Application Of Endophytic Bacteria Research Articles

Application of Endophytic Bacteria using In vitro Technique to Increase Vigour of Shallots (Allium cepa L.) based on Inoculation Time

Shallot is one of the important horticultural commodities in Indonesia. Besides having many benefits, the shallot is also the main ingredient in various traditional dishes in Indonesia. A significant increase in healthy shallot production is needed to meet the increasing demand every year. The aim of this study was to obtain the best strain of endophytic bacteria and inoculation time for increasing shallot vigour through in vitro. This study used a factorial completely randomized design with two factors, the type of bacteria and the time of inoculation which was divided into 3 stages. The first stage consisted of three collections of bacteria (GO53, IB15, S12) with 12 and 24 hours of inoculation. The second stage consisted of two collections bacteria (GO53, IB15) with 4 and 6 hours of inoculation. The third stage consisted of one collection bacteria (GO53) and 4 bacterial strains isolated from shallot (T4(2), T5, T8(1), T8(2)) with 2 and 4 hours of inoculation. The results showed GO53 and T4(2) with 2 hours of inoculation were the best types of endophytic bacteria to increase vigour. The explants in this treatment survived the longest, had more shoots and leaves than the control, and induced root formation more quickly.

Effectivity of the Consortium of Rhizobacteria and Endophytic Bacteria to Controls the White Tip Disease of Rice Caused by Seed-Borne Nematode Aphelenchoides besseyi

<p>Aphelenchoides besseyi is a seed-borne nematode that causes white-tip disease in rice. Yield losses due to this nematode infection reach 30-50% in various countries. This research aimed to investigate the effectiveness of a consortium of rhizobacteria and endophytic bacteria in controlling the white tip disease while promoting the growth of rice seeds infected by A. besseyi. The experiments conducted were a bacterial compatibility test, in vitro test to examine the nematicidal activity of bacterial consortium, and an in vivo test to investigate the effectiveness of bacterial consortium to suppress disease occurrence and promote the growth of rice. The research was conducted at the Plant Protection Laboratory, Faculty of Agriculture, University of Jember from July 2020 to December 2020. The experiments used a randomized block design with five concentration levels of bacterial suspension of 20%, 40%, 60%, 80%, and 100%. The results showed that the endophytic bacterial consortium effectively controlled the growth of A. besseyi up to 80% compared to control. Furthermore, the percentage of white tip symptoms in the control plant reached 83%. In comparison, it was observed lower in a range from 74.5% to 25% in plants treated with a suspension of endophytic bacterial consortium. The control plant’s symptom length reached 3.94 cm, while the average symptom length in the treated plant ranged from 3.41 cm to 1.50 cm. The application of endophytic bacteria was also found to accelerate plant growth by increasing plant height and root length of the rice plant. The effectiveness of a consortium of rhizobacteria and endophytic bacteria to control white tip disease while increasing plant growth of rice in Indonesia is first reported in this manuscript.</p>

Metabolomics Analyses Reveal Metabolites Affected by Plant Growth-Promoting Endophytic Bacteria in Roots of the Halophyte Mesembryanthemum crystallinum.

Mesembryanthemum crystallinum L. (common ice plant) is an edible halophyte. However, if ice plants are used to phytoremediate salinity soil, there are problems of slow initial growth, and a long period before active NaCl uptake occurs under higher salinity conditions. Application of endophytic bacteria may improve the problem, but there remain gaps in our understanding of how endophytic bacteria affect the growth and the biochemical and physiological characteristics of ice plants. The aims of this study were to identify growth-promoting endophytic bacteria from the roots of ice plants and to document the metabolomic response of ice plants after application of selected endophytic bacteria. Two plant growth-promoting endophytic bacteria were selected on the basis of their ability to promote ice plant growth. The two strains putatively identified as Microbacterium spp. and Streptomyces spp. significantly promoted ice plant growth, at 2-times and 2.5-times, respectively, compared with the control and also affected the metabolome of ice plants. The strain of Microbacterium spp. resulted in increased contents of metabolites related to the tricarboxylic acid cycle and photosynthesis. The effects of salt stress were alleviated in ice plants inoculated with the endobacterial strains, compared with uninoculated plants. A deeper understanding of the complex interplay among plant metabolites will be useful for developing microbe-assisted soil phytoremediation strategies, using Mesembryanthemum species.

