study analysed the effect of commercial microbial preparations containing Paenibacillus azotofixans, Bacillus megaterium and Bacillus subtilis, applied during the winter wheat growing season, on the grain yield, protein content, leaf greenness index (SPAD), the course of photosynthesis and the N-NO3, N-NH4 and P contents in the soil. The highest grain yield was noted following the application of mineral fertilisation and the three microbial preparations in combination (Paenibacillus azotofixans, Bacillus megaterium and Bacillus subtilis), as well as NPK with Paenibacillus azotofixans, in relation to mineral fertilisation alone (by 19.6% and 18.4%, respectively). The microbial preparations had a significant effect on the leaf greenness index (SPAD) at both test dates. No interaction was recorded between the years of study and the preparations applied on the SPAD values. The highest leaf photosynthetic index at both observation dates was noted for the application of NPK + P. azotofixans, as well as for NPK and all the preparations combined (P. azotofixans, B. megaterium, B. subtilis). The highest N-NO3, N-NH4 and P contents in the soil were obtained using NPK and all microbial preparations combined. Strong correlations were found between the SPAD index and the photosynthetic index value and the protein content in wheat grains and between the N-NO3, N-NH4 and P contents in the soil and the wheat grain yield.
... China Song et al., 2021 significantly. Such bacteria possess unique characteristics which enhance crop yield as well as lessen the usage of agrochemicals including inorganic fertilizers (Borriss, 2011). It has been reported that Rhizobium and Azospirillum demonstrate plant growthpromoting characteristics with the synthesis of plant hormones such as Auxins, Gibberellins, Cytokinins, and Ethylene. ...
A large amount of nitrogen (N) fertilizer is required for paddy cultivation, but nitrogen use efficiency (NUE) in paddy farming is low (20–40%). Much of the unutilized N potentially degrades the quality of soil, water, and air and disintegrates the functions of different ecosystems. It is a great challenge to increase NUE and sustain rice production to meet the food demand of the growing population. This review attempted to find out promising N management practices that might increase NUE while reducing the trade-off between rice production and environmental pollution. We collected and collated information on N management practices and associated barriers. A set of existing soil, crop, and fertilizer management strategies can be suggested for increasing NUE, which, however, might not be capable to halve N waste by 2030 as stated in the “Colombo Declaration” by the United Nations Environment Program. Therefore, more efficient N management tools are yet to be developed through research and extension. Awareness-raising campaign among farmers is a must against their misunderstanding that higher N fertilizer provides higher yields. The findings might help policymakers to formulate suitable policies regarding eco-friendly N management strategies for wetland paddy cultivation and ensure better utilization of costly N fertilizer.
... This crop is nutritionally demanding and requires chemical treatment due to its great susceptibility to a wide variety of pests and diseases (Araujo, 2008). Studies such as those by Reva et al. (2004) and Borriss (2011) have demonstrated that the use of B. subtilis in cotton can promote plant development and prevent the incidence of diseases. Many studies have shown the benefits of using Bacillus spp. to increase such parameters as plant development, nutrient availability into soil and nutritional status. ...
The use of plant growth-promoting bacteria (PGPB) is a promising alternative method to improve plant efficiency in the utilization of chemical fertilizers, enabling a reduction of fertilizer application on crops. This study aimed to evaluate the potential of ten Bacillus strains (eight B. subtilis, one B. velezensis and one B. amyloliquefaciens) to promote growth in cotton plants under greenhouse conditions. The experiment was performed in a completely randomized design with 11 treatments and five replicates under greenhouse conditions. The parameters related to plant growth from treatments that received the bacterial isolates were compared to the control. The parameters analyzed were shoot dry matter, root dry matter, total dry matter, plant height, nitrogen content and phosphorus content in soil and in plants. The highest root dry matter was 1.24 g for the isolate 263. The total dry matter was 4.0 g for the isolate 248 and 3.54 g for the isolate 290. The highest chlorophyll content was 28 µg/cm2 for the isolate 290. The higher N content in shoot dry matter was 28 g of N for the isolate 290, 26 g for the isolate 248 and 25 g for the isolate 320. The improved P efficiency use was 32% for the isolate 248, 28% for the isolate 188 and 27% for the isolate 274. These results strongly confirm that B. subtilis isolates 248, 290 and 263 may represent a good alternative as plant growth-promoting endophytes to cotton crops, as they positively affected several parameters evaluated, such as root and shoot dry matter and phosphorus content in the soil. In addition, the parameters evaluated can strongly and positively affect plant yield. However, some isolates of B. subtilis did not promote plant growth and most likely failed as bioinoculants. This result shows the importance of properly identifying the isolate for bioinoculation to achieve success in promoting plant growth.
