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Yu H, Su L, Jia W, Jia M, Pan H, Zhang X. Molecular Mechanism Underlying Pathogenicity Inhibition by Chitosan in Cochliobolus heterostrophus. J Agric Food Chem 2024; 72:3926-3936. [PMID: 38365616 DOI: 10.1021/acs.jafc.3c07968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
Chitosan, as a natural nontoxic biomaterial, has been demonstrated to inhibit fungal growth and enhance plant defense against pathogen infection. However, the antifungal pattern and mechanism of how chitosan application evokes plant defense are poorly elucidated. Herein, we provide evidence that chitosan exposure is fungicidal to C. heterostrophus. Chitosan application impairs conidia germination and appressorium formation of C. heterostrophus and has a pronounced effect on reactive oxygen species production, thereby preventing infection in maize. In addition, the toxicity of chitosan to C. heterostrophus requires Mkk1 and Mps1, two key components in the cell wall integrity pathway. The Δmkk1 and Δmps1 mutants were more tolerant to chitosan than the wild-type. To dissect chitosan-mediated plant defense response to C. heterostrophus, we conducted a metabolomic analysis, and several antifungal compounds were upregulated in maize upon chitosan treatment. Taken together, our findings provide a comprehensive understanding of the mechanism of chitosan-alleviated infection of C. heterostrophus, which would promote the application of chitosan in plant protection in agriculture.
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Affiliation(s)
- Huilin Yu
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Longhao Su
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Wantong Jia
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Mengjiao Jia
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Hongyu Pan
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Xianghui Zhang
- College of Plant Science, Jilin University, Changchun 130062, China
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Jia W, Yu H, Fan J, Zhang J, Pan H, Zhang X. The histidine kinases regulate allyl-isothiocyanate sensitivity in Cochliobolus heterostrophus. Pest Manag Sci 2024; 80:463-472. [PMID: 37743431 DOI: 10.1002/ps.7777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 08/23/2023] [Accepted: 09/25/2023] [Indexed: 09/26/2023]
Abstract
BACKGROUD Two-component histidine kinase (HK) phosphorelay signaling systems play important roles in differentiation, virulence, secondary metabolite production and response to environmental signals. Allyl isothiocyanate (A-ITC) is a hydrolysis product of glucosinolates with excellent antifungal activity. Our previous study indicated that the mycelial growth of Cochliobolus heterostrophus was significantly hindered by A-ITC. However, the function of HK in regulating A-ITC sensitivity was not clear in C. heterostrophus, the causal agent of Southern corn leaf blight. RESULTS In this study, the role of HKs was investigated in C. heterostrophus. Deletion of the HK coding gene ChNIK1 resulted in dramatically increased sensitivity of C. heterostrophus to A-ITC. In addition, ΔChnik1 mutant exhibited significantly decreased conidiation and increased sensitivity to NaCl, KCl, tebuconazole and azoxystrobin, but deletion of the other five HK genes did not affect the A-ITC sensitivity of C. heterostrophus. ChSLN1, ChNIK4, ChNIK8 and ChMAK2 are essential for conidiation and response to H2 O2 and sodium dodecyl sulfate. However, deletion of NIKs had on effect on significant virulence. CONCLUSION Our findings demonstrate that the HKs play different roles in A-ITC sensitivity in C. heterostrophus. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Wantong Jia
- College of Plant Science, Jilin University, Changchun, China
| | - Huilin Yu
- College of Plant Science, Jilin University, Changchun, China
| | - Jinyu Fan
- College of Plant Science, Jilin University, Changchun, China
| | - Jiyue Zhang
- College of Plant Science, Jilin University, Changchun, China