Antifungal mechanism of Bacillus amyloliquefaciens strain GKT04 against Fusarium wilt revealed using genomic and transcriptomic analyses.

The application of endophytic bacteria, particularly members of the genus Bacillus, offers a promising strategy for the biocontrol of plant fungal diseases, owing to their sustainability and ecological safety. Although multiple secondary metabolites that demonstrate antifungal capacity have been identified in diverse endophytic bacteria, the regulatory mechanisms of their biosynthesis remain largely unknown. To elucidate this, we sequenced the entire genome of Bacillus amyloliquefaciens GKT04, a strain isolated from banana root, which showed high inhibitory activity against Fusarium oxysporum f. sp. cubense race 4 (FOC4). The GKT04 genome consists of a circular chromosome and a circular plasmid, which harbors 4,087 protein‐coding genes and 113 RNA genes. Eight gene clusters that could potentially encode antifungal components were identified. We further applied RNA‐Seq analysis to survey genome‐wide changes in the gene expression of strain GKT04 during its inhibition of FOC4. In total, 575 upregulated and 242 downregulated genes enriched in several amino acid and carbohydrate metabolism pathways were identified. Specifically, gene clusters associated with difficidin, bacillibactin, and bacilysin were significantly upregulated, and their gene regulatory networks were constructed. Our work thereby provides insights into the genomic features and gene expression patterns of this B. amyloliquefaciens strain, which presents an excellent potential for the biocontrol of Fusarium wilt.

Endophytic bacterial consortia as biocontrol of purple blotch and plant growth promoters of shallots

Endophytic bacteria have been reported to have roles as biocontrol agents and plant growth promoters. The application of endophytic bacteria in the form of mixed culture [consortia] will provide better effectiveness than when applied alone. This study aimed to obtain a consortium of endophytic bacteria that is effective as a biological control for purple blotch [Alternariaporri], promote the growth and yield of shallots. The research was arranged in a completely randomized design [CRD] consisting of 7 treatments with three replications. The consortium used was a mixture of two strains of Bacillus sp., two strains of B. cereus, two strains of Serratia marcescens, Bacillus subtilis, Azotobacter, Azospirillum, and P. fluorescens. The variables observed in this study included disease progression [incubation period, disease incidence, and disease severity], plant growth [number of leaves and plant height], and yield [fresh weight and dry weight of bulbs]. The results showed that the C consortium [Bacillus sp. strain SJI, Bacillus sp. strain HI, Serratia marcescens strain ULG1E4 and Serratia marcescens strain JBIE3] and G consortium [Bacillus sp. strain SJI, Bacillus sp. strain HI, Bacillus subtilis, Pseudomonas fluorescens, Serratia marcescens strain ULG1E4 and Serratiamarcescens strain JBIE3] were the best consortia in suppressing purple blotch disease, as well as in improving the growth and yield of shallots.

Alleviation of Salinity Stress in Peanut by Application of Endophytic Bacteria.

The development of salinity affects 7% of the world’s land surface, acting as a major constraint to crop productivity. This study attempted to use the co-evolving endophytes of peanut to alleviate salinity stress and enhance the yield of peanut. Diverse and different tissue colonizing endophytes were isolated from peanut and screened in vitro by seed germination bioassay imposing gradients of salinity, with two cultivars TG37A (susceptible) and GG2 (moderately resistant), in potted conditions using saline irrigation water. Finally, nine endophytes capable of producing IAA and ACC-deaminase, promoting root growth and yield in potted conditions were selected for further evaluation in field conditions. They were evaluated with saline water (1.5–2.0 dS/m) in saline soil with susceptible cultivar TG37A. Simultaneously, three endophytes (Bacillus firmus J22N; Bacillus tequilensis SEN15N; and Bacillus sp. REN51N) were evaluated with two cultivars, GG2 and TG37A, during rainy and post-rainy seasons with elevated salinity. The application of endophytes like Bacillus firmus J22N and Bacillus sp. REN51N enhanced the pod and haulm yield of peanuts by 14–19% across cultivars, salinity, and seasons. In addition, there was significant modulation in parameters like relative water content; production of enzymes like superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT), ascorbate peroxidase (APX), lipid peroxidase (POD), and H2O2 content in leaf; and uptake of potassium. The activities of the enzymes involved in scavenging reactive oxygen species (ROS) increased with salinity, and further increased with endophytes like Bacillus firmus J22N, Bacillus tequilensis SEN15N, and Bacillus sp. REN51N. There was an enhanced accumulation of proline, reduced level of phenol and H2O2, and enhanced uptake of potassium with the inoculation of endophytes. This improved scavenging capacity of plants by endophytic modulation of ROS scavengers, uptake of K, production of ACC deaminase and IAA, root and biomass growth, modulation in relative water content, and enhanced accumulation of osmoprotectant might be the reasons of alleviation of salinity stress. Endophytes could have alleviated salinity stress in peanuts, indicating the mechanisms and potential of peanuts at the field level. These endophytes could be applied to bring agricultural sustainability to salinity-affected areas in the future. Furthermore, few genera viz. Kocuria, Brevundimonas, Agrococcus, Dietzia, and Kytococcus were observed in peanut tissue for the first time.

