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Kong P, Hong C. Evaluation of 1021Bp, a close relative of Pseudomonas eucalypticola, for potential of plant growth promotion, fungal pathogen suppression and boxwood blight control. BMC Microbiol 2024; 24:346. [PMID: 39277720 PMCID: PMC11401285 DOI: 10.1186/s12866-024-03497-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 09/05/2024] [Indexed: 09/17/2024] Open
Abstract
BACKGROUND Pseudomonas eucalypticola, a new species of the P. fluorescens group that generates most Pseudomonas-based biocontrol agents, has not been found in any plants other than Eucalyptus dunnii leaves. Except for antagonism to the growth of a few fungi, its features in plant growth promotion and disease control have not been evaluated. Here, we identified a similar species of P. eucalypticola, 1021Bp, from endophyte cultures of healthy leaves of English boxwood (Buxus sempervirens 'Suffruticosa') and investigated its antifungal activity, plant growth promotion traits, and potential for boxwood blight control. RESULTS Colorimetric or plate assays showed the properties of 1021Bp in nitrogen fixation, phosphate solubilization, and production of indole-3-acetic acid (IAA) and siderophores, as well as the growth suppression of all five plant fungal pathogens, including causal agents of widespread plant diseases, gray mold, and anthracnose. Boxwood plant leaves received 87.4% and 65.8% protection from infection when sprayed with cell-free cultural supernatant (CFS) but not the resuspended bacterial cells at 108-9/mL of 1021Bp at one and seven days before inoculation (dbi) with boxwood blight pathogen, Calonectria pseudonaviculata, at 5 × 104 spores/mL. They also received similarly high protection with the 1021Bp cell culture without separation of cells and CFS at 14 dbi (67.5%), suggesting a key role of 1021Bp metabolites in disease control. CONCLUSIONS Given the features of plant growth and health and its similarity to P. eucalypticola with the P. fluorescens lineage, 1021Bp has great potential to be developed as a safe and environmentally friendly biofungicide and biofertilizer. However, its metabolites are the major contributors to 1021Bp activity for plant growth and health. Application with the bacterial cells alone, especially with nonionic surfactants, may result in poor performance unless survival conditions are present.
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Affiliation(s)
- Ping Kong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, USA.
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, USA
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Meng X, Luo Y, Zhao X, Fu Y, Zou L, Cai H, Zhou Y, Tu M. Isolation, Identification, and Biocontrol Mechanisms of Endophytic Burkholderia arboris DHR18 from Rubber Tree against Red Root Rot Disease. Microorganisms 2024; 12:1793. [PMID: 39338468 PMCID: PMC11433949 DOI: 10.3390/microorganisms12091793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Revised: 08/23/2024] [Accepted: 08/26/2024] [Indexed: 09/30/2024] Open
Abstract
Red root rot disease is a devastating fungal disease of rubber trees caused by Ganoderma pseudoferreum (Wakef). Biocontrols using beneficial microorganisms are safe and sustainable. We isolated a DHR18 endophytic bacterium from a healthy rubber tree to obtain a new efficient antagonistic bacterium for red root rot disease affecting rubber trees and evaluated the mechanism of action involved using a double culture assay, genome annotation analysis, and the ethyl acetate extraction method. The results revealed that the DHR18 strain inhibits G. pseudoferreum growth and has broad-spectrum antifungal activity by secreting cell wall hydrolases (proteases and chitinases), indole-3-acetic acid, and siderophores. Furthermore, it fixes nitrogen and is involved in biofilm formation and phosphate solubilisation, improving disease resistance and tree growth. The results showed that the antifungal substances secreted by DHR18 are mainly lipopeptides. Simultaneously, DHR18 enhanced the rubber tree resistance to G. pseudoferreum by increasing the activities of defence enzymes superoxide dismutase, phenylalanine ammonia lyase, peroxidase, catalase, and polyphenol oxidase. The results indicate that B. arboris DHR18 has biocontrol potential and could be used as a candidate strain for the control of red root rot disease in rubber trees.
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Affiliation(s)
- Xiangjia Meng
- National Key Laboratory for Tropical Crop Breeding, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China; (X.M.); (Y.L.); (X.Z.); (Y.F.); (H.C.)
- School of Agriculture, Yangtze University, Jingzhou 434000, China
| | - Youhong Luo
- National Key Laboratory for Tropical Crop Breeding, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China; (X.M.); (Y.L.); (X.Z.); (Y.F.); (H.C.)
