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Castro-Severyn J, Fortt J, Sierralta M, Alegria P, Donoso G, Choque A, Avellaneda AM, Pardo-Esté C, Saavedra CP, Stoll A, Remonsellez F. Rhizospheric bacteria from the Atacama Desert hyper-arid core: cultured community dynamics and plant growth promotion. Microbiol Spectr 2024; 12:e0005624. [PMID: 38687070 PMCID: PMC11237387 DOI: 10.1128/spectrum.00056-24] [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: 01/08/2024] [Accepted: 04/01/2024] [Indexed: 05/02/2024] Open
Abstract
The Atacama Desert is the oldest and driest desert on Earth, encompassing great temperature variations, high ultraviolet radiation, drought, and high salinity, making it ideal for studying the limits of life and resistance strategies. It is also known for harboring a great biodiversity of adapted life forms. While desertification is increasing as a result of climate change and human activities, it is necessary to optimize soil and water usage, where stress-resistant crops are possible solutions. As many studies have revealed the great impact of the rhizobiome on plant growth efficiency and resistance to abiotic stress, we set up to explore the rhizospheric soils of Suaeda foliosa and Distichlis spicata desert plants. By culturing these soils and using 16S rRNA amplicon sequencing, we address community taxonomy composition dynamics, stability through time, and the ability to promote lettuce plant growth. The rhizospheric soil communities were dominated by the families Pseudomonadaceae, Bacillaceae, and Planococcaceae for S. foliosa and Porphyromonadaceae and Haloferacaceae for D. spicata. Nonetheless, the cultures were completely dominated by the Enterobacteriaceae family (up to 98%). Effectively, lettuce plants supplemented with the cultures showed greater size and biomass accumulation. We identified 12 candidates that could be responsible for these outcomes, of which 5 (Enterococcus, Pseudomonas, Klebsiella, Paenisporosarcina, and Ammoniphilus) were part of the built co-occurrence network. We aim to contribute to the efforts to characterize the microbial communities as key for the plant's survival in extreme environments and as a possible source of consortia with plant growth promotion traits aimed at agricultural applications.IMPORTANCEThe current scenario of climate change and desertification represents a series of incoming challenges for all living organisms. As the human population grows rapidly, so does the rising demand for food and natural resources; thus, it is necessary to make agriculture more efficient by optimizing soil and water usage, thus ensuring future food supplies. Particularly, the Atacama Desert (northern Chile) is considered the most arid place on Earth as a consequence of geological and climatic characteristics, such as the naturally low precipitation patterns and high temperatures, which makes it an ideal place to carry out research that seeks to aid agriculture in future conditions that are predicted to resemble these scenarios. Our main interest lies in utilizing microorganism consortia from plants thriving under extreme conditions, aiming to promote plant growth, improve crops, and render "unsuitable" soils farmable.
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Affiliation(s)
- Juan Castro-Severyn
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Tecnológica del Agua y Sustentabilidad en el Desierto-CEITSAZA, Universidad Católica del Norte, Antofagasta, Chile
| | - Jonathan Fortt
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Mariela Sierralta
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Paola Alegria
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Gabriel Donoso
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Alessandra Choque
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Andrea M. Avellaneda
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Tecnológica del Agua y Sustentabilidad en el Desierto-CEITSAZA, Universidad Católica del Norte, Antofagasta, Chile
| | - Coral Pardo-Esté
- Laboratorio de Ecología Molecular y Microbiología Aplicada, Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte, Antofagasta, Chile
| | - Claudia P. Saavedra
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Alexandra Stoll
- Laboratorio de Microbiología Aplicada, Centro de Estudios Avanzados en Zonas Áridas CEAZA, La Serena, Chile
- Instituto de Investigación Multidisciplinar en Ciencia y Tecnología, Universidad de la Serena, La Serena, Chile
| | - Francisco Remonsellez
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química y de Medio Ambiente, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Tecnológica del Agua y Sustentabilidad en el Desierto-CEITSAZA, Universidad Católica del Norte, Antofagasta, Chile
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Wang W, Hu C, Chang Y, Wang L, Bi Q, Lu X, Zheng Z, Zheng X, Wu D, Niu B. Differentiated responses of the phyllosphere bacterial community of the yellowhorn tree to precipitation and temperature regimes across Northern China. FRONTIERS IN PLANT SCIENCE 2023; 14:1265362. [PMID: 37954985 PMCID: PMC10634255 DOI: 10.3389/fpls.2023.1265362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 10/10/2023] [Indexed: 11/14/2023]
Abstract
