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Wang K, Xu C, Li D, Gu Z. Physiological and Biochemical Responses of Sagittaria trifolia L. to Phytotoxic Ethyl Acetate Fungal Extract from Curvularia lunata Strain CLST-01. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12091758. [PMID: 37176815 PMCID: PMC10180700 DOI: 10.3390/plants12091758] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/23/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Curvularia lunata (No. CLST-01), a fungal pathogen isolated from the threeleaf arrowhead (Sagittaria trifolia L.), has been proposed as a potential mycoherbicide for grass weeds. This paper investigated the physiological and biochemical effects of CLST-01 phytotoxic ethyl acetate fungi extract on the leaves of the threeleaf arrowhead. The results showed that the ethyl acetate fungi extract from CLST-01 can accelerate damage to the cell membrane, increase the production of malondialdehyde, and damage the cellular structure, which could decrease the number of chloroplasts after 96 h treatments. In addition, the content of chlorophyll was reduced by 49.5%, and the net photosynthetic rate, stomatal conductance, and transpiration rate were inhibited. The rates of inhibition were 90.13%, 83.74%, and 79.31%, respectively, and the intercellular CO2 concentration increased by 51.87% on Day 9 after treatment with a concentration of 200 μg/mL. In summary, the phytotoxic ethyl acetate fungal extract from C. lunata CLST-01 can inhibit the photosynthesis of the threeleaf arrowhead leaves, destroy the ultrastructure of leaves, and affect the growth of this invasive weed. Therefore, it has the potential to be developed into a mycoherbicide for weed control in crops as a natural photosynthetic inhibitor.
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Affiliation(s)
- Kai Wang
- Department of Pesticide Science, Plant Protection College, Shenyang Agricultural University, Shenyang 110866, China
| | - Chang Xu
- Department of Pesticide Science, Plant Protection College, Shenyang Agricultural University, Shenyang 110866, China
| | - Dongyang Li
- Department of Pesticide Science, Plant Protection College, Shenyang Agricultural University, Shenyang 110866, China
| | - Zumin Gu
- Department of Pesticide Science, Plant Protection College, Shenyang Agricultural University, Shenyang 110866, China
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Silva FMDO, Bulgarelli RG, Mubeen U, Caldana C, Andrade SAL, Mazzafera P. Low phosphorus induces differential metabolic responses in eucalyptus species improving nutrient use efficiency. FRONTIERS IN PLANT SCIENCE 2022; 13:989827. [PMID: 36186027 PMCID: PMC9520260 DOI: 10.3389/fpls.2022.989827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/11/2022] [Indexed: 06/16/2023]
Abstract
Phosphorus (P) is a vital nutrient for plant growth. P availability is generally low in soils, and plant responses to low P availability need to be better understood. In a previous study, we studied the growth and physiological responses of 24 species to low P availability in the soil and verified of eucalypts, five (Eucalyptus acmenoides, E. grandis, E. globulus, E. tereticornis, and Corymbia maculata) contrasted regarding their efficiency and responsiveness to soil P availability. Here, we obtained the metabolomic and lipidomic profile of leaves, stems, and roots from these species growing under low (4.5 mg dm-3) and sufficient (10.8 mg dm-3) P in the soil. Disregarding the level of P in the soils, P allocation was always higher in the stems. However, when grown in the P-sufficient soil, the stems steadily were the largest compartment of the total plant P. Under low P, the relative contents of primary metabolites, such as amino acids, TCA cycle intermediates, organic acids and carbohydrates, changed differently depending on the species. Additionally, phosphorylated metabolites showed enhanced turnover or reductions. While photosynthetic efficiencies were not related to higher biomass production, A/Ci curves showed that reduced P availability increased the eucalypt species' Vcmax, Jmax and photosynthetic P-use efficiency. Plants of E. acmenoides increased galactolipids and sulfolipids in leaves more than other eucalypt species, suggesting that lipid remodelling can be a strategy to cope with the P shortage in this species. Our findings offer insights to understand genotypic efficiency among eucalypt species to accommodate primary metabolism under low soil P availability and eventually be used as biochemical markers for breeding programs.