Efficiency of Endophytic bacterial culture on yield and yield attributes of groundnut

Field experiments were carried out for three consecutive years conducted during 2016, 2018 and 2019 during kharif season at Zonal Agricultural and Horticultural Research Station, Babbur farm, Hiriyur, Karnataka, India to study the alleviation of moisture-deficit stress in groundnut by application of endophytic bacteria under rainfed conditions. The experiment was laid out in randomized block design with three replication and eight treatments. The pooled results of three years revealed that treatment having DGREB-3 culture with intercultural operations significantly recorded higher pod yield (1022 kg ha-1) as compared to control (693 kg ha-1) and it is on par with any DGREB culture (T2) with two intercultural operations (909 kg ha-1). Any DGREB culture with two intercultural operations significantly recorded highest nodulations at 30 and 60 days (50.2 and 57.8) as compared to control (20.6 and 33.7). In case of higher gross returns (Rs. 46,565), net returns (Rs. 16,997) were recorded with DGREB-3 culture with intercultural operations. Whereas highest B:C (1.66) was recorded with any DGREB culture with two intercultural operations.

Formulasi Konsorsium Bakteri Endofit untuk Menekan Infeksi Nematoda Puru Akar Meloidogyne incognita pada Tomat

The root-knot nematodes ( Meloidogyne incognita ) infection can cause a significant yield loss in tomato plants. One of the environmentally friendly efforts to control this nematode is through the application of endophytic bacteria. The application of endophytic bacteria in the form of a consortium was reported to be more effective than the application using a single isolate. This study aims to test the effectiveness of the endophytic bacteria consortium formula in suppressing M. incognita infection in tomato plants. The research stages were the selection of the consortium of endophytic bacteria as a growth promoter for tomato plants infected with M. incognita . The best performing consortium was formulated using 100 g of grass compost + 100 g vermicompost + 10 ml molasses + 1 g peptone and 50 ml distilled water. The test of bacterial cell viability in the endophytic formula was carried out for 20 weeks. The formula made was tested for its performance as a biocontrol agent against M. incognita in tomato plants. The results showed that three consortia gave the best results as growth promoters of M. incognita infected tomatoes, namely TmtN5, TmtN2, and GsgN2. The three of them survived the formula with log CFU at week 20 of 6.07 (TmtN5), 5.56 (TmtN2), and 6.11 (GsgN2). This formula can suppress the nematode population on tomato plants' roots and suppress the number of root knots in tomato plants. This study provides information that there are three consortia of endophytic bacteria (TmtN5, TmtN2, and GsgN2), which have the potential to become biological control agents for root-purulent nematodes.

First Record of Leaf Spot Disease on Costus speciosus Caused by Nigrospora oryzae in Hainan, China.