- School of Agriculture, Yangtze University, Jingzhou 434000, China
| | - Xinyang Zhao
- National Key Laboratory for Tropical Crop Breeding, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China; (X.M.); (Y.L.); (X.Z.); (Y.F.); (H.C.)
- School of Agriculture, Yangtze University, Jingzhou 434000, China
| | - Yongwei Fu
- National Key Laboratory for Tropical Crop Breeding, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China; (X.M.); (Y.L.); (X.Z.); (Y.F.); (H.C.)
| | - Lifang Zou
- Shanghai Collaborative Innovation Centre of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Haibin Cai
- National Key Laboratory for Tropical Crop Breeding, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China; (X.M.); (Y.L.); (X.Z.); (Y.F.); (H.C.)
| | - Yi Zhou
- School of Agriculture, Yangtze University, Jingzhou 434000, China
| | - Min Tu
- National Key Laboratory for Tropical Crop Breeding, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China; (X.M.); (Y.L.); (X.Z.); (Y.F.); (H.C.)
- Sanya Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572020, China
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Pandey P, Tripathi A, Dwivedi S, Lal K, Jhang T. Deciphering the mechanisms, hormonal signaling, and potential applications of endophytic microbes to mediate stress tolerance in medicinal plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1250020. [PMID: 38034581 PMCID: PMC10684941 DOI: 10.3389/fpls.2023.1250020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023]
Abstract
The global healthcare market in the post-pandemic era emphasizes a constant pursuit of therapeutic, adaptogenic, and immune booster drugs. Medicinal plants are the only natural resource to meet this by supplying an array of bioactive secondary metabolites in an economic, greener and sustainable manner. Driven by the thrust in demand for natural immunity imparting nutraceutical and life-saving plant-derived drugs, the acreage for commercial cultivation of medicinal plants has dramatically increased in recent years. Limited resources of land and water, low productivity, poor soil fertility coupled with climate change, and biotic (bacteria, fungi, insects, viruses, nematodes) and abiotic (temperature, drought, salinity, waterlogging, and metal toxicity) stress necessitate medicinal plant productivity enhancement through sustainable strategies. Plants evolved intricate physiological (membrane integrity, organelle structural changes, osmotic adjustments, cell and tissue survival, reclamation, increased root-shoot ratio, antibiosis, hypersensitivity, etc.), biochemical (phytohormones synthesis, proline, protein levels, antioxidant enzymes accumulation, ion exclusion, generation of heat-shock proteins, synthesis of allelochemicals. etc.), and cellular (sensing of stress signals, signaling pathways, modulating expression of stress-responsive genes and proteins, etc.) mechanisms to combat stresses. Endophytes, colonizing in different plant tissues, synthesize novel bioactive compounds that medicinal plants can harness to mitigate environmental cues, thus making the agroecosystems self-sufficient toward green and sustainable approaches. Medicinal plants with a host set of metabolites and endophytes with another set of secondary metabolites interact in a highly complex manner involving adaptive mechanisms, including appropriate cellular responses triggered by stimuli received from the sensors situated on the cytoplasm and transmitting signals to the transcriptional machinery in the nucleus to withstand a stressful environment effectively. Signaling pathways serve as a crucial nexus for sensing stress and establishing plants' proper molecular and cellular responses. However, the underlying mechanisms and critical signaling pathways triggered by endophytic microbes are meager. This review comprehends the diversity of endophytes in medicinal plants and endophyte-mediated plant-microbe interactions for biotic and abiotic stress tolerance in medicinal plants by understanding complex adaptive physiological mechanisms and signaling cascades involving defined molecular and cellular responses. Leveraging this knowledge, researchers can design specific microbial formulations that optimize plant health, increase nutrient uptake, boost crop yields, and support a resilient, sustainable agricultural system.
