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Christian N, Perlin MH. Plant-endophyte communication: Scaling from molecular mechanisms to ecological outcomes. Mycologia 2024; 116:227-250. [PMID: 38380970 DOI: 10.1080/00275514.2023.2299658] [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: 05/10/2023] [Accepted: 12/22/2023] [Indexed: 02/22/2024]
Abstract
Diverse communities of fungal endophytes reside in plant tissues, where they affect and are affected by plant physiology and ecology. For these intimate interactions to form and persist, endophytes and their host plants engage in intricate systems of communication. The conversation between fungal endophytes and plant hosts ultimately dictates endophyte community composition and function and has cascading effects on plant health and plant interactions. In this review, we synthesize our current knowledge on the mechanisms and strategies of communication used by endophytic fungi and their plant hosts. We discuss the molecular mechanisms of communication that lead to organ specificity of endophytic communities and distinguish endophytes, pathogens, and saprotrophs. We conclude by offering emerging perspectives on the relevance of plant-endophyte communication to microbial community ecology and plant health and function.
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Affiliation(s)
- Natalie Christian
- Department of Biology, University of Louisville, Louisville, Kentucky 40292
| | - Michael H Perlin
- Department of Biology, University of Louisville, Louisville, Kentucky 40292
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Rering CC, Rudolph AB, Li QB, Read QD, Muñoz PR, Ternest JJ, Hunter CT. A quantitative survey of the blueberry (Vaccinium spp.) culturable nectar microbiome: variation between cultivars, locations, and farm management approaches. FEMS Microbiol Ecol 2024; 100:fiae020. [PMID: 38366934 PMCID: PMC10903978 DOI: 10.1093/femsec/fiae020] [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: 08/01/2023] [Revised: 01/25/2024] [Accepted: 02/15/2024] [Indexed: 02/19/2024] Open
Abstract
Microbes in floral nectar can impact both their host plants and floral visitors, yet little is known about the nectar microbiome of most pollinator-dependent crops. In this study, we examined the abundance and composition of the fungi and bacteria inhabiting Vaccinium spp. nectar, as well as nectar volume and sugar concentrations. We compared wild V. myrsinites with two field-grown V. corymbosum cultivars collected from two organic and two conventional farms. Differences in nectar traits and microbiomes were identified between V. corymbosum cultivars but not Vaccinium species. The microbiome of cultivated plants also varied greatly between farms, whereas management regime had only subtle effects, with higher fungal populations detected under organic management. Nectars were hexose-dominant, and high cell densities were correlated with reduced nectar sugar concentrations. Bacteria were more common than fungi in blueberry nectar, although both were frequently detected and co-occurred more often than would be predicted by chance. "Cosmopolitan" blueberry nectar microbes that were isolated in all plants, including Rosenbergiella sp. and Symmetrospora symmetrica, were identified. This study provides the first systematic report of the blueberry nectar microbiome, which may have important implications for pollinator and crop health.