Introduction As an ephemeral and oligotrophic environment, the phyllosphere harbors many highly diverse microorganisms. Importantly, it is known that their colonization of plant leaf surfaces is considerably influenced by a few abiotic factors related to climatic conditions. Yet how the dynamics of phyllosphere bacterial community assembly are shaped by detailed climatological elements, such as various bioclimatic variables, remains poorly understood. Methods Using high-throughput 16S rRNA gene amplicon sequencing technology, we analyzed the bacterial communities inhabiting the leaf surfaces of an oilseed tree, yellowhorn (Xanthoceras sorbifolium), grown at four sites (Yinchuan, Otogqianqi, Tongliao, and Zhangwu) whose climatic status differs in northern China. Results and Discussion We found that the yellowhorn phyllosphere's bacterial community was generally dominated by four phyla: Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Nevertheless, bacterial community composition differed significantly among the four sampled site regions, indicating the possible impact of climatological factors upon the phyllosphere microbiome. Interestingly, we also noted that the α-diversities of phyllosphere microbiota showed strong positive or negative correlation with 13 bioclimatic factors (including 7 precipitation factors and 6 temperature factors). Furthermore, the relative abundances of 55 amplicon sequence variants (ASVs), including three ASVs representing two keystone taxa (the genera Curtobacterium and Streptomyces), exhibited significant yet contrary responses to the precipitation and temperature climatic variables. That pattern was consistent with all ASVs' trends of possessing opposite correlations to those two parameter classes. In addition, the total number of links and nodes, which conveys community network complexity, increased with rising values of most temperature variables. Besides that, remarkably positive relevance was found between average clustering coefficient and most precipitation variables. Altogether, these results suggest the yellowhorn phyllosphere bacterial community is capable of responding to variation in rainfall and temperature regimes in distinctive ways.
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Affiliation(s)
- Weixiong Wang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
- The Center for Basic Forestry Research, College of Forestry, Northeast Forestry University, Harbin, China
- College of Life Science, Northeast Forestry University, Harbin, China
| | - Congcong Hu
- Department of Mathematics, Shanghai Normal University, Shanghai, China
| | - Yu Chang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
- College of Life Science, Northeast Forestry University, Harbin, China
| | - Libing Wang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Quanxin Bi
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Xin Lu
- Chifeng Research Institute of Forestry Science, Chifeng, China
- National Forestry and Grassland Shiny-Leaved Yellowhorn Engineering and Technology Research Center, Chifeng, China
| | - Zhimin Zheng
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
- The Center for Basic Forestry Research, College of Forestry, Northeast Forestry University, Harbin, China
| | - Xiaoqi Zheng
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Di Wu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
- The Center for Basic Forestry Research, College of Forestry, Northeast Forestry University, Harbin, China
- College of Life Science, Northeast Forestry University, Harbin, China
| | - Ben Niu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
- The Center for Basic Forestry Research, College of Forestry, Northeast Forestry University, Harbin, China
- College of Life Science, Northeast Forestry University, Harbin, China
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Zhang M, Peng C, Sun W, Dong R, Hao J. Effects of Variety, Plant Location, and Season on the Phyllosphere Bacterial Community Structure of Alfalfa (Medicago sativa L.). Microorganisms 2022; 10:microorganisms10102023. [PMID: 36296299 PMCID: PMC9610643 DOI: 10.3390/microorganisms10102023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 10/05/2022] [Accepted: 10/11/2022] [Indexed: 11/16/2022] Open
Abstract
Plant phyllosphere bacteria are vital for plant health and productivity and are affected by both abiotic and biotic factors. In this study, we surveyed the structure of the phyllosphere bacterial community associated with alfalfa. For two varieties of alfalfa, forty-eight samples of phyllosphere communities were collected at two locations over four seasons in 2020. Proteobacteria and actinobacteria were associated with the dominating phylum in the bacterial communities of the alfalfa phyllosphere. Sphingomonas was the most abundant genus-level bacteria, followed by Methylobacterium, Burkholderia-Caballeronia-Paraburkholderia, and Pseudomonas. Sampling time had a greater affect than site and variety on alfalfa surface microorganisms. The variation in phyllosphere bacterial community assembly was mostly explained by the season–site interaction (43%), season–variety interaction (35%), and season (28%). Variety, site–variety interaction, and season–site–variety interactions did not have a meaningful effect on phyllosphere bacterial diversity and community structure. The bacterial community in the phyllosphere of alfalfa showed seasonal changes over time. The environmental factors that contributed most to the phyllosphere bacterial community of alfalfa were temperature and sunshine duration, which were significantly positively correlated with most of the dominant bacterial genera in the alfalfa phyllosphere.