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Affiliation(s)
- Praveen Pandey
- Microbial Technology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
- Division of Plant Breeding and Genetic Resource Conservation, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Arpita Tripathi
- Microbial Technology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
- Faculty of Education, Teerthanker Mahaveer University, Moradabad, India
| | - Shweta Dwivedi
- Division of Plant Breeding and Genetic Resource Conservation, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Kanhaiya Lal
- Division of Plant Breeding and Genetic Resource Conservation, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Tripta Jhang
- Division of Plant Breeding and Genetic Resource Conservation, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
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Li X, Omolehin O, Hemmings G, Tseng HT, Taylor A, Taylor C, Kong P, Daughtrey M, Luster D, Gouker F, Hong C. Boxwood phyllosphere fungal and bacterial communities and their differential responses to film-forming anti-desiccants. BMC Microbiol 2023; 23:219. [PMID: 37573307 PMCID: PMC10422719 DOI: 10.1186/s12866-023-02956-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/21/2023] [Indexed: 08/14/2023] Open
Abstract
BACKGROUND Anti-desiccant is a class of agrochemicals widely used to protect plants from water stresses, rapid temperature variations, heat and sunburn, frost and freeze damages, transplant shock, and pathogen and pest attack. Although anti-desiccants are generally considered non-toxic to organisms, it is unclear whether they may impact the phyllosphere microbial communities. In this study, three film-forming anti-desiccant products, TransFilm, Vapor Gard, and Wilt-Pruf were applied to the canopy of two boxwood cultivars 'Vardar Valley' and 'Justin Brouwers' on April 13 and August 26, 2021. Shoot samples were collected from boxwood plants treated with each of the three products, as well as nontreated control on June 16, August 26 (before the second treatment), and October 18. Microbial and plant genomic DNA was isolated together and 16S rRNA gene and the extended internal transcribed spacer regions were amplified with PCR and sequenced on a Nanopore MinION platform for bacterial and fungal identification. RESULTS Bacterial communities were more diverse than fungal communities. At the phylum level, the boxwood phyllosphere was dominated by Proteobacteria and Ascomycota; at the genus level, Methylobacterium and Shiraia were the most abundant bacteria and fungi, respectively. Among the three film-forming anti-desiccants, Vapor Gard and Wilt-Pruf had more impact than TransFilm on the microbial communities. Specifically, broader impacts were observed on fungal than bacterial community composition and structure, with most affected fungi being suppressed while bacteria promoted. CONCLUSION This study addressed several major knowledge gaps regarding boxwood phyllosphere microbiota and the impact of anti-desiccants on plant microbiome. We identified diverse microbial communities of boxwood, a major evergreen woody crop and an iconic landscape plant. We also found differential effects of three film-forming anti-desiccants on the composition and structure of bacterial and fungal communities. These findings advanced our understanding of the associated microbiome of this landmark plant, enabling growers to fully utilize the potentials of microbiome and three anti-desiccants in improving boxwood health and productivity.
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Affiliation(s)
- Xiaoping Li
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA, USA.
| | - Olanike Omolehin
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA, USA
| | - Ginger Hemmings
- Plant Industry Division, North Carolina Department of Agriculture and Consumer Services, Dobson, NC, USA
| | - Hsien Tzer Tseng
- Plant Industry Division, North Carolina Department of Agriculture and Consumer Services, Raleigh, NC, USA
| | - Amanda Taylor
- North Carolina University Cooperative Extension, Morganton, NC, USA
| | - Chad Taylor
- Plant Industry Division, North Carolina Department of Agriculture and Consumer Services, Boone, NC, USA
| | - Ping Kong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA, USA
| | - Margery Daughtrey
- Long Island Horticultural Research and Extension Center, Cornell University, Riverhead, NY, USA
| | - Douglas Luster
- Foreign Disease-Weed Science Research Unit, USDA-ARS-NEA, Fort Detrick, MD, USA
| | - Fred Gouker
- U.S. National Arboretum, Floral and Nursery Plants Research Unit, USDA-ARS, Beltsville, MD, USA
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA, USA
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Watts D, Palombo EA, Jaimes Castillo A, Zaferanloo B. Endophytes in Agriculture: Potential to Improve Yields and Tolerances of Agricultural Crops. Microorganisms 2023; 11:1276. [PMID: 37317250 DOI: 10.3390/microorganisms11051276] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 06/16/2023] Open
Abstract
Endophytic fungi and bacteria live asymptomatically within plant tissues. In recent decades, research on endophytes has revealed that their significant role in promoting plants as endophytes has been shown to enhance nutrient uptake, stress tolerance, and disease resistance in the host plants, resulting in improved crop yields. Evidence shows that endophytes can provide improved tolerances to salinity, moisture, and drought conditions, highlighting the capacity to farm them in marginal land with the use of endophyte-based strategies. Furthermore, endophytes offer a sustainable alternative to traditional agricultural practices, reducing the need for synthetic fertilizers and pesticides, and in turn reducing the risks associated with chemical treatments. In this review, we summarise the current knowledge on endophytes in agriculture, highlighting their potential as a sustainable solution for improving crop productivity and general plant health. This review outlines key nutrient, environmental, and biotic stressors, providing examples of endophytes mitigating the effects of stress. We also discuss the challenges associated with the use of endophytes in agriculture and the need for further research to fully realise their potential.