... Microbial-based agricultural inputs have a long history of enhancing plant production, starting with the inoculation of leguminous roots in the early twentieth century (Desbrosses and Stougaard 2011). Certain bacterial strains of Bacillus, Pseudomonas, Glomus, and others have been broadly used (Borriss 2011;Sivasakthi et al. 2014). Moreover, Singh et al. (2011b) stated that using beneficial microorganisms in crop cultivation is considered a perfect strategy for improving the efficiency of the used resources and increasing the outcome yield. ...
Foliar diseases, like powdery mildew, septoria leaf blotch (SLB) and stem rust, affect wheat plants causing severe yield losses. Biofertilizers Pseudomonas fluorescens Migula (NRC2041) and Bacillus subtilis Ehrenberg (NRC313) or the arbuscular mycorrhizal fungi Glomus mosseae Tul. & C. Tul. (NRC212A) and G. fasciculatum Tul. & C. Tul. (NRC212B) were used for soil treatment followed by foliar spray with Trichoderma harzianum or P. fluorescens to manage severity of wheat foliar diseases under field conditions for two successive growing seasons. Under field conditions, at all soil drench and foliar application treatments, Sids 14 was the most sensitive cultivar for high disease severity followed by Misr 2 and Giza 168. Also, the obtained results showed that the most effective treatments were soil drench with mycorrhizae followed by foliar spray with either T. harzianum or P. fluorescens . Meanwhile, the fungicide Amistar showed a superior reduction in disease severity compared to other applied treatments. In addition, the increased yield was correlated to the decreased severity of the recorded diseases. The present study suggests using bioagents for reducing the severity of wheat leaf diseases and increasing the grain yield under field conditions.
... The use of PGPRs as biocontrol agents show great promise for rapid adoption to control plant diseases, including P. colocasiae, the causal agent of TLB, as concerns grow about the overuse of agrochemicals in agriculture (Wu et al., 2021;Özdogȃn et al., 2022). Biocontrol activities of rhizobacterial strains of the genus Bacillus and Pseudomonas have been extensively studied against a broad spectrum of plant pathogens (Borriss, 2011;Berger et al., 2015;Dimkic et al., 2022;Ghadamgahi et al., 2022). Currently, research on biocontrol of plant pathogens is being extended to other rhizobacterial genera such as Serratia, as these strains have proven to be effective biocontrol agents against a number of plant diseases (Liu et al., 2010;Purkayastha et al., 2018;Kshetri et al., 2019). ...
Taro leaf blight caused by Phytophthora colocasiae adversely affects the growth and yield of taro. The management of this disease depends heavily on synthetic fungicides. These compounds, however, pose potential hazards to human health and the environment. The present study aimed to investigate an alternative approach for plant growth promotion and disease control by evaluating seven different bacterial strains (viz., Serratia plymuthica , S412; S. plymuthica , S414; S. plymuthica , AS13; S. proteamaculans , S4; S. rubidaea , EV23; S. rubidaea , AV10; Pseudomonas fluorescens , SLU-99) and their different combinations as consortia against P. colocasiae . Antagonistic tests were performed in in vitro plate assays and the effective strains were selected for detached leaf assays and greenhouse trials. Plant growth-promoting and disease prevention traits of selected bacterial strains were also investigated in vitro . Our results indicated that some of these strains used singly (AV10, AS13, S4, and S414) and in combinations (S4+S414, AS13+AV10) reduced the growth of P. colocasiae (30−50%) in vitro and showed disease reduction ability when used singly or in combinations as consortia in greenhouse trials (88.75−99.37%). The disease-suppressing ability of these strains may be related to the production of enzymes such as chitinase, protease, cellulase, and amylase. Furthermore, all strains tested possessed plant growth-promoting traits such as indole-3-acetic acid production, siderophore formation, and phosphate solubilization. Overall, the present study revealed that bacterial strains significantly suppressed P. colocasiae disease development using in vitro , detached leaf, and greenhouse assays. Therefore, these bacterial strains can be used as an alternative strategy to minimize the use of synthetic fungicides and fertilizers to control taro blight and improve sustainable taro production.