| | - Hongyu Pan
- College of Plant Science, Jilin University, Changchun, China
| | - Xianghui Zhang
- College of Plant Science, Jilin University, Changchun, China
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Sun J, Yang R, Liu Y, Zhou Z, Jia J, Huang H, Xiao S, Xue C. An efficient targeted gene deletion approach for Cochliobolus heterostrophus using Agrobacterium tumefaciens-mediated transformation. J Microbiol Methods 2024; 216:106863. [PMID: 38036223 DOI: 10.1016/j.mimet.2023.106863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023]
Abstract
Cochliobolus heterostrophus is a plant pathogenic fungus of southern corn leaf blight, which has been regarded as a model necrotrophic plant pathogen. Many methods have been developed to knock out targeted genes in C. heterostrophus, of which the most widely-used one is protoplast-mediated transformation. However, there are several problems of this method associated with protoplast preparation, DNA product, time consumption, or high cost. In this study, a highly efficient target gene deletion approach in C. heterostrophus was established and optimized, based on Agrobacterium tumefaciens-mediated transformation (ATMT); the transformation efficiency of this approach was 85-88 transformants per 105 conidia, and the homologous recombination efficiency was approximately 68.3%. Furthermore, six gene knockout mutants of C. heterostrophus were obtained using this ATMT method. The phenotypes of this fungus altered in the mutant strains, and the virulence of the mutants significantly reduced compared to of the wild type strain. Taken together, this ATMT system established in this study can be used as a genetic manipulation tool for C. heterostrophus, to better understand the functions of genes and its relation to virulence.
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Affiliation(s)
- Jiaying Sun
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China
| | - Rui Yang
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China
| | - Yujia Liu
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China
| | - Zengran Zhou
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China
| | - Jiaqi Jia
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China
| | - Hongming Huang
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China
| | - Shuqin Xiao
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China.
| | - Chunsheng Xue
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, PR China.
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Jia W, Yu H, Fan J, Zhang J, Su L, Li D, Pan H, Zhang X. Crucial Roles of the High-Osmolarity Glycerol Pathway in the Antifungal Activity of Isothiocyanates against Cochliobolus heterostrophus. J Agric Food Chem 2023; 71:15466-15475. [PMID: 37877171 DOI: 10.1021/acs.jafc.3c04853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Isothiocyanates (ITCs) that are found in Brassicaceae exhibited obvious antifungal activity against Cochliobolus heterostrophus, which is the causal agent of southern corn leaf blight. However, the underlying antifungal mechanism of allyl-ITCs (A-ITCs) against C. heterostrophus remains largely unknown. Here, we used transcriptomic analysis to find that the high osmolarity pathway was upregulated significantly when treated with A-ITCs. To investigate the roles of the high osmolarity pathway in adaption to A-ITCs, we constructed Δssk2, Δpbs2, and Δhog1 mutant strains. Deletion of three genes (ChSSK2, ChPBS2, and ChHOG1) involved in the high osmolarity pathway resulted in significantly increased sensitivity of C. heterostrophus to ITCs. In addition, the phosphorylation level of ChHog1 was induced by A-ITC and was dependent on the presence of ChSsk2 and ChPbs2. Moreover, Δssk2, Δpbs2, and Δhog1 mutants exhibited a dramatically decreased virulence on maize leaves. Our findings demonstrated that the high osmolarity pathway played a positive role in ITC tolerance and virulence, which may provide novel insights into developing ITCs as a new fungicide against C. heterostrophus.