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Affiliation(s)
- Declan Watts
- Department of Chemistry and Biotechnology, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Enzo A Palombo
- Department of Chemistry and Biotechnology, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Alex Jaimes Castillo
- Department of Chemistry and Biotechnology, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Bita Zaferanloo
- Department of Chemistry and Biotechnology, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
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Wang D, Luo WZ, Zhang DD, Li R, Kong ZQ, Song J, Dai XF, Alkan N, Chen JY. Insights into the Biocontrol Function of a Burkholderia gladioli Strain against Botrytis cinerea. Microbiol Spectr 2023; 11:e0480522. [PMID: 36861984 PMCID: PMC10101029 DOI: 10.1128/spectrum.04805-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/10/2023] [Indexed: 03/03/2023] Open
Abstract
Pathogenic fungi are the main cause of yield loss and postharvest loss of crops. In recent years, some antifungal microorganisms have been exploited and applied to prevent and control pathogenic fungi. In this study, an antagonistic bacteria KRS027 isolated from the soil rhizosphere of a healthy cotton plant from an infected field was identified as Burkholderia gladioli by morphological identification, multilocus sequence analysis, and typing (MLSA-MLST) and physiobiochemical examinations. KRS027 showed broad spectrum antifungal activity against various phytopathogenic fungi by secreting soluble and volatile compounds. KRS027 also has the characteristics of plant growth promotion (PGP) including nitrogen fixation, phosphate, and potassium solubilization, production of siderophores, and various enzymes. KRS027 is not only proven safe by inoculation of tobacco leaves and hemolysis test but also could effectively protect tobacco and table grapes against gray mold disease caused by Botrytis cinerea. Furthermore, KRS027 can trigger plant immunity by inducing systemic resistance (ISR) activated by salicylic acid- (SA), jasmonic acid- (JA), and ethylene (ET)-dependent signaling pathways. The extracellular metabolites and volatile organic compounds (VOCs) of KRS027 affected the colony extension and hyphal development by downregulation of melanin biosynthesis and upregulation of vesicle transport, G protein subunit 1, mitochondrial oxidative phosphorylation, disturbance of autophagy process, and degrading the cell wall of B. cinerea. These results demonstrated that B. gladioli KRS027 would likely become a promising biocontrol and biofertilizer agent against fungal diseases, including B. cinerea, and would promote plant growth. IMPORTANCE Searching the economical, eco-friendly and efficient biological control measures is the key to protecting crops from pathogenic fungi. The species of Burkholderia genus are widespread in the natural environment, of which nonpathogenic members have been reported to have great potential for biological control agents and biofertilizers for agricultural application. Burkholderia gladioli strains, however, need more study and application in the control of pathogenic fungi, plant growth promotion, and induced systemic resistance (ISR). In this study, we found that a B. gladioli strain KRS027 has broad spectrum antifungal activity, especially in suppressing the incidence of gray mold disease caused by Botrytis cinerea, and can stimulate plant immunity response via ISR activated by salicylic acid- (SA), jasmonic acid- (JA), and ethylene (ET)-dependent signaling pathways. These results indicate that B. gladioli KRS027 may be a promising biocontrol and biofertilizer microorganism resource in agricultural applications.