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Affiliation(s)
- Caitlin C Rering
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
| | - Arthur B Rudolph
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
| | - Qin-Bao Li
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
| | - Quentin D Read
- Agricultural Research Service, Southeast Area, United States Department of Agriculture, 840 Oval Drive, Raleigh, NC 27606, United States
| | - Patricio R Muñoz
- Horticultural Sciences Department, University of Florida, 2550 Hull Rd, Gainesville, FL 32611, United States
| | - John J Ternest
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Dr, Gainesville, FL 32611, United States
| | - Charles T Hunter
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
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Rering CC, Lanier AM, Peres NA. Blueberry floral probiotics: nectar microbes inhibit the growth of Colletotrichum pathogens. J Appl Microbiol 2023; 134:lxad300. [PMID: 38061796 DOI: 10.1093/jambio/lxad300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/24/2023] [Accepted: 12/05/2023] [Indexed: 12/29/2023]
Abstract
AIMS To identify whether microorganisms isolated from blueberry flowers can inhibit the growth of Colletotrichum, an opportunistic plant pathogen that infects flowers and threatens yields, and to assess the impacts of floral microbes and Colletotrichum pathogens on artificial nectar sugars and honey bee consumption. METHODS AND RESULTS The growth inhibition of Colletotrichum (Colletotrichum acutatum, Colletotrichum fioriniae, and Colletotrichum gloeosporioides) was screened using both artificial nectar co-culture and dual culture plate assays. All candidate nectar microbes were screened for antagonism against a single C. acutatum isolate. Then, the top four candidate nectar microbes showing the strongest inhibition of C. acutatum (Neokomagataea thailandica, Neokomagataea tanensis, Metschnikowia rancensis, and Symmetrospora symmetrica) were evaluated for antagonism against three additional C. acutatum isolates, and single isolates of both C. fioriniae and C. gloeosporioides. In artificial nectar assays, single and three-species cultures inhibited the growth of two of four C. acutatum isolates by ca. 60%, but growth of other Colletotrichum species was not affected. In dual culture plate assays, inhibition was observed for all Colletotrichum species for at least three of four selected microbial antagonists (13%‒53%). Neither honey bee consumption of nectar nor nectar sugar concentrations were affected by any microbe or pathogen tested. CONCLUSIONS Selected floral microbes inhibited growth of all Colletotrichum species in vitro, although the degree of inhibition was specific to the assay and pathogen examined. In all microbial treatments, nectar sugars were preserved, and honey bee preference was not affected.
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Affiliation(s)
- Caitlin C Rering
- Chemistry Research Unit, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL 32608, United States
| | - Alexia M Lanier
- Chemistry Research Unit, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL 32608, United States
| | - Natalia A Peres
- Department of Horticulture, Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598, United States
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Francis JS, Mueller TG, Vannette RL. Intraspecific variation in realized dispersal probability and host quality shape nectar microbiomes. THE NEW PHYTOLOGIST 2023; 240:1233-1245. [PMID: 37614102 DOI: 10.1111/nph.19195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/16/2023] [Indexed: 08/25/2023]
Abstract
Epiphytic microbes frequently affect plant phenotype and fitness, but their effects depend on microbe abundance and community composition. Filtering by plant traits and deterministic dispersal-mediated processes can affect microbiome assembly, yet their relative contribution to predictable variation in microbiome is poorly understood. We compared the effects of host-plant filtering and dispersal on nectar microbiome presence, abundance, and composition. We inoculated representative bacteria and yeast into 30 plants across four phenotypically distinct cultivars of Epilobium canum. We compared the growth of inoculated communities to openly visited flowers from a subset of the same plants. There was clear evidence of host selection when we inoculated flowers with synthetic communities. However, plants with the highest microbial densities when inoculated did not have the highest microbial densities when openly visited. Instead, plants predictably varied in the presence of bacteria, which was correlated with pollen receipt and floral traits, suggesting a role for deterministic dispersal. These findings suggest that host filtering could drive plant microbiome assembly in tissues where species pools are large and dispersal is high. However, deterministic differences in microbial dispersal to hosts may be equally or more important when microbes rely on an animal vector, dispersal is low, or arrival order is important.