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Affiliation(s)
- Wantong Jia
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Huilin Yu
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Jinyu Fan
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Jiyue Zhang
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Longhao Su
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Dan Li
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Hongyu Pan
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Xianghui Zhang
- College of Plant Science, Jilin University, Changchun 130062, China
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Yu H, Jia W, Zhao M, Li L, Liu J, Chen J, Pan H, Zhang X. Antifungal mechanism of isothiocyanates against Cochliobolus heterostrophus. Pest Manag Sci 2022; 78:5133-5141. [PMID: 36053944 DOI: 10.1002/ps.7131] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 08/06/2022] [Accepted: 08/20/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Isothiocyanates (ITCs) generated from the 'glucosinolates-myrosinase' defense system in the Brassicaceae exhibit broad antagonistic activity to various fungal pathogens. Nevertheless, the antifungal activity of ITCs to non-adapted fungi of Brassicaceae plants were seldom determined. The inhibitory effects of ITCs on Cochliobolus heterostrophus were evaluated and the antagonistic mechanism was explored. RESULTS The mycelium growth of C. heterostrophus was hindered significantly by allyl, 4-(methylthio)-butyl, and phenyethyl ITCs, 4MTB-ITC exhibited the highest inhibitory effect on mycelium growth with an IC50 value of 53.4 μmol L-1 . In addition, ITCs exhibited obvious inhibitory effect on conidia germination and pathogenicity of C. heterostrophus. Proteomic analysis indicated that the inhibition of C. heterostrophus by A-ITC downregulated the expression of genes related to energy metabolism, oxidoreductase activity, melanin biosynthesis, and cell wall-degrading enzymes. Furthermore, mutants ΔChtrx2 and ΔChnox1 showed increased sensitivity to ITCs, and melanin biosynthesis was inhibited significantly in C. heterostrophus in response to A-ITC. Interestingly, unlike other pathogens that infected Brassicaceae plants, the SaxA in C. heterostrophus displayed no function in ITC degradation. In addition, the ITCs also exhibited obvious inhibitory effect on mycelium growth of Setosphaeria turcica, Fusarium graminearum, and Magnaporthe oryzae. CONCLUSION This study indicated that non-Brassicaceae-adapted pathogens are more sensitive to ITCs, and ITCs could have applications in protecting non-Brassicaceae crops in future. In addition, loss of ChNOX1 and ChTRX2 increased the sensitivity of C. heterostrophus to ITCs. Our results provided potential utilization of ITCs to control diseases caused by non-Brassicaceae pathogenic fungi. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Huilin Yu
- College of Plant Science, Jilin University, Changchun, China
| | - Wantong Jia
- College of Plant Science, Jilin University, Changchun, China
| | - Meixi Zhao
- College of Plant Science, Jilin University, Changchun, China
| | - Le Li
- College of Plant Science, Jilin University, Changchun, China
| | - Jinliang Liu
- College of Plant Science, Jilin University, Changchun, China
| | - Jingyuan Chen
- Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Zhuhai, China
| | - Hongyu Pan
- College of Plant Science, Jilin University, Changchun, China
| | - Xianghui Zhang
- College of Plant Science, Jilin University, Changchun, China
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Tsuji K, Kitade Y, Yoshimi A, Tanaka C. Meiotic Silencing in Dothideomycetous Bipolaris maydis. Front Fungal Biol 2022; 3:931888. [PMID: 37746229 PMCID: PMC10512333 DOI: 10.3389/ffunb.2022.931888] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/24/2022] [Indexed: 09/26/2023]
Abstract
The filamentous ascomycete Bipolaris maydis is a plant pathogen that causes corn leaf blight and has been used in cytological studies of sexual reproduction. In this fungus, when null mutants of each septin are crossed with the wild-type strain, all ascospores derived from the same asci show abnormal morphology. The phenomenon was remarkably similar to the event known as "ascus dominance" in Neurospora crassa, which is known to be caused by MSUD (meiotic silencing by unpaired DNA). However, it is not clear whether B. maydis possesses functional MSUD. The object of this study is to elucidate whether this fungus carries a functional MSUD system that causes ascus dominance in the crosses of septin mutants and the wild-type strain. The results of homozygous and heterozygous crossing tests with mutants, having the insertional CDC10-septin gene sequence into the genome, suggested that the ascus dominance in B. maydis is triggered by the unpaired DNA as in N. crassa. To investigate whether MSUD is caused by the same mechanism as in N. crassa, an RNA-dependent RNA polymerase, one of the essential factors in MSUD, was identified and disrupted (Δrdr1) in B. maydis. When the Δrdr1 strain was crossed with each mutant of the septins, ascus dominance did not occur in all crosses. These results suggest that this ascus dominance is caused by RNA silencing triggered by an unpaired gene, as in N. crassa, and septin genes were affected by this silencing. To date, although MSUD has been found only in Fusarium graminearum and N. crassa, which are classified as Sordariomycetes, this study showed that MSUD is also functional in B. maydis, which is classified as a Dothideomycete. These results showed the possibility that this posttranscriptional regulation is extensively conserved among filamentous ascomycetes.