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Affiliation(s)
- Dan Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, China
| | - Wan-Zhen Luo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Agronomy, Xinjiang Agricultural University, Urumqi, China
| | - Dan-Dan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ran Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, China
| | - Zhi-Qiang Kong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jian Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiao-Feng Dai
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, China
| | - Noam Alkan
- Department of Postharvest Science, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Jie-Yin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, China
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Li X, Tseng HT, Hemmings G, Omolehin O, Taylor C, Taylor A, Kong P, Daughtrey M, Gouker F, Hong C. Characterization of Boxwood Shoot Bacterial Communities and Potential Impact from Fungicide Treatments. Microbiol Spectr 2023; 11:e0416322. [PMID: 36853063 PMCID: PMC10100737 DOI: 10.1128/spectrum.04163-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 02/10/2023] [Indexed: 03/01/2023] Open
Abstract
Phyllosphere bacterial communities play important roles in plant fitness and growth. The objective of this study was to characterize the epiphytic and endophytic bacterial communities of boxwood shoots and determine how they may respond to commonly used fungicides. In early summer and early fall, shoot samples were collected immediately before and 1, 7, and 14 days after three fungicides containing chlorothalonil and/or propiconazole were applied to the canopy. Total genomic DNA from shoot surface washings and surface-sterilized shoot tissues was used as the template for 16S rRNA metabarcoding, and the amplicons were sequenced on a Nanopore MinION sequencer to characterize the epiphytic and endophytic communities. The bacterial communities were phylogenetically more diverse on the boxwood shoot surface than in the internal tissue, although the two communities shared 12.7% of the total 1,649 identified genera. The most abundant epiphytes were Methylobacterium and Pantoea, while Stenotrophomonas and Brevundimonas were the dominant endophytes. Fungicide treatments had strong impacts on epiphytic bacterial community structure and composition. Analysis of compositions of microbiomes with bias correction (ANCOM-BC) and analysis of variance (ANOVA)-like differential expression (ALDEx2) together identified 312 and 1,362 epiphytes changed in abundance due to fungicide treatments in early summer and early fall, respectively, and over 50% of these epiphytes were negatively impacted by fungicide. The two chlorothalonil-based contact fungicides demonstrated more marked effects than the propiconazole-based systemic fungicide. These results are foundational for exploring and utilizing the full potential of the microbiome and fungicide applications and developing a systems approach to boxwood health and production. IMPORTANCE Agrochemicals are important tools for safeguarding plants from invasive pathogens, insects, mites, and weeds. How they may affect the plant microbiome, a critical component of crop health and production, was poorly understood. Here, we used boxwood, an iconic low-maintenance landscape plant, to characterize shoot epiphytic and endophytic bacterial communities and their responses to contact and systemic fungicides. This study expanded our understanding of the above-ground microbiome in ornamental plants and is foundational for utilizing the full benefits of the microbiome in concert with different fungicide chemistries to improve boxwood health. This study also sets an example for a more thorough evaluation of these and other agrochemicals for their effects on boxwood microbiomes during production and offers an expanded systems approach that could be used with other crops for enhanced integrated pest management.
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Affiliation(s)
- Xiaoping Li
- Hampton Roads Agriculture Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, USA
| | - Hsien Tzer Tseng
- North Carolina Department of Agriculture and Consumer Services, Plant Industry Division, Raleigh, North Carolina, USA
| | - Ginger Hemmings
- North Carolina Department of Agriculture and Consumer Services, Plant Industry Division, Dobson, North Carolina, USA
| | - Olanike Omolehin
- Hampton Roads Agriculture Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, USA
| | - Chad Taylor
- North Carolina Department of Agriculture and Consumer Services, Plant Industry Division, Boone, North Carolina, USA
| | - Amanda Taylor
- North Carolina University Cooperative Extension, Morganton, North Carolina, USA
| | - Ping Kong
- Hampton Roads Agriculture Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, USA
| | - Margery Daughtrey
- Long Island Horticultural Research and Extension Center, Cornell University, Riverhead, New York, USA
| | - Fred Gouker
- USDA-ARS, U.S. National Arboretum, Floral and Nursery Plants Research Unit, Beltsville, Maryland, USA
| | - Chuanxue Hong
- Hampton Roads Agriculture Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, USA
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Chaudhary P, Agri U, Chaudhary A, Kumar A, Kumar G. Endophytes and their potential in biotic stress management and crop production. Front Microbiol 2022; 13:933017. [PMID: 36325026 PMCID: PMC9618965 DOI: 10.3389/fmicb.2022.933017] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/12/2022] [Indexed: 11/21/2022] Open
Abstract
Biotic stress is caused by harmful microbes that prevent plants from growing normally and also having numerous negative effects on agriculture crops globally. Many biotic factors such as bacteria, fungi, virus, weeds, insects, and nematodes are the major constrains of stress that tends to increase the reactive oxygen species that affect the physiological and molecular functioning of plants and also led to the decrease in crop productivity. Bacterial and fungal endophytes are the solution to overcome the tasks faced with conventional farming, and these are environment friendly microbial commodities that colonize in plant tissues without causing any damage. Endophytes play an important role in host fitness, uptake of nutrients, synthesis of phytohormone and diminish the injury triggered by pathogens via antibiosis, production of lytic enzymes, secondary metabolites, and hormone activation. They are also reported to help plants in coping with biotic stress, improving crops and soil health, respectively. Therefore, usage of endophytes as biofertilizers and biocontrol agent have developed an eco-friendly substitute to destructive chemicals for plant development and also in mitigation of biotic stress. Thus, this review highlighted the potential role of endophytes as biofertilizers, biocontrol agent, and in mitigation of biotic stress for maintenance of plant development and soil health for sustainable agriculture.