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Affiliation(s)
| | | | - Umarah Mubeen
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Camila Caldana
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Sara Adrian L. Andrade
- Department of Plant Biology, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Paulo Mazzafera
- Department of Plant Biology, Institute of Biology, State University of Campinas, Campinas, Brazil
- Department of Crop Production, Luiz de Queiroz College of Agriculture, University of São Paulo, São Paulo, Brazil
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Maiden NA, Syd Ali N, Ahmad K, Atan S, Wong MY. Growth and physiological responses of Hevea brasiliensis to Rigidoporus microporus infection. J RUBBER RES 2022. [DOI: 10.1007/s42464-022-00156-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Gomez‐Gallego M, Galiano L, Martínez‐Vilalta J, Stenlid J, Capador‐Barreto HD, Elfstrand M, Camarero JJ, Oliva J. Interaction of drought- and pathogen-induced mortality in Norway spruce and Scots pine. PLANT, CELL & ENVIRONMENT 2022; 45:2292-2305. [PMID: 35598958 PMCID: PMC9546048 DOI: 10.1111/pce.14360] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Pathogenic diseases frequently occur in drought-stressed trees. However, their contribution to the process of drought-induced mortality is poorly understood. We combined drought and stem inoculation treatments to study the physiological processes leading to drought-induced mortality in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) saplings infected with Heterobasidion annosum s.s. We analysed the saplings' water status, gas exchange, nonstructural carbohydrates (NSCs) and defence responses, and how they related to mortality. Saplings were followed for two growing seasons, including an artificially induced 3-month dormancy period. The combined drought and pathogen treatment significantly increased spruce mortality; however, no interaction between these stressors was observed in pine, although individually each stressor caused mortality. Our results suggest that pathogen infection decreased carbon reserves in spruce, reducing the capacity of saplings to cope with drought, resulting in increased mortality rates. Defoliation, relative water content and the starch concentration of needles were predictors of mortality in both species under drought and pathogen infection. Infection and drought stress create conflicting needs for carbon to compartmentalize the pathogen and to avoid turgor loss, respectively. Heterobasidion annosum reduces the functional sapwood area and shifts NSC allocation patterns, reducing the capacity of trees to cope with drought.
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Affiliation(s)
- Mireia Gomez‐Gallego
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
- Université de Lorraine, INRAE, IAMNancyFrance
| | - Lucia Galiano
- CREAF, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
| | - Jordi Martínez‐Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
| | - Jan Stenlid
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Hernán D. Capador‐Barreto
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Malin Elfstrand
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | | | - Jonàs Oliva
- Department of Crop and Forest SciencesUniversity of LleidaLleidaSpain
- Joint Research Unit CTFC‐AGROTECNIOLleidaSpain
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Sun H, Zhang H, Xu Z, Wang Y, Liu X, Li Y, Tian B, Sun G, Zhang H. TMT-based quantitative proteomic analysis of the effects of Pseudomonas syringae pv. tabaci (Pst) infection on photosynthetic function and the response of the MAPK signaling pathway in tobacco leaves. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 166:657-667. [PMID: 34214776 DOI: 10.1016/j.plaphy.2021.06.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
To reveal the mechanism of photosynthesis inhibition by infection and the response of the MAPK signaling pathway to pathogen infection, tobacco leaves were inoculated with Pseudomonas syringae pv. tabaci (Pst), and the effects of Pst infection on photosynthesis of tobacco leaves were studied by physiological and proteomic techniques, with a focus on MAPK signaling pathway related proteins. Pst infection was observed to lead to the degradation of chlorophyll (especially Chl b) in tobacco leaves and the down-regulation of light harvesting antenna proteins expression, thus limiting the light harvesting ability. The photosystem II and I (PSII and PSI) activities were also decreased, and Pst infection inhibited the utilization of light and CO2. Proteomic analyses showed that the number of differentially expressed proteins (DEPs) under Pst infection at 3 d were significantly higher than at 1 d, especially the number of down-regulated proteins. The