Costus speciosus (Koen.) Smith has been an important medicinal agent in the various traditional and folk systems of medicine in southern China. In September 2018, leaf spot disease was detected on C. speciosus plants in Chengmai County, Hainan Province. A survey of C. speciosus plants revealed that the disease caused serious damage during the typhoon season of September to November in Hainan Province, with 80 to85% incidence in plants. Early symptoms were yellow-to-brown, irregular-shaped lesions on the leaf margin or tip. After several days, lesions expanded along the mid-vein until the entire leaf was destroyed. Then, the infected leaves turned gray brown, leading to defoliation. Heavily infected leaves became dry and died. The pathogen was consistently isolated from the lesions and pure single-spore cultures were obtained. Twenty pieces of diseased leaf samples were plated and seven pieces yielded fungal colonies after 5 to 6 days of incubation at 25 °C. Colonies on potato dextrose agar (PDA) were white and later became gray to black. Conidia were unicellular, terminal, black, elliptical that measured 10 to 13 (length) × 12 to 16 (width) μm (n=30), growing aerial mycelium covering the entire petri dish (9 cm in diameter). The morphological characteristics and measurements of this fungal pathogen matched the previous descriptions of Nigrospora oryzae (Wang et al. 2017). To confirm identity the internal transcribed spacer (ITS) region of the ribosomal DNA was amplified using primers ITS1/ITS4 (Mills, P. R., et al. 1992), and the 530-bp product (GenBank Accession No. MK280694) of the ITS showed 99% sequence identity to N. oryzae isolates TLFa21 (GenBank Accession No. MH790146) and xsd08022 (GenBank Accession No. EU918714). Pathogenicity tests were conducted. Three leaves of three C. speciosus plants were wounded and inoculated with mycelial plugs (5×5mm) , and an additional five plants were inoculated with PDA plugs as a control. All plants were placed in the field and temperature ranged from 23 to 29°C. Ten days after inoculation, all the inoculated plants showed typical leaf spot symptoms, a yellow-to-brown mildew appeared at the points of inoculation. No symptoms were observed on the controls. The fungus was re-isolated from the infected tissues, fulfilling Koch's postulates. N. oryzae was previously reported as the causal agent of leaf spot on cotton (Zhang. et al. 2012), dendrobium candidum (Wu. et al. 2014) and Aloe vera (Zhai. et al. 2013) in china. To our knowledge, this is the first report of leaf spot of C. speciosus caused by N. oryzae in China. The project was partially founded by Hainan Provincial Research Institute of technology development projects (Screening and application of endophytic bacteria with high resistance to Fusarium Wilt of Sauropus androgynus), Hainan Provincial Key Laboratory for Vegetables and Biology，Hainan Provincial Engineering Research Center for Melon and Vegetable Breeding, Major scientific and technological projects in Hainan Province(ZDKJ2017001)，Third Survey and Collection of Crop Germplasm Resources in China, Collection, identification and preservation of pathogenic bacteria of inverted season vegetable in Hainan.

ISOLASI DAN IDENTIFIKASI BAKTERI ENDOFIT DARI TANAMAN PADI (Oryza sativa) SEBAGAI PENGENDALI PENYAKIT HAWAR DAUN BAKTERI AKIBAT Xanthomonas oryzae pv. oryzae

Rice cultivation often face obstacles, and one of them is bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo). The application of endophytic bacteria is one of solutions to overcome this problem. Endophytic bacteria are non-pathogenic bacteria, which live in plant tissues. These bacteria could be isolated from the plant tissues. They may adapt to the plant tissues and produce antibiosis that could increase the plant resistance. Therefore, objectives of the research were to isolate the endophytic bacteria from healthy plant tissues and to identify them through morphology, physiology, biochemistry, and molecular. Method of the research was explorative along with three principal activities, such as isolation, selection, and identification on the potential endophytic bacteria. The isolation of the endophytic bacteria from healthy rice tissues has resulted 53 isolates and five of them have antagonistic ability in vitro against Xoo. Isolate ak9 has the highest antagonistic ability, 7.67 mm, in comparison with other isolates. Results of identification showed that those five potential bacteria have close relations, such as da3 with Bacillus cereus, isolate ak9 with Burkholderia sp., isolate ak30 with Enterobacter sp and isolate da9, as well as ak15 are Corynebacterium sp.

