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Khan AR, Wicaksono WA, Ott NJ, Poret-Peterson AT, Browne GT. Random forest analysis reveals taxa predictive of Prunus replant disease in peach root microbiomes. PLoS One 2022; 17:e0275587. [PMID: 36227955 PMCID: PMC9560047 DOI: 10.1371/journal.pone.0275587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 09/20/2022] [Indexed: 11/06/2022] Open
Abstract
Successive plantings of Prunus species produce suboptimal growth and yield in many California soils due to a poorly understood soilborne disease complex, Prunus replant disease (PRD). We explored the hypothesis that PRD is mediated by microbial taxa in roots of Nemaguard peach, a rootstock for almond and other stone fruits. In a greenhouse bioassay, portions of 10 replant soils were treated with fumigation or pasteurization or left untreated as a control before being planted with peach seedlings. Ten weeks after planting, seedlings were considered PRD-affected if their top fresh weights in the control were significantly reduced, compared to the weights in pasteurization and fumigation treatments; plants with equivalent top weights in all treatments were considered to be non-affected. The roots were washed from the soil, frozen, extracted for total DNA, and used for metabarcoding of rRNA gene amplicons from bacteria, fungi, and oomycetes. High-throughput amplicon sequencing revealed that root microbial community shifts resulted from preplant treatments, and specific taxa were associated with PRD induction among controls. Random forest (RF) analysis discriminated effectively between PRD-affected and non-affected root communities. Among the 30 RF top-ranked amplicon sequence variant (ASV) predictors, 26 were bacteria, two were oomycetes, and two were fungi. Among them, only Streptomyces scabiei, Steroidobacter denitrificans, Streptomyces bobili, and Pythium mamillatum had root abundances ≥5% that were either associated positively (former two ASVs) or negatively (latter two) with PRD. Thus, our findings were consistent with microbial mediation of PRD in roots and suggested taxa that may be involved in the mediation.
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Affiliation(s)
- Abdur R. Khan
- Department of Plant Pathology, University of California, Davis, California, United States of America
| | - Wisnu A. Wicaksono
- Department of Plant Pathology, University of California, Davis, California, United States of America
| | - Natalia J. Ott
- USDA-ARS Crops Pathology and Genetics Research Unit, Davis, California, United States of America
| | - Amisha T. Poret-Peterson
- USDA-ARS Crops Pathology and Genetics Research Unit, Davis, California, United States of America
| | - Greg T. Browne
- USDA-ARS Crops Pathology and Genetics Research Unit, Davis, California, United States of America
- * E-mail:
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Hu X, Gu H, Wang Y, Liu J, Yu Z, Li Y, Jin J, Liu X, Dai Q, Wang G. Succession of soil bacterial communities and network patterns in response to conventional and biodegradable microplastics: A microcosmic study in Mollisol. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129218. [PMID: 35739740 DOI: 10.1016/j.jhazmat.2022.129218] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/12/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Significant soil contamination of microplastics (MPs) by the application of agricultural mulching films has aroused global concern, however, the effects of conventional and biodegradable MPs on the dynamics of soil microbial communities and network patterns have not been sufficiently reported. In this study, we conducted a soil microcosmic experiment by adding low-density polyethylene and biodegradable MPs (PE and BD) into a black soil at the dosages of 0 % (CK), 0.1 % (low-dose, w/w), 1 % (medium-dose, w/w) and 5 % (high-dose, w/w), and soils were sampled on the 15th, 30th, 60th and 90th day of soil incubation for high-throughput sequencing. The results showed that the incubation time was the most influential factor driving the variations in bacterial community structures, and significant effects of MP dosages and types were also detected. With the increase in MP dosage, bacterial diversity markedly increased and decreased at the beginning (D15) and end of sampling day (D90), respectively. Compared to CK, BD induced a larger community dissimilarity than PE and tended to enrich environmentally friendly taxa, while PE likely promoted the growth of hazardous taxa. Moreover, BD simplified interspecies interactions compared to the networks of PE and CK, and Nitrospira was identified as a keystone species in both PE and BD networks. These findings provide new insights into the influences of conventional and biodegradable MPs on the succession patterns of soil bacterial communities, and further studies are needed to explore the soil metabolic potentials affected by the presence of MPs.