KEGG enrichment of DEPs was mainly enriched in the energy metabolism processes such as photosynthesis antenna proteins and photosynthesis. The down-regulation of chlorophyll a-b binding protein, photosynthetic electron transport related proteins (e.g., PSII and PSI core proteins, the Cytb6/f complex, PC, Fd, FNR), ATP synthase subunits, and key enzymes in the Calvin cycle were the key changes associated with Pst infection that may inhibit tobacco photosynthesis. The effect of Pst infection on the PSII electron acceptor side was significantly greater than that on the PSII donor side. The main factor that decreased the photosynthetic ability of tobacco leaves with Pst infection at 1 d may be the inhibition of photochemical reactions leading to an insufficient supply of ATP, rather than decreased expression of enzymes involved in the Calvin cycle. At 1 d into Pst infection, the PSII regulated energy dissipation yield Y(NPQ) may play a role in preventing photosynthetic inhibition in tobacco leaves, but the long-term Pst infection significantly inhibited Y(NPQ) and the expression of PsbS proteins. Proteins involved in the MAPK signaling pathway were up-regulated, suggesting the MAPK signaling pathway was activated to respond to Pst infection. However, at the late stage of Pst infection (at 3 d), MAPK signaling pathway proteins were degraded, and the defense function of the MAPK signaling pathway in tobacco leaves was damaged.
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Affiliation(s)
- Hongwei Sun
- Mudanjiang Tobacco Science Research Institute, Mudanjiang, Heilongjiang, China
| | - Hongbo Zhang
- College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Zisong Xu
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Yue Wang
- College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Xiaoqian Liu
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Yuanyuan Li
- College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Bei Tian
- College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Guangyu Sun
- College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Huihui Zhang
- College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China.
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Fourie A, de Jonge R, van der Nest MA, Duong TA, Wingfield MJ, Wingfield BD, Barnes I. Genome comparisons suggest an association between Ceratocystis host adaptations and effector clusters in unique transposable element families. Fungal Genet Biol 2020; 143:103433. [PMID: 32652232 DOI: 10.1016/j.fgb.2020.103433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 06/18/2020] [Accepted: 06/30/2020] [Indexed: 01/04/2023]
Abstract
Ceratocystis fimbriata is a host specific fungal pathogen of sweet potato (Ipomoea batatas). The closely related species, C. manginecans, is an important pathogen of trees (e.g. Acacia mangium and Mangifera indica) but has never been isolated from tuber crops. The genetic factors that determine the host range and host specificity of these species have not been determined. The aim of this study was to compare the genomes of C. fimbriata and C. manginecans in order to identify species-specific genetic differences that could be associated with host specificity. This included whole-genome alignments as well as comparisons of gene content and transposable elements (TEs). The genomes of the two species were found to be very similar, sharing similar catalogues of CAZymes, peptidases and lipases. However, the genomes of the two species also varied, harbouring species-specific genes (e.g. small secreted effectors, nutrient processing proteins and stress response proteins). A portion of the TEs identified (17%) had a unique distribution in each species. Transposable elements appeared to have played a prominent role in the divergence of the two species because they were strongly associated with chromosomal translocations and inversions as well as with unique genomic regions containing species-specific genes. Two large effector clusters, with unique TEs in each species, were identified. These effectors displayed non-synonymous mutations and deletions, conserved within a species, and could serve as mutational hot-spots for the development of host specificity in the two species.
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Affiliation(s)
- Arista Fourie
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Ronnie de Jonge
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht 3584 CH, the Netherlands
| | - Magriet 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, Private Bag X05, Onderstepoort 0110, 0002, South Africa
| | - Tuan A Duong
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Michael J Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Irene Barnes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa.