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Xing L, Yang J, Jia Y, Hu X, Liu Y, Xu H, Yin H, Li J, Yi Z. Effects of ecological environment and host genotype on the phyllosphere bacterial communities of cigar tobacco ( Nicotiana tabacum L.). Ecol Evol 2021; 11:10892-10903. [PMID: 34429888 PMCID: PMC8366869 DOI: 10.1002/ece3.7861] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/05/2021] [Accepted: 06/10/2021] [Indexed: 12/03/2022] Open
Abstract
Microorganisms of plant phyllosphere play an important role in plant health and productivity and are influenced by abiotic and biotic factors. In this study, we investigated the phyllosphere bacterial communities of three cigar tobacco varieties cultivated in Guangcun (GC) and Wuzhishan (WZS), Hainan, China. Metagenomic DNA was extracted from tobacco leaf samples and sequenced by 16S rDNA amplicon sequencing. Our results showed that bacterial communities of cigar tobacco phyllosphere in GC exhibited remarkably higher alpha diversity than that in WZS. There was slight effect of tobacco genotype variations on the alpha diversity in both cultivation sites, and beta diversity and structure of bacterial community were not influenced significantly by the cultivation sites and tobacco varieties. Statistical analyses of species diversity unraveled that the dominant species in bacterial communities of cigar tobacco phyllosphere among all these samples were phylogenetically affiliated to Proteobacteria and Cyanobacteria. At the genus level, the most abundant microorganism was Limnobacter, followed by Brevundimonas, unidentified_Cyanobacteria, and Pseudomonas. Additionally, environmental conditions except for humidity were negatively correlated with the relative abundance of bacterial genera. Further analyses revealed that influence of site-specific factors on tobacco bacterial community was relatively higher than genotype-specific factors. In short, this study may contribute to the knowledge base of practical applications of bacterial inoculants for tobacco leaf production.
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Affiliation(s)
- Lei Xing
- College of AgronomyHunan Agricultural UniversityChangshaChina
- Greatwall Cigar FactoryChina Tobacco Sichuan Industrial Co., LtdShifangChina
| | - Jianlei Yang
- School of Minerals Processing and BioengineeringCentral South UniversityChangshaChina
| | - Yuhong Jia
- Greatwall Cigar FactoryChina Tobacco Sichuan Industrial Co., LtdShifangChina
| | - Xi Hu
- Greatwall Cigar FactoryChina Tobacco Sichuan Industrial Co., LtdShifangChina
| | - Yi Liu
- Greatwall Cigar FactoryChina Tobacco Sichuan Industrial Co., LtdShifangChina
| | - Heng Xu
- Greatwall Cigar FactoryChina Tobacco Sichuan Industrial Co., LtdShifangChina
| | - Huaqun Yin
- School of Minerals Processing and BioengineeringCentral South UniversityChangshaChina
| | - Juan Li
- College of AgronomyHunan Agricultural UniversityChangshaChina
| | - Zhenxie Yi
- College of AgronomyHunan Agricultural UniversityChangshaChina
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Al Ashhab A, Meshner S, Alexander-Shani R, Dimerets H, Brandwein M, Bar-Lavan Y, Winters G. Temporal and Spatial Changes in Phyllosphere Microbiome of Acacia Trees Growing in Arid Environments. Front Microbiol 2021; 12:656269. [PMID: 34322096 PMCID: PMC8312645 DOI: 10.3389/fmicb.2021.656269] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/31/2021] [Indexed: 02/01/2023] Open
Abstract
Background: The evolutionary relationships between plants and their microbiomes are of high importance to the survival of plants in general and even more in extreme conditions. Changes in the plant's microbiome can affect plant development, growth, fitness, and health. Along the arid Arava, southern Israel, acacia trees (Acacia raddiana and Acacia tortilis) are considered keystone species. In this study, we investigated the ecological effects of plant species, microclimate, phenology, and seasonality on the epiphytic and endophytic microbiome of acacia trees. One hundred thirty-nine leaf samples were collected throughout the sampling year and were assessed using 16S rDNA gene amplified with five different primers (targeting different gene regions) and sequenced (150 bp paired-end) on an Illumina MiSeq sequencing platform. Results: Epiphytic bacterial diversity indices (Shannon-Wiener, Chao1, Simpson, and observed number of operational taxonomic units) were found to be nearly double compared to endophyte counterparts. Epiphyte and endophyte communities were significantly different from each other in terms of the composition of the microbial associations. Interestingly, the epiphytic bacterial diversity was similar in the two acacia species, but the canopy sides and sample months exhibited different diversity, whereas the endophytic bacterial communities were different in the two acacia species but similar throughout the year. Abiotic factors, such as air temperature and precipitation, were shown to significantly affect both epiphyte and endophytes communities. Bacterial community compositions showed that Firmicutes dominate A. raddiana, and