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Affiliation(s)
- Jacob S Francis
- Department of Entomology and Nematology, University of California Davis, Davis, CA, 95616, USA
| | - Tobias G Mueller
- Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California Davis, Davis, CA, 95616, USA
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Rutkowski D, Weston M, Vannette RL. Bees just wanna have fungi: a review of bee associations with nonpathogenic fungi. FEMS Microbiol Ecol 2023; 99:fiad077. [PMID: 37422442 PMCID: PMC10370288 DOI: 10.1093/femsec/fiad077] [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: 04/20/2023] [Revised: 06/15/2023] [Accepted: 07/06/2023] [Indexed: 07/10/2023] Open
Abstract
Bee-fungus associations are common, and while most studies focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi that can influence bee behavior and health. Here, we review nonpathogenic fungal taxa associated with different bee species and bee-related habitats. We synthesize results of studies examining fungal effects on bee behavior, development, survival, and fitness. We find that fungal communities differ across habitats, with some groups restricted mostly to flowers (Metschnikowia), while others are present almost exclusively in stored provisions (Zygosaccharomyces). Starmerella yeasts are found in multiple habitats in association with many bee species. Bee species differ widely in the abundance and identity of fungi hosted. Functional studies suggest that yeasts affect bee foraging, development, and pathogen interactions, though few bee and fungal taxa have been examined in this context. Rarely, fungi are obligately beneficial symbionts of bees, whereas most are facultative bee associates with unknown or ecologically contextual effects. Fungicides can reduce fungal abundance and alter fungal communities associated with bees, potentially disrupting bee-fungi associations. We recommend that future study focus on fungi associated with non-honeybee species and examine multiple bee life stages to document fungal composition, abundance, and mechanistic effects on bees.
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Affiliation(s)
- Danielle Rutkowski
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Makena Weston
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Rachel L Vannette
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
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Burgess EC, Schaeffer RN. The Floral Microbiome and Its Management in Agroecosystems: A Perspective. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:9819-9825. [PMID: 35917340 DOI: 10.1021/acs.jafc.2c02037] [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] [Indexed: 06/15/2023]
Abstract
Disease management is critical to ensuring healthy crop yields and is often targeted at flowers because of their susceptibility to pathogens and direct link to reproduction. Many disease management strategies are unsustainable however because of the potential for pathogens to evolve resistance, or nontarget effects on beneficial insects. Manipulating the floral microbiome holds some promise as a sustainable alternative to chemical means of disease control. In this perspective, we discuss the current state of research concerning floral microbiome assembly and management in agroecosystems as well as future directions aimed at improving the sustainability of disease control and insect-mediated ecosystem services.
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Affiliation(s)
- Emily C Burgess
- Department of Biology, Utah State University, Logan, Utah 84322, United States
| | - Robert N Schaeffer
- Department of Biology, Utah State University, Logan, Utah 84322, United States
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Bellamy S, Shaw M, Xu X. Field application of Bacillus subtilis and Aureobasidium pullulans to reduce Monilinia laxa post-harvest rot on cherry. EUROPEAN JOURNAL OF PLANT PATHOLOGY 2022; 163:761-766. [PMID: 35756540 PMCID: PMC9213261 DOI: 10.1007/s10658-022-02508-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED Brown rot caused by Monilinia spp. is one of the most important diseases in stone fruits worldwide. Latent infections of fruit by the pathogen often manifest once the fruit is ripe, leading to post-harvest rots. Two microbial strains (Bacillus subtilis -B91 and Aureobasidium pullulans - Y126) have shown antagonistic properties against M. laxa in previous studies. This study assessed the reduction in post-harvest rot of cherry by M. laxa when the two biocontrol (BCAs) strains were applied pre-harvest under field conditions to fruit artificially inoculated with M. laxa. The experiment was carried out for two consecutive years in cherry orchards in Kent. When applied pre-harvest, both strains (B91 and Y126) reduced the incidence of post-harvest rots by 30% - 60%. This promising result helps towards the commercialisation of the two strains, which would reduce reliance on fungicides in commercial cherry production. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10658-022-02508-8.
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Affiliation(s)
- Sophia Bellamy
- Pest & Pathogen Ecology, NIAB, West Malling, KY ME19 6BJ UK
- School of Agriculture, Policy and Development, University of Reading, Reading, Berkshire UK
| | - Michael Shaw
- School of Agriculture, Policy and Development, University of Reading, Reading, Berkshire UK
| | - Xiangming Xu
- Pest & Pathogen Ecology, NIAB, West Malling, KY ME19 6BJ UK
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