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Affiliation(s)
- Kenya Tsuji
- Laboratory of Terrestrial Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- Laboratory of Environmental Interface Technology of Filamentous Fungi, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yuki Kitade
- Laboratory of Terrestrial Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Akira Yoshimi
- Laboratory of Terrestrial Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- Laboratory of Environmental Interface Technology of Filamentous Fungi, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Chihiro Tanaka
- Laboratory of Terrestrial Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- Terrestrial Microbiology and Systematics, Global Environmental Studies, Kyoto University, Kyoto, Japan
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Yu H, Jia W, Xiao K, Jiao W, Zhang X, Pan H. The Autophagy Genes ChATG4 and ChATG8 Are Required for Reproductive Development, Virulence, and Septin Assembly in Cochliobolus heterostrophus. Phytopathology 2022; 112:830-841. [PMID: 34664975 DOI: 10.1094/phyto-06-21-0271-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Autophagy is a highly conserved degrading process that is crucial for cell growth and development in eukaryotes, especially when they face starvation and stressful conditions. To evaluate the functions of Atg4 and Atg8 in mycelial growth, asexual and sexual development, and virulence in Cochliobolus heterostrophus, ΔChatg4 and ΔChatg8 mutants were generated by gene replacement. Strains deleted for ChATG4 and ChATG8 genes showed significant changes in vegetative growth and development of conidia and ascospores compared with the wild-type strain. The autophagy process was blocked and virulence was reduced dramatically in ΔChatg4 and ΔChatg8 mutants. In addition, deletion of ChATG4 and ChATG8 disordered Cdc10 subcellular localization and formation of septin rings. The direct physical interaction between ChAtg4 and ChAtg8 was detected by yeast two-hybrid assay, and ChAtg4-GFP was dispersed throughout the cytoplasm, although GFP-ChAtg8 appeared as punctate structures. All phenotypes were restored in complemented strains. Taken together, these findings indicate that ChATG4 and ChATG8 are crucial for autophagy to regulate fungal growth, development, virulence, and localization of septin in C. heterostrophus.
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Affiliation(s)
- Huilin Yu
- College of Plant Science, Jilin University, Changchun 130012, China
| | - Wantong Jia
- College of Plant Science, Jilin University, Changchun 130012, China
| | - Kunqin Xiao
- College of Plant Science, Jilin University, Changchun 130012, China
| | - Wenli Jiao
- College of Plant Science, Jilin University, Changchun 130012, China
| | - Xianghui Zhang
- College of Plant Science, Jilin University, Changchun 130012, China
| | - Hongyu Pan
- College of Plant Science, Jilin University, Changchun 130012, China
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Yoshida H, Tanaka C. An arabinose-induced enhancement of asexual reproduction and concomitant changes in metabolic state in the filamentous fungus Bipolaris maydis. Microbiology (Reading) 2021; 167. [PMID: 33555250 DOI: 10.1099/mic.0.001009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
l-Arabinose, a major constituent pentose of plant cell-wall polysaccharides, has been suggested to be a less preferred carbon source for fungi but to be a potential signalling molecule that can cause distinct genome-wide transcriptional changes in fungal cells. Here, we explore the possibility that this unique pentose influences the morphological characteristics of the phytopathogenic fungus Bipolaris maydis strain HITO7711. When grown on plate media under different sugar conditions, the mycelial dry weight of cultures on l-arabinose was as low as that with no sugar, suggesting that l-arabinose does not substantially contribute to vegetative growth. However, the intensity of conidiation on l-arabinose was comparable to or even higher than that on d-glucose and on d-xylose, in contrast to the poor conidiation under the no-sugar condition. To explore the physiological basis of the passive growth and active conidiation on l-arabinose, we next investigated cellular responses of the fungus to these sugar conditions. Transcriptional analysis of genes related to carbohydrate metabolism showed that l-arabinose stimulates carbohydrate utilization through the hexose monophosphate shunt (HMP shunt), a catabolic pathway parallel to glycolysis and which participates in the generation of the reducing agent NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate). Then, the HMP shunt was impaired by disrupting the related gene BmZwf1, which encodes glucose-6-phosphate dehydrogenase in this fungus. The resulting mutants on l-arabinose showed remarkably decreased conidiation, but a conversely increased mycelial dry weight compared with the wild-type. Our study demonstrates that l-arabinose acts to enhance resource allocation to asexual reproduction in B. maydis HITO7711 at the cost of vegetative growth, and suggests that this is mediated by the concomitant stimulation of the HMP shunt.