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Teshome DT, Zharare GE, Naidoo S. The Threat of the Combined Effect of Biotic and Abiotic Stress Factors in Forestry Under a Changing Climate. FRONTIERS IN PLANT SCIENCE 2020; 11:601009. [PMID: 33329666 PMCID: PMC7733969 DOI: 10.3389/fpls.2020.601009] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/05/2020] [Indexed: 05/11/2023]
Abstract
Plants encounter several biotic and abiotic stresses, usually in combination. This results in major economic losses in agriculture and forestry every year. Climate change aggravates the adverse effects of combined stresses and increases such losses. Trees suffer even more from the recurrence of biotic and abiotic stress combinations owing to their long lifecycle. Despite the effort to study the damage from individual stress factors, less attention has been given to the effect of the complex interactions between multiple biotic and abiotic stresses. In this review, we assess the importance, impact, and mitigation strategies of climate change driven interactions between biotic and abiotic stresses in forestry. The ecological and economic importance of biotic and abiotic stresses under different combinations is highlighted by their contribution to the decline of the global forest area through their direct and indirect roles in forest loss and to the decline of biodiversity resulting from local extinction of endangered species of trees, emission of biogenic volatile organic compounds, and reduction in the productivity and quality of forest products and services. The abiotic stress factors such as high temperature and drought increase forest disease and insect pest outbreaks, decrease the growth of trees, and cause tree mortality. Reports of massive tree mortality events caused by "hotter droughts" are increasing all over the world, affecting several genera of trees including some of the most important genera in plantation forests, such as Pine, Poplar, and Eucalyptus. While the biotic stress factors such as insect pests, pathogens, and parasitic plants have been reported to be associated with many of these mortality events, a considerable number of the reports have not taken into account the contribution of such biotic factors. The available mitigation strategies also tend to undermine the interactive effect under combined stresses. Thus, this discussion centers on mitigation strategies based on research and innovation, which build on models previously used to curb individual stresses.
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Affiliation(s)
- Demissew Tesfaye Teshome
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | | | - Sanushka Naidoo
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
- *Correspondence: Sanushka Naidoo,
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Fungal canker pathogens trigger carbon starvation by inhibiting carbon metabolism in poplar stems. Sci Rep 2019; 9:10111. [PMID: 31300723 PMCID: PMC6626041 DOI: 10.1038/s41598-019-46635-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 07/01/2019] [Indexed: 12/12/2022] Open
Abstract
Carbon starvation is the current leading hypothesis of plant mortality mechanisms under drought stress; recently, it is also used to explain tree die-off in plant diseases. However, the molecular biology of the carbon starvation pathway is unclear. Here, using a punch inoculation system, we conducted transcriptome and physiological assays to investigate pathogen response in poplar stems at the early stages of Botryosphaeria and Valsa canker diseases. Transcriptome assays showed that the majority of differentially expressed genes (DEGs) in stem phloem and xylem, such as genes involved in carbon metabolism and transportation, aquaporin genes (in xylem) and genes related to the biosynthesis of secondary metabolites and the phenylpropanoid pathway (related to lignin synthesis), were downregulated at 7 days after inoculation (DAI). Results also showed that the expression of the majority of disease-resistance genes upregulated in poplar stems, which may be connected with the downregulation expression of the majority of WRKY family genes. Physiological assays showed that transpiration rate decreased but WUE (water use efficiency) increased the 3 and 7 DAI, while the net photosynthetic rate decreased at 11 DAI in Botryosphaeria infected poplars (ANOVA, P < 0.05). The NSC (non-structural carbohydrates) content assays showed that the soluble sugar content of stem phloem samples increased at 3, 7, and 11 DAI that might due to the impede of pathogen infection. However, soluble sugar content of stem xylem and root samples decreased at 11 DAI; in contrast, the starch content unchanged. Therefore, results revealed a chronological order of carbon related molecular and physiological performance: declination of genes involved in carbon and starch metabolism first (at least at 7 DAI), declination of assimilation and carbon reserve (at 11 DAI) second. Results implied a potential mechanism that affects the host carbon reserve, by directly inhibiting the expression of genes involved in carbon metabolism and transport.