Proteobacteria dominate A. tortilis; these bacterial communities consisted of only a small number of bacterial families, mainly Bacillaceae and Comamonadaceae in the endophyte for A. raddiana and A. tortilis, respectively, and Geodematophilaceae and Micrococcaceae for epiphyte bacterial communities, respectively. Interestingly, ~60% of the obtained bacterial classifications were unclassified below family level (i.e., "new"). Conclusions: These results shed light on the unique desert phyllosphere microbiome highlighting the importance of multiple genotypic and abiotic factors in shaping the epiphytic and endophytic microbial communities. This study also shows that only a few bacterial families dominate both epiphyte and endophyte communities, highlighting the importance of climate change (precipitation, air temperature, and humidity) in affecting arid land ecosystems where acacia trees are considered keystone species.
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Affiliation(s)
- Ashraf Al Ashhab
- Dead Sea and Arava Science Center, Masada, Israel.,Ben-Gurion University of the Negev, Eilat Campus, Be'er Sheva, Israel
| | | | | | | | - Michael Brandwein
- Dead Sea and Arava Science Center, Masada, Israel.,Biofilm Research Laboratory, Faculty of Dental Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Gidon Winters
- Dead Sea and Arava Science Center, Masada, Israel.,Ben-Gurion University of the Negev, Eilat Campus, Be'er Sheva, Israel
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Saline and Arid Soils: Impact on Bacteria, Plants, and their Interaction. BIOLOGY 2020; 9:biology9060116. [PMID: 32498442 PMCID: PMC7344409 DOI: 10.3390/biology9060116] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/26/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022]
Abstract
Salinity and drought are the most important abiotic stresses hampering crop growth and yield. It has been estimated that arid areas cover between 41% and 45% of the total Earth area worldwide. At the same time, the world’s population is going to soon reach 9 billion and the survival of this huge amount of people is dependent on agricultural products. Plants growing in saline/arid soil shows low germination rate, short roots, reduced shoot biomass, and serious impairment of photosynthetic efficiency, thus leading to a substantial loss of crop productivity, resulting in significant economic damage. However, plants should not be considered as single entities, but as a superorganism, or a holobiont, resulting from the intimate interactions occurring between the plant and the associated microbiota. Consequently, it is very complex to define how the plant responds to stress on the basis of the interaction with its associated plant growth-promoting bacteria (PGPB). This review provides an overview of the physiological mechanisms involved in plant survival in arid and saline soils and aims at describing the interactions occurring between plants and its bacteriome in such perturbed environments. The potential of PGPB in supporting plant survival and fitness in these environmental conditions has been discussed.
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Vokou D, Genitsaris S, Karamanoli K, Vareli K, Zachari M, Voggoli D, Monokrousos N, Halley JM, Sainis I. Metagenomic Characterization Reveals Pronounced Seasonality in the Diversity and Structure of the Phyllosphere Bacterial Community in a Mediterranean Ecosystem. Microorganisms 2019; 7:microorganisms7110518. [PMID: 31683878 PMCID: PMC6920919 DOI: 10.3390/microorganisms7110518] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/20/2019] [Accepted: 10/29/2019] [Indexed: 01/29/2023] Open
Abstract
We explore how the phyllosphere microbial community responds to a very seasonal environment such as the Mediterranean. For this, we studied the epiphytic bacterial community of a Mediterranean ecosystem in summer and winter, expecting to detect seasonal differences at their maximum. With high-throughput sequencing (HTS), we detected the operational taxonomic units (OTUs) present in the phyllosphere and also in the surrounding air. The epiphytic community is approximately five orders of magnitude denser than the airborne one and is made almost exclusively by habitat specialists. The two communities differ considerably but Proteobacteria and Actinobacteria are dominant in both. Of the five most abundant phyllosphere OTUs, two were closely related to Sphingomonas strains, one to Methylobacterium and the other two to Rhizobiales and Burkholderiales. We found the epiphytic community to become much richer, more distinct, even and diverse, denser and more connected in summer. In contrast, there was no difference in the level of bacterial colonization of the phyllosphere between the two seasons, although there were seasonal differences for individual taxonomic groups: Firmicutes, Gemmatimonadetes and Chlroroflexi had a higher participation in summer, whereas the major Proteobacteria classes presented reverse patterns, with Betaproteobacteria increasing in summer at the expense of the prominent Alphaproteobacteria.