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Affiliation(s)
- Parul Chaudhary
- Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Upasana Agri
- Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | | | - Ashish Kumar
- Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Govind Kumar
- Indian Council of Agricultural Research (ICAR)-Central Institute for Subtropical Horticulture, Lucknow, India
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Li X, Kong P, Daughtrey M, Kosta K, Schirmer S, Howle M, Likins M, Hong C. Characterization of the Soil Bacterial Community from Selected Boxwood Gardens across the United States. Microorganisms 2022; 10:1514. [PMID: 35893572 PMCID: PMC9330173 DOI: 10.3390/microorganisms10081514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 12/04/2022] Open
Abstract
In a recent study, we observed a rapid decline of the boxwood blight pathogen Calonectria pseudonaviculata (Cps) soil population in all surveyed gardens across the United States, and we speculated that these garden soils might be suppressive to Cps. This study aimed to characterize the soil bacterial community in these boxwood gardens. Soil samples were taken from one garden in California, Illinois, South Carolina, and Virginia and two in New York in early summer and late fall of 2017 and 2018. Soil DNA was extracted and its 16S rRNA amplicons were sequenced using the Nanopore MinION® platform. These garden soils were consistently dominated by Rhizobiales and Burkholderiales, regardless of garden location and sampling time. These two orders contain many species or strains capable of pathogen suppression and plant fitness improvement. Overall, 66 bacterial taxa were identified in this study that are known to have strains with biological control activity (BCA) against plant pathogens. Among the most abundant were Pseudomonas spp. and Bacillus spp., which may have contributed to the Cps decline in these garden soils. This study highlights the importance of soil microorganisms in plant health and provides a new perspective on garden disease management using the soil microbiome.
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Affiliation(s)
- Xiaoping Li
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA; (P.K.); (C.H.)
| | - Ping Kong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA; (P.K.); (C.H.)
| | - Margery Daughtrey
- Long Island Horticultural Research and Extension Center, Cornell University, Riverhead, NY 11901, USA;
| | - Kathleen Kosta
- California Department of Food and Agriculture, Sacramento, CA 95814, USA;
| | - Scott Schirmer
- Bureau of Environmental Programs, Illinois Department of Agriculture, Dekalb, IL 60115, USA;
| | - Matthew Howle
- Department of Plant Industry, Clemson University, Florence, SC 29506, USA;
| | - Michael Likins
- Chesterfield Cooperative Extension, Chesterfield County, VA 23832, USA;
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA; (P.K.); (C.H.)
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cDNA Transcriptome of Arabidopsis Reveals Various Defense Priming Induced by a Broad-Spectrum Biocontrol Agent Burkholderia sp. SSG. Int J Mol Sci 2022; 23:ijms23063151. [PMID: 35328570 PMCID: PMC8954528 DOI: 10.3390/ijms23063151] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/07/2022] [Accepted: 03/12/2022] [Indexed: 02/05/2023] Open
Abstract
Burkholderia sp. SSG is a potent biological control agent. Even though its survival on the leaf surface declined rapidly, SSG provided extended, moderate plant protection from a broad spectrum of pathogens. This study used Arabidopsis Col-0 and its mutants, eds16-1, npr1-1, and pad4-1 as model plants and compared treated plants with non-treated controls to elucidate whether SSG triggers plant defense priming. Only eds16-1 leaves with SSG became purplish, suggesting the involvement of salicylic acid (SA) in SSG-induced priming. cDNA sequencing of Col-0 plants and differential gene expression analysis identified 120 and 119 differentially expressed genes (DEGs) at 6- and 24-h post-treatment (hpt) with SSG, respectively. Most of these DEGs encoded responses to biotic and abiotic stimuli or stresses; four DEGs had more than two isoforms. A total of 23 DEGs were shared at 6 and 24 hpt, showing four regulation patterns. Functional categorization of these shared DEGs, and 44 very significantly upregulated DEGs revealed that SSG triggered various defense priming mechanisms, including responses to phosphate or iron deficiency, modulation of defense-linked SA, jasmonic acid, ethylene, and abscisic acid pathways, defense-related gene regulation, and chromatin modification. These data support that SSG is an induced systemic resistance (ISR) trigger conferring plant protection upon pathogen encounter.