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Affiliation(s)
- Hiroshi Yoshida
- Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Chihiro Tanaka
- Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Simaan H, Shalaby S, Hatoel M, Karinski O, Goldshmidt-Tran O, Horwitz BA. The AP-1-like transcription factor ChAP1 balances tolerance and cell death in the response of the maize pathogen Cochliobolus heterostrophus to a plant phenolic. Curr Genet 2019; 66:187-203. [PMID: 31312934 DOI: 10.1007/s00294-019-01012-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 06/23/2019] [Accepted: 07/01/2019] [Indexed: 01/01/2023]
Abstract
Fungal pathogens need to contend with stresses including oxidants and antimicrobial chemicals resulting from host defenses. ChAP1 of Cochliobolus heterostrophus, agent of Southern corn leaf blight, encodes an ortholog of yeast YAP1. ChAP1 is retained in the nucleus in response to plant-derived phenolic acids, in addition to its well-studied activation by oxidants. Here, we used transcriptome profiling to ask which genes are regulated in response to ChAP1 activation by ferulic acid (FA), a phenolic abundant in the maize host. Nuclearization of ChAP1 in response to phenolics is not followed by strong expression of genes needed for oxidative stress tolerance. We, therefore, compared the transcriptomes of the wild-type pathogen and a ChAP1 deletion mutant, to study the function of ChAP1 in response to FA. We hypothesized that if ChAP1 is retained in the nucleus under plant-related stress conditions yet in the absence of obvious oxidant stress, it should have additional regulatory functions. The transcriptional signature in response to FA in the wild type compared to the mutant sheds light on the signaling mechanisms and response pathways by which ChAP1 can mediate tolerance to ferulic acid, distinct from its previously known role in the antioxidant response. The ChAP1-dependent FA regulon consists mainly of two large clusters. The enrichment of transport and metabolism-related genes in cluster 1 indicates that C. heterostrophus degrades FA and removes it from the cell. When this fails at increasing stress levels, FA provides a signal for cell death, indicated by the enrichment of cell death-related genes in cluster 2. By quantitation of survival and by TUNEL assays, we show that ChAP1 promotes survival and mitigates cell death. Growth rate data show a time window in which the mutant colony expands faster than the wild type. The results delineate a transcriptional regulatory pattern in which ChAP1 helps balance a survival response for tolerance to FA, against a pathway promoting cell death in the pathogen. A general model for the transition from a phase where the return to homeostasis dominates to a phase leading to the onset of cell death provides a context for understanding these findings.
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Affiliation(s)
- Hiba Simaan
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Samer Shalaby
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel.,Rockefeller University, New York, NY, 10065, USA
| | - Maor Hatoel
- Technion Genome Center, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Olga Karinski
- Technion Genome Center, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Orit Goldshmidt-Tran
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Benjamin A Horwitz
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel.