... Beneficial bacteria can produce phytohormones and other compounds. (Borriss, 2011), Algae, yeast, and mycorrhizal fungus are only a few examples of biomasses and their extracts that participate in fermentation and create amino acids. A biofertilizer is a substance that contains an active ingredient or organic agent that is free of agrochemicals and is capable of acting directly or indirectly on all or a portion of cultivated plants to increase productivity, without taking into account their hormonal or stimulating value. ...
Book Available online at: https://www.bhumipublishing.com/books/ PREFACE Life Sciences have always been a fundamental area of science. The exponential increase in the quantity of scientific information and the rate, at which new discoveries are made, require very elaborate, interdisciplinary and up-to-date information and their understanding. Enhanced understanding of biological phenomenon incorporated with interdisciplinary approaches has resulted in major breakthrough products for betterment of society. To keep the view in mind we are delighted to publish our book entitled "Frontiers in Life Science Volume VII". This book is the compilation of esteemed articles of acknowledged experts in the fields of basic and applied life science. This book is published in the hopes of sharing the new research and findings in the field of life science subjects. Life science can help us unlock the mysteries of our universe, but beyond that, conquering it can be personally satisfying. We developed this digital book with the goal of helping people achieve that feeling of accomplishment. The articles in the book have been contributed by eminent scientists, academicians. Our special thanks and appreciation goes to experts and research workers whose contributions have enriched this book. We thank our publisher Bhumi Publishing, India for taking pains in bringing out the book. Finally, we will always remain a debtor to all our well-wishers for their blessings, without which this book would not have come into existence. Editors CONTENT
... The potential of root endophytic fungus and plant growth promoting rhizobacteria can be explored for the purpose of developing a bio-fertilizer for increasing nutrient uptake which in term results in better crop growth and yield. There are several studies conducted on the utilization of PGPR and root endophytic fungus, alone (Borriss 2011;Bagde et al. 2011;Dixit et al. 2020;Ahmad et al. 2020), but only a few targets their combined use especially of Enterobacter sp., Bacillus sp., and P. indica. Therefore, the present study focuses to exploit the potential of bacterial strains, specifically Enterobacter sp. ...
Purpose
Application of beneficial microbes such as plant growth promoting rhizobacteria (PGPR) and endophytic fungi as bio-fertilizer may act as a substitute to minimize the utilization of chemical fertilizers, which often cause negative impacts on environment. In this regard, bio-fertilizer resurged as an alternate and eco-friendly technique for sustainable agriculture to improve crop growth and yield by the introduction of beneficial microorganisms in soil. Therefore, this experiment was designed to investigate whether the following microbial candidates, i.e., Enterobacter sp., Bacillus sp., and Piriformospora indica have the ability to influence growth of canola through uptake of nutrient and production of growth hormone.
Materials and methods
A pot experiment with three beneficial microorganisms such as Enterobacter sp., Bacillus sp., and a root endophytic fungus, P. indica, was conducted on two cultivars of canola (DGL and Punjab canola). The bacterial strain of Enterobacter sp. MN17 and Bacillus sp. MN54 (10⁸ bacteria per seed) were applied individually as well as along with fungal strain (P. indica), and their impact was assessed against an uninoculated control treatment under normal soil condition.
Results and discussion
Results depicted that application of Enterobacter sp. MN17 and Bacillus sp. MN54 with P. indica significantly increased growth, physiological attributes, nutrient uptake, and soil microbiological attributes of canola. In particular, treatment MN54 + P. indica showed highest improvement in shoot biomass, stem diameter, and root length 100%, 65%, and 50% respectively in var. DGL, while increase in number of pods per plant was also recorded for treatment MN17 + P. indica and MN54 + P. indica for DGL (63%) and Punjab Canola (73%), respectively, as compared to control plants. The combined inoculation also increased root or/and shoot nutrient uptake and enhanced plant auxin pool. Therefore, colonization of P. indica and microbial strain, especially Bacillus sp., improves plant health by enhancing root proliferation because of upregulation of auxin producing genes and release of organic acids, respectively, which leads to better nutrient uptake and eventually enhanced crop growth.
