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van den Berg N, Swart V, Backer R, Fick A, Wienk R, Engelbrecht J, Prabhu SA. Advances in Understanding Defense Mechanisms in Persea americana Against Phytophthora cinnamomi. FRONTIERS IN PLANT SCIENCE 2021; 12:636339. [PMID: 33747014 PMCID: PMC7971113 DOI: 10.3389/fpls.2021.636339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/18/2021] [Indexed: 06/03/2023]
Abstract
Avocado (Persea americana) is an economically important fruit crop world-wide, the production of which is challenged by notable root pathogens such as Phytophthora cinnamomi and Rosellinia necatrix. Arguably the most prevalent, P. cinnamomi, is a hemibiotrophic oomycete which causes Phytophthora root rot, leading to reduced yields and eventual tree death. Despite its' importance, the development of molecular tools and resources have been historically limited, prohibiting significant progress toward understanding this important host-pathogen interaction. The development of a nested qPCR assay capable of quantifying P. cinnamomi during avocado infection has enabled us to distinguish avocado rootstocks as either resistant or tolerant - an important distinction when unraveling the defense response. This review will provide an overview of our current knowledge on the molecular defense pathways utilized in resistant avocado rootstock against P. cinnamomi. Notably, avocado demonstrates a biphasic phytohormone profile in response to P. cinnamomi infection which allows for the timely expression of pathogenesis-related genes via the NPR1 defense response pathway. Cell wall modification via callose deposition and lignification have also been implicated in the resistant response. Recent advances such as composite plant transformation, single nucleotide polymorphism (SNP) analyses as well as genomics and transcriptomics will complement existing molecular, histological, and biochemical assay studies and further elucidate avocado defense mechanisms.
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Affiliation(s)
- Noëlani van den Berg
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Velushka Swart
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Robert Backer
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Alicia Fick
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Raven Wienk
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Juanita Engelbrecht
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - S. Ashok Prabhu
- Hans Merensky Chair in Avocado Research, University of Pretoria, Pretoria, South Africa
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
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Sayari M, van der Nest MA, Steenkamp ET, Adegeye OO, Marincowitz S, Wingfield BD. Agrobacterium-mediated transformation of Ceratocystis albifundus. Microbiol Res 2019; 226:55-64. [PMID: 31284945 DOI: 10.1016/j.micres.2019.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/01/2019] [Accepted: 05/23/2019] [Indexed: 11/17/2022]
Abstract
Functional association between genomic loci and specific biological traits remains lacking in many fungi, including the African tree pathogen Ceratocystis albifundus. This is mainly because of the absence of suitable transformation systems for allowing genetic manipulation of this and other fungi. Here, we present an optimized protocol for Agrobacterium tumefaciens-mediated transformation of C. albifundus. Strain AGL-1 of A. tumefaciens and four binary T-DNA vectors (conferring hygromycin B or geneticin resistance and/or expressing the green fluorescent protein [GFP]) were used for transforming germinated conidia of three isolates of C. albifundus. Stable expression of these T-DNA-encoded traits was confirmed through sequential sub-culturing of fungal transformants on selective and non-selective media and by using PCR and sequence analysis. Single-copy integration of the respective T-DNAs into the genomes of these fungi was confirmed using Southern hybridization analysis. The range of experimental parameters determined and optimised included: (i) concentrations of hygromycin B and geneticin required for inhibiting growth of the wild type fungus and (ii) the dependence of transformation on acetosyringone for inducing the bacterium's virulence genes, as well as (iii) the duration of fungus-bacterium co-cultivation periods and (iv) the concentrations of fungal conidia and bacterial cells used for the latter. The system developed in this study is stable with a high-efficiency, yielding up to 400 transformants per 106 conidia. This is the first report of a transformation protocol for C. albifundus and its availability will be invaluable for functional studies in this important fungus.
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Affiliation(s)
- M Sayari
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
| | - M A van der Nest
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa; Biotechnology Platform, Agricultural Research Council, Onderstepoort Campus, Pretoria, South Africa
| | - E T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
| | - O O Adegeye
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
| | - S Marincowitz
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
| | - B D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa.
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Attri C, Kulshrestha S. Restriction enzyme-mediated insertional mutagenesis: an efficient method of Rosellinia necatrix transformation. Arch Microbiol 2017; 200:189-194. [PMID: 29196779 DOI: 10.1007/s00203-017-1466-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 11/17/2017] [Accepted: 11/29/2017] [Indexed: 11/25/2022]
Abstract
Rosellinia necatrix: causing root rot disease is a very destructive pathogen of woody plants and is responsible for yield losses to a large number of fruit trees. The genetic analysis of this pathogen has not been picked up because of difficulty in generating mutations in Rosellinia necatrix for many reasons. A number of methods have been proposed for inducing mutations in Rosellinia necatrix but none of them proved worth because of very low transformation efficiencies. Here, we propose an efficient method for Rosellinia necatrix protoplast production, where protoplasts in the tune of 107 per ml can be easily generated. We also propose a restriction enzyme-mediated integration (REMI)-based methods for efficient transformation of Rosellinia necatrix. In the present study, an approximate of 800 transformants was obtained from 5 μg of linearized plasmid. Out of 47 single spored transformants analyzed, only 33 showed hygromycin gene amplification using PCR and only 19 transformants showed single gene integration in southern hybridization, which accounted for single gene integration percentage of 42%, highest amongst all the previous reports on Rosellinia necatrix transformations. Some of the transformants studied for pathogenicity phenotype also showed a marked reduction in pathogenicity. Thus, in the present investigation, 42% single gene integrations among the transformed colonies can be considered as excellent transformation efficiency.
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Affiliation(s)
- Chandrika Attri
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh, 173229, India
| | - Saurabh Kulshrestha
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh, 173229, India.
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Zhang M, Pereira e Silva MDC, Chaib De Mares M, van Elsas JD. The mycosphere constitutes an arena for horizontal gene transfer with strong evolutionary implications for bacterial-fungal interactions. FEMS Microbiol Ecol 2014; 89:516-26. [DOI: 10.1111/1574-6941.12350] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- MiaoZhi Zhang
- Department of Microbial Ecology; Centre for Life Sciences; University of Groningen; Groningen The Netherlands
| | | | - Maryam Chaib De Mares
- Department of Microbial Ecology; Centre for Life Sciences; University of Groningen; Groningen The Netherlands
| | - Jan Dirk van Elsas
- Department of Microbial Ecology; Centre for Life Sciences; University of Groningen; Groningen The Netherlands
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