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Sermons SM, Balint-Kurti PJ. Large Scale Field Inoculation and Scoring of Maize Southern LeafBlight and Other Maize Foliar Fungal Diseases. Bio Protoc 2018; 8:e2745. [PMID: 34179272 DOI: 10.21769/bioprotoc.2745] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/10/2018] [Accepted: 02/14/2018] [Indexed: 11/02/2022] Open
Abstract
Field-grown maize is inoculated with Cochliobolus heterostrophus, causal agent of southern leaf blight disease, by dropping sorghum grains infested with the fungus into the whorl of each maize plant at an early stage of growth. The initial lesions produce secondary inoculum that is dispersed by wind and rain, causing multiple cycles of infection that assures a high uniform disease pressure over the entire field by the time of disease scoring, which occurs after anthesis. This method, with slight modifications, can also be used to study the maize fungal diseases northern leaf blight (caused by Exserohilum turcicum) and gray leaf spot (Cercospora zeae-maydis).
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Affiliation(s)
- Shannon M Sermons
- Plant Science Research Unit USDA-ARS, Raleigh NC, USA and Dept. of Entomology and Plant Pathology, NC State University, Raleigh NC, USA
| | - Peter J Balint-Kurti
- Plant Science Research Unit USDA-ARS, Raleigh NC, USA and Dept. of Entomology and Plant Pathology, NC State University, Raleigh NC, USA
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Lai YR, Lin PY, Chen CY, Huang CJ. Feasible Management of Southern Corn Leaf Blight via Induction of Systemic Resistance by Bacillus cereus C1L in Combination with Reduced Use of Dithiocarbamate Fungicides. Plant Pathol J 2016; 32:481-488. [PMID: 27721698 PMCID: PMC5051567 DOI: 10.5423/ppj.oa.02.2016.0044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/19/2016] [Accepted: 07/11/2016] [Indexed: 06/06/2023]
Abstract
Dithiocarbamate fungicides such as maneb and mancozeb are widely used nonsystemic protectant fungicides to control various plant fungal diseases. Dithiocarbamate fungicides should be frequently applied to achieve optimal efficacy of disease control and avoid either decline in effectiveness or wash-off from leaf surface. Dithiocarbamates are of low resistance risk but have the potential to cause human neurological diseases. The objective of this study was to develop a strategy to effectively control plant disease with reduced use of dithiocarbamtes. Southern corn leaf blight was the model pathosystem for the investigation. When corn plants were drench-treated with Bacillus cereus C1L, a rhizobacterium able to induce systemic resistance in corn plants against southern leaf blight, frequency of spraying dithiocarbamate fungicides could be decreased. The treatment of B. cereus C1L was able to protect maize from southern leaf blight while residues of dithiocarbamates on leaf surface were too low to provide sufficient protection. On the other hand, frequent sprays of mancozeb slightly but significantly reduced growth of corn plants under natural conditions. In contrast, application of B. cereus C1L can significantly promote growth of corn plants whether sprayed with mancozeb or not. Our results provide the information that plant disease can be well controlled by rhizobacteria-mediated induced systemic resistance in combination with reduced but appropriate application of dithiocarbamate fungicides just before a heavy infection period. An appropriate use of rhizobacteria can enhance plant growth and help plants overcome negative effects caused by dithiocarbamates.
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Affiliation(s)
- Yi-Ru Lai
- Department of Plant Medicine, National Chiayi University, Chiayi 60004, Taiwan,
Republic of China
| | - Pei-Yu Lin
- Department of Plant Medicine, National Chiayi University, Chiayi 60004, Taiwan,
Republic of China
| | - Chao-Ying Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 10617, Taiwan,
Republic of China
| | - Chien-Jui Huang
- Department of Plant Medicine, National Chiayi University, Chiayi 60004, Taiwan,
Republic of China
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