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Wang Y, Huang W, Li Y, Yu F, Penttinen P. Isolation, characterization, and evaluation of a high-siderophore-yielding bacterium from heavy metal-contaminated soil. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:3888-3899. [PMID: 34402014 DOI: 10.1007/s11356-021-15996-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
Heavy metal-resistant siderophore-producing bacteria (SPB) with plant growth-promoting traits can assist in phytoremediation of heavy metal-contaminated soil. We isolated siderophore-producing bacteria from Pb and Zn mine soil in Shangyu, Zhejiang, China. The isolate with the highest siderophore production, strain SX9, was identified as Burkholderia sp. Burkholderia sp. SX9 produced catecholate-type siderophore, with the highest production at a pH range of 6.0 to 8.0, a temperature range of 20 to 30 °C and NaCl concentration below 2%. Siderophore production was highest without Fe3+ and became gradually lower with increasing Fe3+ concentration. Minimal inhibitory concentrations (MIC) of Pb2+, Zn2+, Cu2+, and Cd2+ were 4000, 22000, 5000, and 2000 μmol L-1, respectively. The strain had a strong metal solubilization ability: the contents of Cu2+, Zn2+, and Cd2+ in the supernatant were 47.4%, 133.0%, and 35.4% higher, respectively, in strain SX9-inoculated cultures than in the not inoculated controls. The siderophore produced by strain SX9 could combine with Fe3+, Zn2+, and Cd2+ with good effectiveness. The plant growth-promoting traits of the strain included indole acetic acid (IAA) production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, and phosphate solubilization capability. Compared to the uninoculated growth medium and SX9 culture supernatant, the germination rate of Lolium perenne seeds was higher when inoculated with strain SX9 culture. In the experiment of seed germination, adding bacterial culture or supernatant could alleviate the toxicity of heavy metals to L. perenne seed germination. Under Cu2+ and Zn2+ stress, strain SX9 promoted the germination rate. Taken together, Burkholderia sp. SX9 had properties beneficial in the microbial enhancement of phytoremediation of soil contaminated with heavy metals.
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Affiliation(s)
- Yajun Wang
- Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang Agriculture and Forestry University, Lin'an, Zhejiang, 311300, People's Republic of China
| | - Wei Huang
- Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang Agriculture and Forestry University, Lin'an, Zhejiang, 311300, People's Republic of China
| | - Yaqian Li
- Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang Agriculture and Forestry University, Lin'an, Zhejiang, 311300, People's Republic of China
| | - Fangbo Yu
- Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang Agriculture and Forestry University, Lin'an, Zhejiang, 311300, People's Republic of China.
| | - Petri Penttinen
- Department of Microbiology, College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China.
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Kong P, Sharifi M, Bordas A, Hong C. Differential Tolerance to Calonectria pseudonaviculata of English Boxwood Plants Associated with the Complexity of Culturable Fungal and Bacterial Endophyte Communities. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112244. [PMID: 34834607 PMCID: PMC8619141 DOI: 10.3390/plants10112244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 05/22/2023]
Abstract
Isolated boxwood endophytes have been demonstrated to effectively protect boxwood plants from infection by Calonectria pseudonaviculata (Cps). However, the roles of endophytes as communities in plant defense are not clear. Here, we demonstrated differential tolerance to Cps of English boxwood (Buxus sempervirens 'Suffruticosa'), an iconic landscape plant and generally regarded as highly susceptible, and its link to endophyte complexity. Fifteen boxwood twig samples were collected in triplicates from three historic gardens-Colonial Williamsburg, George Washington's Mount Vernon and River Farm, and Virginia Tech's research farm in Virginia Beach in the summer and fall of 2019. A portion of individual samples was inoculated with Cps under controlled conditions. Significant differences in disease severity were observed among samples but not between the two seasons. Examining the endophyte cultures of the summer samples revealed that bacterial and fungal abundance was negatively and positively correlated with the disease severity. Nanopore metagenomics analysis on genomic DNA of the tolerant and susceptible group representatives confirmed the associations. Specifically, tolerant English boxwood plants had an endophyte community dominated by Bacilli and Betaproteobacteria, while susceptible ones had a distinct endophyte community dominated by Gammaproteobacteria, Actinobacteria, and diverse fungi. These findings may lead to boxwood health management innovations-devising and utilizing cultural practices to manipulate and increase the abundance and performance of beneficial endophytes for enhanced boxwood resistance to Cps.