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Affiliation(s)
- Despoina Vokou
- Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
| | - Savvas Genitsaris
- School of Economics, Business Administration and Legal Studies, International Hellenic University, 57001 Thermi, Greece.
| | - Katerina Karamanoli
- School of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
| | - Katerina Vareli
- Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece.
| | - Marina Zachari
- Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece.
| | - Despoina Voggoli
- Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece.
| | - Nikolaos Monokrousos
- Department of Soil Science of Athens, Hellenic Agricultural Organization-Demeter, Institute of Soil and Water Resources, 14123 Lykovrisi, Greece.
| | - John Maxwell Halley
- Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece.
| | - Ioannis Sainis
- Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece.
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Valverde A, González-Tirante M, Medina-Sierra M, Rivas R, Santa-Regina I, Igual JM. Culturable bacterial diversity from the chestnut ( Castanea sativa Mill.) phyllosphere and antagonism against the fungi causing the chestnut blight and ink diseases. AIMS Microbiol 2017; 3:293-314. [PMID: 31294162 PMCID: PMC6605015 DOI: 10.3934/microbiol.2017.2.293] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/21/2017] [Indexed: 11/18/2022] Open
Abstract
The phyllosphere supports a large and complex bacterial community that varies both across plant species and geographical locations. Phyllosphere bacteria can have important effects on plant health. The sweet chestnut (Castanea sativa Mill.) is an economically important tree species affected worldwide by the fungal pathogens Cryphonectria parasitica and Phytophthora cinnamomi. We examined the culturable phyllosphere bacterial community of the sweet chestnut at two nearby locations in Central Spain in order to know its geographical variability and to explore its potential as source of biological control agents against these two pathogenic fungi. The bacterial diversity at strain level was high but it varied significantly between locations; however, phylotype richness and diversity were more comparable. The isolates were affiliated with the phyla Actinobacteria, Firmicutes and Proteobacteria. Most of them were members of recognized bacterial species, with a notable proportion of representative of the genera Dietzia and Lonsdalea, but a small fraction of the strains revealed the existence of several potential novel species or even genera. Antagonism tests showed the occurrence in the chestnut phyllosphere of bacterial strains potentially useful as biological control agents against the two pathogenic fungi, some of which belong to species never before described as fungal antagonists. Chestnut phyllosphere, therefore, contains a great diversity of culturable bacteria and may represent an untapped source of potential biocontrol agents against the fungi causing blight and ink diseases of this tree species.
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Affiliation(s)
- Angel Valverde
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA), Consejo Superior de Investigaciones Científicas (CSIC), 37008 Salamanca, Spain.,Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria 0028, South Africa
| | - María González-Tirante
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA), Consejo Superior de Investigaciones Científicas (CSIC), 37008 Salamanca, Spain.,Estación Biológica de Doñana, 41001 Sevilla, Spain
| | - Marisol Medina-Sierra
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA), Consejo Superior de Investigaciones Científicas (CSIC), 37008 Salamanca, Spain.,Escuela de Producción Agropecuaria, Group GRICA (Grupo de Investigación en Ciencias Agrarias), Facultad de Ciencias Agrarias, Universidad de Antioquia, Medellín, Colombia
| | - Raúl Rivas
- Departamento de Microbiología y Genética, Universidad de Salamanca, 37007 Salamanca, Spain.,Unidad Asociada Universidad de Salamanca-CSIC (IRNASA), Salamanca, Spain
| | - Ignacio Santa-Regina
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA), Consejo Superior de Investigaciones Científicas (CSIC), 37008 Salamanca, Spain.,Unidad Asociada Universidad de Salamanca-CSIC (IRNASA), Salamanca, Spain
| | - José M Igual
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA), Consejo Superior de Investigaciones Científicas (CSIC), 37008 Salamanca, Spain.,Unidad Asociada Universidad de Salamanca-CSIC (IRNASA), Salamanca, Spain
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