Conclusion
Our results proposed that inoculation of Bacillus sp. MN54 with P. indica could be exploited to increase crop growth and seed yield through enhanced nutrient uptake and production of plant growth hormones.
Microbes are an integral component of the soil ecosystem but degraded soil has few native beneficial microbes. This necessitates the characterization of phytobeneficial bacteria having numerous features. The study was initiated to evaluate rhizobacteria enhancing Acacia (Acacia abyssinica) seed germination. Isolates were selected based primarily on phosphate solubilization activity and other traits hydrogen cyanide (hcn), phytohormone, hydrolytic enzyme, siderophore, ammonia. Among isolates, 45% each was categorized as high and medium phosphate solubilizers and the amount was found to range from 195 to 373 µg/mL. The highest solubilization index (SI) 7 was recorded for Acinetobacter BS-27 and 6 for Pantoea BS-38. The maximum P and iaa were produced by Pseudomonas FB-49 (373 and 659.07µg/mL), respectively. Isolates with multiple traits were chosen for seed germination. Accordingly, Agrobacterium RS-79 and Pseudomonas BS-26 showed 100% activity. A 100% seed germination and vigor index (343.33 and 306.67) were observed in Pseudomonas BS-26 and FB-49. Degraded soil is considered a source for phosphate solubilizing and other beneficial bacteria with many traits to be used for seed germination assay.
Tomato (Solanum lycopersicum) is one of the most widely cultivated and extensively consumed horticultural crops globally. This fruit is nutritious and beneficial for human consumption as it contains lycopene and carotenoids with antioxidant properties. The main antioxidants in tomato are carotenoids, ascorbic acid, and phenolic compounds. Tomatoes have a short shelf life and are highly perishable, resulting in infections by plant pathogens causing mechanical damage before and/or after harvest. This research aimed to isolate antagonistic microorganisms and evaluate their in vitro and in vivo antagonistic activity against B. cinerea of tomato. Antagonistic microorganisms were isolated from different plant parts and tested for inhibitory effects against B. cinerea of tomatoes both in vitro and in vivo. A total of 48 antagonistic microorganisms were screened in vitro against B. cinerea on potato dextrose agar and incubated at 25°C. The mycelial growth of B. cinerea was measured post-inoculation after days 3, 5 and 7. Serratia marcescens, Bacillus pumilus and Bacillus safensis inhibited B. cinerea in vitro by 54, 52 and 51%, respectively. These isolates were further characterized and identified as the best performing antagonistic isolates. In vivo screening of S. marcescens, B. pumilus and B. safensis inhibited grey mould incidence on ‘Jam’ tomato cultivar by 83, 75 and 75%, respectively, after 7 days at 25°C. The results obtained from this study showed that biological control agents inhibited grey mould and are potential alternatives against B. cinerea of tomato.
The rhizobacterium Bacillus subtilis FZB24 registered as biocontrol agent was field tested as a promoter for salt- tolerance to two cultivars of eggplant and pepper in saline soil in the Sinai region (Egypt) under the condition of irrigation with ground saline water. The use of Bacillus subtilis for root bacterization was realized by watering the seedlings with bacterial spore-(preparation-)suspension, titer 10(8) spores/ml. Starring from 8 weeks after transplanting and for 4 weeks, fruit yield (kg/m(2)), number of fruits/plant, average fruit fresh weight, dry weight percentage and fruit size were evaluated. Compared with the unsaline-irrigated control the yield was reduced in both vegetable crops in all used cultivars, due to irrigating the plants with saline groundwater to more than 90 %. By using Bacillus subtilis FZB24 in the plots irrigated with saline groundwater, the yield increased up to 550 % in eggplants, and up to 430 % in the pepper cultivars, as compared with unbacterized ones. Also in the other plant growth parameters, significant promotions could be found in the bacterized plants in the saline plots. So, the bacterization caused 50 and 25 % reduction in salinity effect on the yield of eggplants and pepper, respectively, and consequently resulted in a remarkable salt-stress tolerance induction, which varied its degree according to the used plant species. To have insight on the mode of actions of the salt stress tolerance-inducing effect of Bacillus subtilis FZB 24, model experiments have been conducted with auxin precursors and IAA. in tomato seedlings under controlled, axenic conditions and under salt-stress conditions similar to the field experiment. Up to now, it has been hypothesized for the mode of action of Bacillus subtilis FZB24, which acts as plant growth and health promoter, and stress tolerance inducer, that the given bacterial production of auxin and auxin precursors during root colonization induces a push in the plane auxin synthesis with changing regulation of the appropriate mechanisms. In the model experiments, the pretreatment of seedlings with millimolare amounts of auxin precursors, tryptophan, indole-3-pyruvic acid or indole-3-acetic aldehyde, 75 % growth reduction in untreated seedlings under salt stress could be compensated completely after 1 week. That was not observed to the same degree after preapplication of auxin (IAA). So, the presented model experiment could support the hypothesis of salt-stress tolerance induction in Bacillus subtilis FZB24-treated plants. The results are discussed from the aspect of a general anti-stress effect of Bacillus subtilis FZB24.