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Affiliation(s)
- Ping Kong
- Virginia Tech, Hampton Roads Agricultural Research and Extension Center, 1444 Diamond Springs Road, Virginia Beach, VA 23455, USA;
- Correspondence: ; Tel.: +1-757-363-3941
| | - Melissa Sharifi
- The Colonial Williamsburg Foundation, P.O. Box 1776, Williamsburg, VA 23185, USA;
| | - Adria Bordas
- Virginia Cooperative Extension, Fairfax Co., 12011 Government Center Parkway, Fairfax, VA 22035, USA;
| | - Chuanxue Hong
- Virginia Tech, Hampton Roads Agricultural Research and Extension Center, 1444 Diamond Springs Road, Virginia Beach, VA 23455, USA;
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Hwang HH, Chien PR, Huang FC, Hung SH, Kuo CH, Deng WL, Chiang EPI, Huang CC. A Plant Endophytic Bacterium, Burkholderia seminalis Strain 869T2, Promotes Plant Growth in Arabidopsis, Pak Choi, Chinese Amaranth, Lettuces, and Other Vegetables. Microorganisms 2021; 9:microorganisms9081703. [PMID: 34442782 PMCID: PMC8401003 DOI: 10.3390/microorganisms9081703] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/09/2021] [Accepted: 08/09/2021] [Indexed: 12/03/2022] Open
Abstract
Plant endophytic bacteria live inside host plants, can be isolated from surface-sterilized plant tissues, and are non-pathogenic. These bacteria can assist host plants in obtaining more nutrients and can improve plant growth via multiple mechanisms. Certain Gram-negative Burkholderia species, including rhizobacteria, bioremediators, and biocontrol strains, have been recognized for their plant-growth-promoting abilities, while other isolates have been identified as opportunistic plant or human pathogens. In this study, we observed the auxin production, siderophore synthesis, and phosphate solubilization abilities of B. seminalis strain 869T2. Our results demonstrated that strain 869T2 promoted growth in Arabidopsis, ching chiang pak choi, pak choi, loose-leaf lettuce, romaine lettuce, red leaf lettuce, and Chinese amaranth. Leafy vegetables inoculated with strain 869T2 were larger, heavier, and had more and larger leaves and longer and heavier roots than mock-inoculated plants. Furthermore, inoculations of strain 869T2 into hot pepper caused increased flower and fruit production, and a higher percentage of fruits turned red. Inoculation of strain 869T2 into okra plants resulted in earlier flowering and increased fruit weight. In conclusion, the plant endophytic bacterium Burkholderia seminalis 869T2 exerted positive effects on growth and production in several plant species.
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Affiliation(s)
- Hau-Hsuan Hwang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (P.-R.C.); (F.-C.H.); (S.-H.H.)
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan;
- Correspondence: (H.-H.H.); (C.-C.H.); Tel.: +886-4-2284-0416-412 (H.-H.H.); +886-4-2284-0416-402 (C.-C.H.); Fax: +886-4-2287-4740 (H.-H.H. & C.-C.H.)
| | - Pei-Ru Chien
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (P.-R.C.); (F.-C.H.); (S.-H.H.)
| | - Fan-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (P.-R.C.); (F.-C.H.); (S.-H.H.)
| | - Shih-Hsun Hung
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (P.-R.C.); (F.-C.H.); (S.-H.H.)
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan;
| | - Wen-Ling Deng
- Department of Plant Pathology, National Chung Hsing University, Taichung 402, Taiwan;
| | - En-Pei Isabel Chiang
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan;
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
| | - Chieh-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (P.-R.C.); (F.-C.H.); (S.-H.H.)
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan;
- Correspondence: (H.-H.H.); (C.-C.H.); Tel.: +886-4-2284-0416-412 (H.-H.H.); +886-4-2284-0416-402 (C.-C.H.); Fax: +886-4-2287-4740 (H.-H.H. & C.-C.H.)
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