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Affiliation(s)
- Xiaojing Hu
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Haidong Gu
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Yongbin Wang
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Junjie Liu
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Zhenhua Yu
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Yansheng Li
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Jian Jin
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Xiaobing Liu
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Qingwen Dai
- Hangzhou Sci-Doer Technology Co., Ltd, Hangzhou 311100, China
| | - Guanghua Wang
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China.
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Anguita-Maeso M, Ares-Yebra A, Haro C, Román-Écija M, Olivares-García C, Costa J, Marco-Noales E, Ferrer A, Navas-Cortés JA, Landa BB. Xylella fastidiosa Infection Reshapes Microbial Composition and Network Associations in the Xylem of Almond Trees. Front Microbiol 2022; 13:866085. [PMID: 35910659 PMCID: PMC9330911 DOI: 10.3389/fmicb.2022.866085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 05/26/2022] [Indexed: 11/28/2022] Open
Abstract
Xylella fastidiosa represents a major threat to important crops worldwide including almond, citrus, grapevine, and olives. Nowadays, there are no efficient control measures for X. fastidiosa, and the use of preventive measures and host resistance represent the most practical disease management strategies. Research on vessel-associated microorganisms is gaining special interest as an innate natural defense of plants to cope against infection by xylem-inhabiting pathogens. The objective of this research has been to characterize, by next-generation sequencing (NGS) analysis, the microbial communities residing in the xylem sap of almond trees affected by almond leaf scorch disease (ALSD) in a recent X. fastidiosa outbreak occurring in Alicante province, Spain. We also determined community composition changes and network associations occurring between xylem-inhabiting microbial communities and X. fastidiosa. For that, a total of 91 trees with or without ALSD symptoms were selected from a total of eight representative orchards located in five municipalities within the X. fastidiosa-demarcated area. X. fastidiosa infection in each tree was verified by quantitative polymerase chain reaction (qPCR) analysis, with 54% of the trees being tested X. fastidiosa-positive. Globally, Xylella (27.4%), Sphingomonas (13.9%), and Hymenobacter (12.7%) were the most abundant bacterial genera, whereas Diplodia (30.18%), a member of the family Didymellaceae (10.7%), and Aureobasidium (9.9%) were the most predominant fungal taxa. Furthermore, principal coordinate analysis (PCoA) of Bray–Curtis and weighted UniFrac distances differentiated almond xylem bacterial communities mainly according to X. fastidiosa infection, in contrast to fungal community structure that was not closely related to the presence of the pathogen. Similar results were obtained when X. fastidiosa reads were removed from the bacterial data set although the effect was less pronounced. Co-occurrence network analysis revealed negative associations among four amplicon sequence variants (ASVs) assigned to X. fastidiosa with different bacterial ASVs belonging to 1174-901-12, Abditibacterium, Sphingomonas, Methylobacterium–Methylorubrum, Modestobacter, Xylophilus, and a non-identified member of the family Solirubrobacteraceae. Determination of the close-fitting associations between xylem-inhabiting microorganisms and X. fastidiosa may help to reveal specific microbial players associated with the suppression of ALSD under high X. fastidiosa inoculum pressure. These identified microorganisms would be good candidates to be tested in planta, to produce almond plants more resilient to X. fastidiosa infection when inoculated by endotherapy, contributing to suppress ALSD.
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Affiliation(s)
- Manuel Anguita-Maeso
- Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain
- *Correspondence: Manuel Anguita-Maeso,
| | - Aitana Ares-Yebra
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
- Laboratory for Phytopathology, Instituto Pedro Nunes, Coimbra, Portugal
| | - Carmen Haro
- Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain
| | - Miguel Román-Écija
- Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain
| | - Concepción Olivares-García
- Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain
| | - Joana Costa
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
- Laboratory for Phytopathology, Instituto Pedro Nunes, Coimbra, Portugal
| | - Ester Marco-Noales
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| | - Amparo Ferrer
- Servicio de Sanidad Vegetal, Generalitat Valenciana, Valencia, Spain
| | - Juan A. Navas-Cortés
- Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain
| | - Blanca B. Landa
- Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain
- Blanca B. Landa,
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