Biological control of stem canker and black scurf of potatoes caused by Rhizoctonia solani and common potato scab caused by Streptomyces scabies by different suppressive strains of Bacillus subtilis was demonstrated in greenhouse and field experiments from 1993-1997. Seed potatoes were treated with different strains of Bacillus subtilis, formulated to water-dispersible granules and were planted in comparison with nontreated (control) and fungicide (Pencycuron, tolclofos-methyl) treated potatoes in greenhouse or in field against natural seed- and soil-borne infection. In addition, the influences of different edaphic and other abiotic factors were tested, e.g., various soil types, different inoculum densities, various application methods, and application rates. In the greenhouse, the disease severity of R. solani (stem canker and black scurf) was reduced up to 63 % by application of B. subtilis. The decrease of common scab (S. scabies) disease severity ranged up to 70 % with different Bacillus strains. In field trials, the occurrence of stem canker and black scurf was reduced up to 50 % and the incidence of common scab was decreased up to 67 % by use of this microbial antagonist. The bacterial treatment showed similar control effects compared to different fungicides. Moreover, the plants appeared more vigorous than nontreated plants and the yields of potato tubers were higher (on average up to 16 %).
Different Bacillus subtilis strains, isolated from soil infected with soil-borne pathogens, were tested against Pythium aphanidermatum and Phytophthora nicotianae in soilless tomato and cucumber culture systems. The B. subtilis strains tested varied in their efficacy, but none caused a constitutive suppression of the introduced root pathogens during the cultivation period. Bacterization of tomato plants with the B. subtilis strains FZB 13, FZB 24 and FZB 44 at the beginning of disease development reduced disease severity caused by P. aphanidermatum. Yield losses caused by these pathogens on tomato and cucumber could be partially compensated by bacterization with the B. subtilis strains FZB 13 and FZB 44. The bacterization of tomato plants with the B. subtilis strains FZB 13 and FZB 44 improved the total yield in the treatments without pathogen infection compared to the control. B. subtilis strains that show antifungal activity may act by inducing tolerance in the host plant.
The effect of different environmental conditions on plant growth-promoting and antifungal activities of two different Bacillus subtilis strains were studied. For this purpose, the bacteria isolated and commercialized by FZB Biotechnik GmbH Berlin were tested for their in vitro and in vivo performances. First, the strains were screened for their antagonistic abilities against phytopathogenic fungi of maize and sunflowers. It was found that antifungal activities varied according to the composition of the assay medium, pH and temperature value. Low iron availability in the assay medium increased bacterial competition for this element and resulted further in a higher antifungal activity. Further, it was found that different nitrogen sources affected differently growth and spore production by B. subtilis strains. Higher growth and spore production rates were observed when the bacteria were incubated in Landy medium or in nitrate-nitrogen rather than in ammonium-nitrogen broth. Then the efficacy of the bacteria to promote plant health and growth was evaluated. These studies were conducted in culture solution and in soil under different ecological factors. The results suggest that these bacterial strains may produce substances that enhance plant growth and yield on maize and sunflowers. However, the results also showed that in vitro antibiotic activity did not always correlate with disease reduction on maize in greenhouse and field trials. Only in the case of the biological control of Sclerotinia sclerotiorum on sunflowers in field trials, a satisfying effectiveness was achieved. The results are discussed with regard to the general effect of plant growth and health-promoting substances produced by Bacillus subtilis.