ISOLASI DAN IDENTIFIKASI BAKTERI ENDOFIT DARI TANAMAN PADI (Oryza sativa) SEBAGAI PENGENDALI PENYAKIT HAWAR DAUN BAKTERI AKIBAT Xanthomonas oryzae pv. oryzae

Rice cultivation often face obstacles, and one of them is bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo). The application of endophytic bacteria is one of solutions to overcome this problem. Endophytic bacteria are non-pathogenic bacteria, which live in plant tissues. These bacteria could be isolated from the plant tissues. They may adapt to the plant tissues and produce antibiosis that could increase the plant resistance. Therefore, objectives of the research were to isolate the endophytic bacteria from healthy plant tissues and to identify them through morphology, physiology, biochemistry, and molecular. Method of the research was explorative along with three principal activities, such as isolation, selection, and identification on the potential endophytic bacteria. The isolation of the endophytic bacteria from healthy rice tissues has resulted 53 isolates and five of them have antagonistic ability in vitro against Xoo. Isolate ak9 has the highest antagonistic ability, 7.67 mm, in comparison with other isolates. Results of identification showed that those five potential bacteria have close relations, such as da3 with Bacillus cereus, isolate ak9 with Burkholderia sp., isolate ak30 with Enterobacter sp and isolate da9, as well as ak15 are Corynebacterium sp.

Use of endophytic bacteria from roots of Cyperus rotundus for biocontrol of Meloidogyne incognita

Mardhiana, Pradana AP, Adiwena M, Santoso D, Wijaya R, Murtilaksono A. 2017. Use of endophytic bacteria from roots of Cyperus rotundus for biocontrol of Meloidogyne incognita. Biodiversitas 18: 1308-1315. Yield loss due to M. incognita infection in tomato plants cultivation can reach 60%. The problem is able to be solved through the application of endophytic bacteria. In this study, endophytic bacteria from root Cyperus rotundus were isolated using Tryptic Soy Agar media. The bacteria isolates were then tested their safety against plants and mammals. The phenotypic and physiological properties of selected isolates were characterized and tested to know their resistance to antibiotics, and their ability in suppressing the infection rate of M. incognita on tomato. Eighteen bacterial isolates were obtained and 8 of them are categorized as safe bacteria for plants and mammals, which could be used in further tests. A result of the physiological test showed that bacterial isolates were able to produce protease enzyme (87.5%), chitinase enzyme (62.5%), and HCN (37.5%), having urease activity (75%) and could dissolve phosphate (87.5%). Based on the test results, all endophytic bacteria effectively increased tomato growth and suppressed the severity of M. incognita infection with the most stable isolate as a biocontrol agent of M. incognita was CRS16.

Bahasa Indonesia

One of the factors affected production of tomato is the incidence of bacterial wilt disease caused by Ralstonia solanacearum . An alternative control to manage the disease which is environmentally friendly is the use of biocontrol agents. Application of endophytic bacteria ( Staphylococcus epidermidis BC4) and plant growth promoting rhizobacteria ( Pseudomonas fluorescens RH4003 and Bacillus subtilis AB89) as biocontrol of tomato bacterial wilt was expected to be an alternative method. The objective of this study is to evaluate the interaction among endophytic bacteria and PGPR to suppress the development of bacterial wilt disease ( R. solanacearum ) and promoting the growth of tomato. Bacterial treatment which caused the highest suppression on disease incidence was single application of P. fluorescens RH4003. Disease index caused by S. epidermidis BC4 and P. fluorescens RH4003 applied individually was up to 41.18 dan 45.88%, respectively. Interaction between the endophytic bacteria and both of the PGPRs were antagonistic.

Application of endophytic bacteria for controlling anthracnose disease (Colletotrichum lindemuthianum) on bean plants

Over 100 endophytic bacterial isolates were isolated from surface-sterilised roots of the Fabaceae family in East Azerbaijan farms. These isolates were screened for their in vitro biocontrol activity against Colletotrichum lindemuthianum by dual culture technique using potato dextrose agar (PDA) medium. Eight bacterial isolates (Bacillus subtilis subsp. subtilis, Bacillus atrophaeus, B. tequilensis, B. subtilis subsp. spizizenii, Streptomyces cyaneofuscatus, S. flavofuscus, S. parvus, S. acrimycini) showed promising inhibition on mycelial growth of C. lindemuthianum , and thus, these isolates were selected for greenhouse experiments. The disease control rate using these selected endophytic bacteria was varied from 40 to 76.80% in greenhouse without any negative effects on different growth performance, suggesting that these selected endophytic bacteria are potential to be developed as biocontrol agents.