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Fourie A, van der Nest MA, de Vos L, Wingfield MJ, Wingfield BD, Barnes I. QTL mapping of mycelial growth and aggressiveness to distinct hosts in Ceratocystis pathogens. Fungal Genet Biol 2019; 131:103242. [PMID: 31212023 DOI: 10.1016/j.fgb.2019.103242] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 10/26/2022]
Abstract
Some species of Ceratocystis display strong host specificity, such as C. fimbriata sensu stricto that is restricted to sweet potato (Ipomoea batatas) as host. In contrast, the closely related C. manginecans, infects Acacia mangium and Mangifera indica but is not pathogenic to I. batatas. Despite the economic importance of these fungi, knowledge regarding the genetic factors that influence their pathogenicity and host specificity is limited. A recent inheritance study, based on an interspecific cross between C. fimbriata and C. manginecans and the resultant 70 F1 progeny, confirmed that traits such as mycelial growth rate, spore production and aggressiveness on A. mangium and I. batatas are regulated by multiple genes. In the present study, a quantitative trait locus (QTL) analysis was performed to determine the genomic loci associated with these traits. All 70 progeny isolates were genotyped with SNP markers and a linkage map was constructed. The map contained 467 SNPs, distributed across nine linkage groups, with a total length of 1203 cm. Using the progeny genotypes and phenotypes, one QTL was identified on the linkage map for mycelial growth rate, one for aggressiveness to A. mangium and two for aggressiveness to I. batatas (P < 0.05). Two candidate genes, likely associated with mycelial growth rate, were identified in the QTL region. The three QTLs associated with aggressiveness to different hosts contained candidate genes involved in protein processing, detoxification and regions with effector genes and high transposable element density. The results provide a foundation for studies considering the function of genes regulating various quantitative traits in Ceratocystis.
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Affiliation(s)
- Arista Fourie
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Magriet 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, Private Bag X05, Onderstepoort 0110 0002, South Africa
| | - Lieschen de Vos
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Michael J Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Irene Barnes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa.
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Hossain M, Veneklaas EJ, Hardy GESJ, Poot P. Tree host-pathogen interactions as influenced by drought timing: linking physiological performance, biochemical defence and disease severity. TREE PHYSIOLOGY 2019; 39:6-18. [PMID: 30299517 DOI: 10.1093/treephys/tpy113] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/13/2018] [Indexed: 05/20/2023]
Abstract
There is increasing concern about tree mortality around the world due to climatic extremes and associated shifts in pest and pathogen dynamics. Yet, empirical studies addressing the interactive effect of biotic and abiotic stress on plants are very rare. Therefore, in this study, we examined the interaction between drought stress and a canker pathogen, Quambalaria coyrecup, on the eucalypt - Corymbia calophylla (marri), which is experiencing increasing drought stress. We hypothesized that drought stress would increase marri's susceptibility to canker disease, and cankers would have the largest negative effect on plants that are already drought stressed before pathogen inoculation. To test the hypotheses, in a glasshouse, marri saplings were exposed to drought either before or after pathogen inoculation, or were well-watered or droughted throughout the experiment either with or without inoculation. Canker development was greater in well-watered saplings than in droughted saplings, with the fastest development occurring in well-watered saplings that had experienced drought stress before inoculation. Irrespective of water treatments, marri saplings employed phenol-based localized biochemical defence against the pathogen. Drought reduced photosynthesis and growth, however, a negative effect of canker disease on saplings' physiological performance was only observed in well-watered saplings. In well-watered saplings, canker-induced loss of sapwood function contributed to reduced whole-plant hydraulic conductance, photosynthesis and growth. The results provide evidence that timing of drought stress influences host physiology, and host condition influences canker disease susceptibility through differences in induced biochemical defence mechanisms. The observations highlight the importance of explicitly incorporating abiotic and biotic stress, as well as their interactions, in future studies of tree mortality in drought-prone regions worldwide.
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Affiliation(s)
- Mohitul Hossain
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, Australia
| | - Erik J Veneklaas
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, Australia
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, Australia
| | - Giles E St J Hardy
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Pieter Poot
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, Australia
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